If you compare games of past masters with modern master games you will find that the modern masters are playing at a significantly higher level. This is because modern chess masters are able to draw inspiration from and refine the ideas of the older masters. If they weren't doing this, chess theory would become stagnant and new ideas would be few and far inbetween.
Chess is a very difficult game, and nobody will fault you for trying to improve by reading general chess theory. In fact, most people (myself included) would commend you for studying chess to become a stronger player. If you want to become great at chess you have to become a great student of the craft, as with any artform. Indeed, you will struggle to find a single great artist in the history of mankind who didn't study the work of people that came before them. It's simply a very important aspect of how human beings learn things, and it is what drives society forward.
Don't romanticize/fetischize the idea of reinventing the wheel, it's a fool's errand. If you want to improve, it is not wrong to ask for guidance from people who are better than you (with the caveat that not every good chess player is also a good chess teacher). With knowledge comes confidence, and with confidence comes independence and creativity. This doesn't really depend on whether you discovered the knowledge or if someone gave it to you.
As a final note, positional concepts like central control and piece activity and coordination are far more difficult to come up with than they are to understand (at least superficially) once explained. Just because a concept is easy to understand doesn't mean that it's easy to come up with, so don't feel bad for not coming up with these things on your own. Believe me, while most players know about these concepts only very few players have actually managed to master these concepts completely. And with regards to specific openings: you have absolutely no chance of coming up with these concrete openings on your own! The modern theory of Queen's gambit/Sicilian is the result of centuries of intensive development by the greatest players of their time trying to outfox their competitors by coming up with one creative new idea at the time. Some of these ideas became part of established theory and others fell into obscurity, but every single one of these innovations required a great deal of effort. There is no way a single human being could ever dream of coming up with all these ideas on their own.


Chess engine algorithms are implementation dependent, thus there is no such thing as "standard numerical values". Unfortunately, you will need to come up with your own values. However, you can apply some common sense such as the piece value for a queen must be higher than a rook. If you're confused, please take a look at the TSCP source code. It's a very simple chess engine.

Everything you mention is standard in chess. When you play chess, you do look the attacking/defending pieces, right?

Please take a read on:

https://chessprogramming.wikispaces.com/Evaluation

Modern chess engines such as Stockfish has many more evaluation terms. The difficulty in coding a evaluation function is the main motivation for machine learning (neural networks).


Best reply to C46 Four knights, Italian variation

5.Bxf7+ has a reasonable idea behind it, in that it exposes Black's king and jettisons White's bishop before Black can use the fork trick on it that would follow with 5.Nxe4 d5. However, it has some concrete problems:

After 5...Kxf7 6.Nxe4, Black plays 6...d5 and forms a massive center.
Black's king turns out to not be vulnerable on f7. It will quickly retreat to g8 where it is relatively safe.
White's knights are going to get kicked around a lot with loss of tempo. If he plays 7.Neg5+ Kg8, both ...h6 and ...e4 will attack knights that don't have very good places to flee to.

In contrast, after 5.Nxe4 d5, Black regains his sacrificed piece, but has to break up his pawn center in the process. After 6.Bd3 dxe4 7.Bxe4, White no longer has his opening advantage but the position is relatively equal.

The lesson from all of this is that 4.Bc4 is not a very good move. The standard alternatives are 4.Bb5 (Spanish Four Knights), 4.d4 (Scotch Four Knights), and 4.g3 (Glek Four Knights), which all keep White's opening advantage.

P.S. I should point out that there is a third alternative for White's fifth move, 5.0-0, gambiting a pawn for a lead in development. This is likely actually better than either 5.Bxf7+ or 5.Nxe4, but if you want to play a gambit like that then there are much better ones to play than the Italian Four Knights.


Need I be concerned about being classed as a "cheater" if I sometimes play good classical games on LiChess?

Lichess is definitely very good at avoiding false positivies and rectifying those false positives when they do occur.

Even though I don't have access to moderator tools on lichess, one can spot cheaters fairly easily. They usually have the following characteristics:

A "flat" time graph where all of their moves took about the same length of time - even simple recaptures.
Having no mistakes, and less than three inaccuracies (obviously)
Perfectly executing a long checkmate sequence in the fastest way possible. This is a good catch because even a good player will likely turn a mate in 6 into a mate in 7 or 8. Computers do it perfectly.

Numbers 1 and 2 are fine by themselves IMO, so you have nothing to worry about unless you spend the same amount of time on each move in those games where you have few inaccuracies. Number 3 is a sort of "icing on the cake" for me; your games look fine.


Play Chess Variants

Capablanca suggested to add to new pieces, a Bishop-Knight compound and a Rook-Knight-compound, to the setup and enlarge the board size to 10 files and 8 rows. Computer experiments suggest that Capablanca Chess and some variations of it (putting the new pieces on different files than Capablanca) are less drawish than Classical Chess, see this comment on Schoolbook on chessvariants.org)

If you want a balanced and very decisive Chess Variant, try Shogi.


If a pawn is promoted to queen beside the king is the king instantly in check?

Per FIDE Chess Laws, rule 3.1, a piece is said to attack an opponent’s piece if the player’s piece can make a capture on that square (and in one more special case not relevant here).  In full:

It is not permitted to move a piece to a square occupied by a piece of the same colour. If a piece moves to a square occupied by an opponent’s piece the latter is captured and removed from the chessboard as part of the same move. A piece is said to attack an opponent’s piece if the piece could make a capture on that square according to Articles 3.2 to 3.8.
A piece is considered to attack a square even if this piece is constrained from moving to that square because it would then leave or place the king of its own colour under attack.

Per rule 3.9, the king is in check when it is attacked by one or more of the opponent’s pieces.
Therefore, as soon as the move is completed, the king is in check.


Is it possible to checkmate with rook and knight against just king?

Yes, since K+R is an easy beginner checkmate.  In fact, the Knight will get in the way.  The only value of the Knight will be to get White into Zugzwang quicker (easier?), which helps Black push the king to an edge.

To answer the specific question, from above, assuming Black to move:

1... Kc3
2. Ka1 Rc1#

Assuming White to move:

1. Ka1 Kc3
2. Kb1 Kb3
3. Ka1 Rc1#


What is the shortest possible legal game where there are 6 pawns on the a-file or h-file?

This has already been asked and proven on Puzzling Stack Exchange. Courtesy of @xnor, who gave a game and the proof, the shortest possible game is in 31 moves,
[FEN ""]

1. Nf3 Nf6 2. Nd4 Nd5 3. Nc6 dxc6 4. g4 Bf5 5. gxf5 h5 6. f4 Nd7 7. e4 Ne5 8. fxe5 Qd6 9. exd6 exd6 10. exd5 g6 11. Na3 Bg7 12. Rb1 Bd4 13. h4 Bc5 14. d4 g5 15. hxg5 Rh6 16. dxc5 dxc5 17. Bd2 Re6+ 18. fxe6 fxe6 19. Ba6 exd5 20. c4 dxc4 21. Ba5 Ke7 22. b4 cxb4 23. g6 bxa3 24. Rb6 bxa6 25. Rxh5 cxb6 26. Rb5 bxa5 27. Qb3 cxb3 28. g7 bxa2 29. g8=Q cxb5 30. Qg4 Ke8 31. Qa4 bxa4

For fun, here is a retrograde analysis chess problem. It shows the same effect, but the six pawns piling on the e-file do so in a unique move sequence!
[Title "Nicolas Dupont, Problemesis 06/2002, Proof Game In 20.5 Moves"]
[FEN ""]

1. h4 g5 2. hxg5 Nf6 3. gxf6 Bh6 4. fxe7 Be3 5. dxe3 b5 6. Qd6 b4 7. Qg3 b3 8. axb3 c5 9. Ra4 c4 10. bxc4 d5 11. cxd5 Be6 12. dxe6 Qd5 13. Rah4 Qf3 14. gxf3 Rg8 15. Bg2 Rg4 16. Kf1 Re4 17. fxe4 a5 18. f4 a4 19. Nf3 Ra5 20. Rg1 Re5 21. fxe5

Source: The Die Schwalbe Chess Problem Database


Chess opening and chess master to look up to

This is kind of a weird question because, as you rightly note, open games usually are more tactical and sharper than closed games. But it is possible to play 1.e4, and by extension the open games, in a quieter and more positional manner than is usually done.

The most famous proponent of this way of playing is Anatoly Karpov, who played 1.e4 throughout his life and is nevertheless regarded as a very positional player.

But the player I would recommend you study is a different one:
I have always found that, of all world class players nowadays, Mickey Adams is the most instructive to follow. Like Karpov he is a 1.e4 player and something of a positional genius. Unlike Karpov he doesn't rely on a team of seconds to get him to the forefront of theory, so I have always found him to play more "ordinary" positions. If you look at his games you can usually easily imagine getting this kind of position in your own games (unlike some super sharp 30-move theory battle other players indulge in).

Generally regarding openings this would mean playing the Ruy Lopez against 1…e5, the Tarrasch against 1…e6 and either the Rossolimo or some short castles + a4 + f4 against the sicilian.
Against 1.e4 you would play e5. And against 1.d4 I think Adams usually plays the Nimzo, though that might be outside the scope of this question aka open positions.


Can this exchange-down endgame be explained succinctly?

This endgame is completely winning for black with best play.  While there are some cases where the weaker side can build a fortress, those only occur with 1 or 2 pawns per side, not with 3 undoubled pawns.

For example, here is the most common fortress (with 2 pawns each):

[FEN "6k1/1R6/4K1p1/7p/8/2b3P1/7P/8 w - - 0 1"]

White cannot break down black's defense.  If the white king tries to come to g5, black prevents this with ...Bf6! when the white king appears on f4.

Dvoretsky's endgame manual explains succinctly:

  With three pawns on each side a fortress, as a rule, cannot be build.  Salvation is possible only in exceptional cases: when the pawn structure of the stronger side has flaws.

As an extreme case, look at the most "advantageous case for the weaker side, with the pawns in contact (the variation is from an actual game while the main line is black's best try):

[FEN "6k1/3R4/6p1/5p1p/5P1P/3K2P1/1b6/8 w - - 0 1"]

1. Kc4 Kf8 2. Kd5 Kg8 3. Ke6 Bc3 4. Rd3 $1 Bb2 5. g4 $3 $18 fxg4 (5... hxg4 6. h5 Kg7 7. hxg6 Kxg6 8. Rd5 Bc1 9. Rxf5 Bxf4 10. Rxf4 Kg5 11. Ke5 g3 12. Ke4 g2 13. Rf8 Kh4 14. Rg8) 6. f5 gxf5 7. Kxf5 Kf7 8. Kg5 Be5 9. Kxh5 g3 10. Rd2 Kf6 11. Kg4 Kg6 12. Re2 Bb8 13. h5+ Kh6 14. Re6+ Kh7 15. Rg6 Bc7 16. Kf5 Bb8 17. Rb6 $1

Now that we've established that the stronger side can win, even with the pawns in contact, let's look at the case in the question:

Black's winning plan is quite simple, bring the king to e1 to attack the pawn on f2 with both the rook and the king (forcing its advance to f4), and then black will bring the king back to e3, bring all 3 pawns to the 3rd rank, and finally push g6-g5, forcing weaknesses.

Here is a sample line.  It is just a single example, there are many other options for both colors, but hopefully it illustrates the winning plan for the stronger side.

[FEN "6k1/5ppp/8/8/1r6/5KP1/5P1P/5B2 b - - 0 1"]
[PlyCount "41"]

1... Kf8 2. Ke3 Ke7 3. Bd3 g6 4. Kf3 Kd6 5. Ke3 Ke5 6. Kf3 Kd4 7. Be2 Rb3+ 8.
Kg2 Kc3 9. Bf3 Kd2 10. Bc6 (10. Bd5 Rb2 11. Bxf7 Ke1 12. Bg8 Rxf2+ 13. Kg1 h6
14. Bd5 Ke2 15. Be6 Rf6 16. Bc4+ Ke3 17. Bb5 h5 18. Kg2 Rf2+ 19. Kg1 Rc2 20.
Ba4 Rc4 21. Bb3 Rd4 22. h4 Rd2 23. Bf7 Kf3 24. Bxg6 Kg4 25. Kf1 Rd6 26. Be8 Rd8
27. Bb5 Kxg3 28. Ke2 Kxh4) 10... Ke1 11. f4 Rb2+ 12. Kg1 Ke2 13. Kg2 Ke3+ 14.
Kg1 f6 15. h4 h6 16. Bd5 (16. Ba8 g5 17. fxg5 hxg5 18. hxg5 Rb8 19. Bc6 Rb6 20.
Ba8 f5 21. g4 f4) 16... g5 17. fxg5 hxg5 18. Bc6 (18. hxg5 Rb5) 18... gxh4 19.
gxh4 f5 20. h5 Rb6 21. Be8 f4 0-1

To finish this answer, consider the position if white has instead a dark squared bishop.  In this case, black's plan is very similar - attack the f2 pawn.  Black brings the king to e2, the rook to f3, and then advances the pawns (g7-g5, f7-f5-f4 - potentially including h7-h6 if needed) to break through.

Hopefully this gives you all of the plans needed to win as the stronger side.  The defensive chances with fewer than 3 pawns each are also worth examination, but they're probably worth a question on their own.


Why is it a good idea to fianchetto above the castled King? If I do that, should I make sure to leave the Bishop there for a while to guard the hole?

Fianchettoes are a very common and strong setup. But watch also for the 2 most common attacks against a fianchettoed position, which are:

A. Launching the rook pawn up the board (against Black this would be h4-h5 etc.) and opening up the h-file. I have played this many times against the Pirc where Black "castles into" the attack. White plays h4-h5 followed by trading off the pawn and then plays Qh6+ with a very strong attack down the open file.

B. The sacrifice of a knight on f5 (where Black accepting the sac would play ...gxf5). This wrenches open the position and jacks up the pawn structure.

Even if the opponent trades his same-color bishop for your fianchettoed bishop, you can still become weak on that color complex (e.g. the opponent's queen can roost on h6 for example and be a thorn in your side)


Can white king capture defended pawn by pinned piece?

No.

The king must not move to a square under attack by an enemy piece, no matter what, even if said attack is currently not allowed.

If the rule allowed exceptions like this, the logic would chase its own tail: If White is allowed to play Kxf4 - placing his king in danger of getting captured with the excuse that Black (supposedly) can't actually take it next move -, then by the same logic, Black should be allowed to play Bxf4, too - placing his king in danger of getting captured with the excuse that White cannot actually take it next move (because there is no next move as soon as White's king is captured)! But if Black is allowed to play Bxf4, then Kxf4 gets illegal again, because now the danger of recapture is real.

Thus, to avoid these headaches, White is not allowed to play Kxf4 in the first place.


Using Stockfish in an automated way, for example, to analyze games in pgn format

There is a library for Python (import chess.engine) that allows you to use an engine (like Stockfish) to analyse games in a PGN file.


The only opening move I really didn't like is 6…Nc6. Usually you don't want to put something in front of your c-pawn in these d-pawn openings. And incidentally it also seems to lose a piece (because of 8.cxd5 with Bb5 to follow). It also leads to all your positional problems: The pressure on d5, the slightly weakening move f6, the inability to free yourself with c5.

Your thought process is ok, Be7 and castling short is a decent conclusion. But you probably should have looked for a tactical solution as well: 12…dxc4 looks quite interesting for you. 13.Bxc4 is not possible, due to 13…b5 and Qxc4 can be answered by Na5 and Bxg2. Ok, it's not exactly risk free, but it's a pawn. Also, the bishop on b7 is really waiting for the diagonal to be opened sooner or later, so it should always be on your radar.

Generally to improve your strategic understanding you can do the usual stuff: Go through well annotated games, play and analyse tournament games, work through some instructive books. But on the other hand, putting your pieces on nice squares and waiting for something to come up, is an entirely valid strategy. Also, finding some creative tactical ideas can often substitute for a deep strategic plan and without decent calculation you can forget about implementing even the best plan.


What should I do when my opponent and I are "chasing" each other around?

What should I do in such a situation?

Shake hands and agree a draw.

If it is a serious game where you are writing down the moves and your opponent doesn't agree to a draw then mark the move on your scoresheet where the last time a pawn was moved or a capture was made, mark the move 50 moves on from that and when you reach that move make a draw claim under the "50 move rule".


Is the number of legal chess positions odd or even?

Odd if you count the initial position and Even if not.

Mirrored positions

Almost any position, including checkmates and stalemates can be flipped by switching colors.

Mirroring the chess board horizontally between 4 and 5 rows, you cannot find a position that colors can be switched and produce an illegal position. So for each position there exists a mirrored position, except the start position.

The challenge would be to find a position that cannot be mirrored.

Non Mirrored positions / Corresponding positions

There can exist positions where it cannot be mirrored due to the "turn that cannot be switched". For its this position, there would be a "corresponding position" that also cannot be mirrored.

e.g. 1. Nf3 Nf6 2. Ng1 Nd5 3. Nf3 Nf4 4. Ng1 Nd3+

its corresponding condition is:

Nf3 Nf6 2. Nd4 Ng8 3. Nf5 Nf6 4. Nd6+

Both cannot be mirrored.

Triangulation

Due to Triangulation, all positions after a pawn is pushed can be mirrored. Non mirrored positions can be constructed only with knight moves, moving only knights cannot produce Triangulation.

Start position

The start position, before any moves, the turn cannot be switched so that black makes the first move.

Calculating positions from knight moves

To solve this for sure, we need to calculate the total positions that arise from only knight moves.


I have done some Deep Reinforcement Learning so I can tell you that making a NN is not the way forward here and it is far from easy. If you manage to take the NN of LC0 as it is and train it with another algorithm (according to how you want it), you can get your training software. Even designing this algorithm would be difficult.

The point here is that LC0 NN is capable of having a strength matching 3900 levels. It learns patterns in chess very efficiently. If you want a strength of 1600 or 2000 or whatever your rating is, it's definitely more than capable. Maybe you would need a new NN if you want a strength of 4500. Intelligence is already out there. You just have to customize it for your needs.

A much more practical thing would be to try to beat LC0 snapshots of past close to your rating. They should be available on lc0 site, you'll have to make the appropriate frontend. But you can get an easier version by trying to beat stockfish levels on lichess. Maybe you can request the lichess community to add more levels at smaller intervals or make some more yourself.

Earlier engines like Fritz and I guess the very old Deep Blue itself were trained on GM games so this is not anything new. Self play is much stronger and you'll be able to feel playing many levels how NN itself learns patterns step by step.

P.S. Such a thing would help Carlsen, Anand and others much more as you can learn through books but they can't. They can try to beat 2900 LC0 but you can learn from books. Everytime they crush the opponents who write the books we read.


Wedge pawn formation with slight differences

While it's true that your 10. ... Qg5 prevents the freeing break 11. f3?? (due to 11. ... Qxe3+ followed by ... Qxc3), White could get away with 11. f4 in response if so inclined. If you respond by moving the queen, then white is no longer so cramped on the kingside and doesn't have to worry too much about an onslaught on that wing. If you respond with 11. ... exf3 12. Nxf3, your bishop has improved scope, but White has in effect achieved the freeing f3 break your tenth move was meant to prevent.

Maybe more problematic than 11. f4, though, is that White can play 11. Ba3! in reply.

[FEN "rn2k2r/pbpp2pp/1p2p3/6q1/2PPp3/2P1P3/P2N1PPP/R1BQ1RK1 w - - 0 11"]

1. Ba3!

This temporarily prevents castling, and things like 11. ... d6 12. c5 are in the air, when White can have further ideas of play on the b-file (and against your bishop on b7) with Rb1 and/or Qb3. It's not as though Black is in big trouble here, but I think there's no reason to speed up this queenside play with your 10. ... Qg5, especially since your move doesn't prevent a freeing f-pawn move after all. Better to wait a bit, perhaps, for a more opportune time to bring the queen into play.

I think you're absolutely right that Black should aim toward an attack on the kingside, but for the reasons just stated I think you should start off with the straightforward 10. ... O-O instead. It seems that White should still aim for the same kind of queenside play described above, but now you won't have any awkwardness involving castling (or needing ... d6 to achieve it and helping White to start opening up the queenside with c5). Now you'll try to get something going on the kingside while White does the same on the queenside, and unlike above it seems like the two armies are on a pretty even footing. After, say, 11. Ba3 Rf5 12. c5 Qh4,

[FEN "rn1qk2r/pbpp2pp/1p2p3/8/2PPp3/2P1P3/P2N1PPP/R1BQ1RK1 b - - 0 10"]

1... O-O
2. Ba3 Rf5
3. c5 Qh4

each side is doing its thing, and I do think that Black should have a comfortable endgame -- though I don't know that I'd use your word "favorable" for it -- if White should arrange for a queen trade to relieve pressure on the kingside.


Longest period with each piece "hanging"

Since a game with all 14 pieces, as kings are excluded, hanging has probably not happened yet, and will not for a long time, I will answer as best as I can. Under these circumstances, I think that the best that can be done is to locate the highest number possible.
The highest that I have found so far is
6 hanging pieces. I found the full score on chessgames.com. In the board position on move 23, Black can capture three White pieces, and likewise White can also capture three Black pieces.
[Title "Loal W Davis-Magesh Chandran Panchanathan, HB Global Chess Challenge, Minneapolis Minnesota USA, 5/19/2005"]
[FEN ""]
[startply "45"]

1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 d5 5. exd5 Na5 6. Bb5+ c6 7. dxc6 bxc6 8. Be2 h6 9. Nf3 e4 10. Ne5 Bd6 11. f4 exf3 12. Nxf3 O-O 13. d4 Rb8 14. a3 Re8 15. O-O c5 16. Nc3 cxd4 17. Qxd4 Nc6 18. Qh4 Bf5 19. Bd3 Bc5+ 20. Kh1 Bxd3 21. cxd3 Qxd3 22. Bxh6 Rxb2 23. Na4 Rc2 24. Nxc5 Rxc5 25. Bg5 Ne4 26. Bf4 Rc2 27. Ng5 Nxg5 28. Qxg5 Nd4 29. Rfe1 Rce2 30. Rxe2 Qxe2 31. h3 Nc2 32. Rc1 Qe4 33. Bg3 Ne3 34. Bf2 f6 35. Qxe3 Qxe3 36. Bxe3 Rxe3 37. Ra1 a5 38. Ra2 a4 39. Kg1 Kf7 40. Kf2 Rc3 41. Rb2 Rxa3 42. Rb7+ Kg6 43. Ra7 Ra1 44. Kg3 a3 45. Kf2 Kh6 46. Ra5 g6 47. Kg3 Ra2 48. Kf3 f5 49. Ra7 Ra1 50. Kf2 f4 51. Ra8 a2 52. Ra5 f3 53. Kg3 Kg7 54. Ra6 Kf7 55. Kf2 Ke7 56. Kg3 Kd7 57. Kf2 Kc7 58. Ra3 Kb6 59. Ra8 Kc5 60. Rc8+ Kb6

However, if you wish for "pure" position with all pieces hanging, I discovered a beauty on chessgames.com. It holds yet another 6 hanging pieces in the final position after the climactic 33. Be4!
[Title "Veselin Topalov-Alexander Morozevich, NAO Masters, Cannes France, 2/22/2002"]
[FEN ""]
[startply "64"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O b5 6. Bb3 Bc5 7. a4 Rb8 8. c3 d6 9. d4 Bb6 10. axb5 axb5 11. Na3 O-O 12. Nxb5 Bg4 13. Bc2 h6 14. dxe5 Nxe5 15. Nbd4 d5 16. exd5 Qxd5 17. h3 Bh5 18. g4 Nfxg4 19. Nxe5 Nxe5 20. Qxh5 Bxd4 21. Qf5 Nf3+ 22. Kh1 Qxf5 23. Bxf5 Bf6 24. Ra7 c5 25. Be4 Ne5 26. Rd1 Nc4 27. Bb7 Bg5 28. Bxg5 hxg5 29. b3 Ne5 30. Rd5 Rfe8 31. Rxc5 Re7 32. Rb5 Nd3 33. Be4

Lastly, just for giggles, the fastest way reach to such a position is a mere 6 moves.
[title "me, chess.stackexchange.com 10/16/2020 Non-Unique Proof Game In 6.0"]
[FEN ""]

1. e3 e6 2. Qh5 Qh4 3. Qxh7 Qxh2 4. Ba6 Ba3 5. Bxb7 Bxb2 6. Nc3 Nc6

On a semi-related note, the record for the longest time a piece was “hanging” is 24 moves, during which the Black knight on g4 could have been captured by White's h-pawn. Tim Krabbe has it in his "Chess Records" of course, although the score comes from chessgames.con
[Title "Anthony Miles-Ljubomir Ljubojevic, Interpolis 10th, Tilburg Netherlands, 1986"]
[FEN ""]

1. Nf3 c5 2. c4 g6 3. e4 Bg7 4. d4 Nc6 5. dxc5 Qa5+ 6. Nfd2 Qxc5 7. Be2 d6 8. O-O Nd4 9. Bd3 Nf6 10. Nb3 Nxb3 11. axb3 Ng4 12. h3 h5 13. Qd2 Qe5 14. f4 Qc5+ 15. Kh1 Bd7 16. Nc3 e6 17. Qe2 Bd4 18. Bd2 Qb6 19. Nd1 a6 20. Ba5 Qa7 21. Bb4 Qb6 22. Ba5 Qc6 23. Qe1 e5 24. Bb4 Qb6 25. Ba5 Qa7 26. f5 gxf5 27. exf5 Bc6 28. Be4 Kd7 29. f6 Rag8 30. Bxc6+ bxc6 31. Qe4 Qb7 32. Bc3 Ba7 33. b4 Kc8 34. c5 dxc5 35. Qf5+ Kb8 36. Bxe5+ Ka8 37. bxc5 Bxc5 38. Bg3 Ba7 39. Qd3 Ne3 40. Rf3 Rd8 41. Bd6 Nxd1 42. Qxd1 Rhg8 43. b4 Rg5 44. Rd3 c5 45. Bg3 Rgd5 46. Rxd5 Qxd5 47. Qa4 cxb4 48. Qxa6 Qb7 49. Qf1 Rd7 50. Bf2 Qc6 51. Bg1 Rb7 52. Qf2 Qd7 53. Qf3 Kb8 54. Qf4+ Ka8 55. Qe4 Kb8 56. Bxa7+ Rxa7 57. Qxb4+ Ka8 58. Qf8+ Kb7 59. Rxa7+ Kxa7 60. Qe7


The point is that 4...Nc6 could be met with 5.Bb5, when the knight is pinned and it's likely White will exchange it off with Bxc6. Without the c6-knight, Black will lose some influence over the key d4- and e5-squares. Playing ...a6 before developing the knight aims to prevent this.

Of course there's a trade-off here, since Black is spending a tempo just to prevent a relatively innocuous exchange.


How many positions does a GM analyze before making a move?

Of course this depends on the position at hand, but generally speaking...

I am not a GM, but 100 positions (not moves) seems highly exaggerated, though this might depend on your definition of "position" and "analyze".

If you really mean unique (and not only slightly different) positions, and if you mean by analyze, the   full process of evaluating the position, I would guess that the number is between 0 and 3 or so.

Only rarely you would want to calculate  forced line and would have to analyze a position in the future anyway. Most decision making is based on well
known plans, that follow from the current position on the board.


Hanging square and deflection tactic leading to a back rank checkmate

I haven't heard of the term "hanging square" before. But you're right that the c8-rook would be deflected (or "attracted") if it were taken away from defending the rook on e8.


I used to try to imagine the whole board and it always seemed my mind would focus more narrowly. Then, one time when I was doing an exhibition in public versus just one opponent, I suddenly saw the chessboard a different way: it was floating in darkness and the board was translucent, so I could move around the board and see it (and the pieces) from different perspectives. I can't say it improved my play a lot, but it was an amazing experience. I hadn't been seeking a better way. It just appeared to me.

I haven't tried to play blindfold very much over the years, but I have studied chess quite a lot and earned the national master title. I guess our imagination is working hard in any of these ways we do chess.


How is this not checkmate? I had loads of time to spare

A necessary condition for checkmate is that the king is in check, which is not the case here.

The position in question is called stalemate: black does not have any legal moves, but is not in check. The game ends at this point, and is evaluated as a draw.


Is there any published research into the Mighty Thor gambit against the French Defense?

I am not aware of any published analysis nor commented games in this line.

Note that Black can almost forcefully transpose into a 'regular' wing gambit with 4...Nc6 5.Nf3 [5.f4, 5.bc5, and 5.Bb2 cb4 all look worse] cb4.

In case he is looking for more original play, 4...d4, 4/5...Qb6, 4/5...Qc7 all look interesting and try to demonstrate that a3 might not be the most useful move for White when Black refrains from taking on b4.


Which legal position has the smallest number of moves in a "forced loop"?

This legal postion should fit the bill for the least amount of units needed and the least amount of moves. There is one king, one bishop, and four pawns for each side-a total 12 pieces. The threefold repetition is forced no matter what moves the players make since they only have one legal move each time. It's basically your idea in a legal and lighter setting.
[FEN "5b1k/4p1p1/4P1P1/8/8/1p1p4/1P1P4/K1B5 w - - 0 1"]


What is this opening trap I keep encountering in the Englund Gambit?

This is just a series of bad moves by black.
The video linked to by koedem says it's a new "trap," and quite frankly, it requires white to resign after dropping the queen to qualify as a trap.  If white continues 8. Nxc7+, when the dust settles, white still has a slight advantage, having traded a queen for a rook, two pawns and a bishop.  (In this continuation, white will exchange the knight for a rook and lose the pawn on e7.)
If white plays 6. Nxc7+ and captures the knight before capturing the rook, white ends up winning a rook and two pawns outright, and remove's black's castling rights.  So black is taking the risk of a crushing loss in the hopes that white will blunder his way into equality instead.


A chess problem question: Why is this the solution?

What would make you play Nc7?

It is the only move with which White can give check mate in two moves.

  This results in checkmate in 2 if, as the computer does, Rxe5 is played, but why wouldn't the computer just play Nxg5, winning the queen and preventing checkmate?

On 1. ...Nxg5 White plays 2.Rd5 which check mates.

  Or d1 and promote to a queen?

On 1. ...d1Q White plays 2.Rd5 which check mates.

SUMMARY:

1.Nc7 has been played to free the rook on e5 to give check mate, by coming to d5.

This is why computer played 1. ...Rxe5, since on every Black's move 2.Rd5 check mates, except for these:

1. ...Ne3 but then White mates with 2.Rxe4.

1. ...Nxe5 where White mates with 2.Rxd6.

1. ...Bxe5 where White mates with 2.Qxd2.

1. ...dxe5 where White mates with 2.Bc5.

1. ...Kxe5 where White mates with 2.Bg7.

Best regards.


There are all kind of endgames, so it is a bit difficult to generalize, but still there are a few things that are relevant in many cases.

Just like in the middle game you can evaluate the position based on for instance:

material (this is often the most important)
piece activity
weaknesses in pawn structure

Unlike in the middle game "king safety" is often irrelevant as with reduced material it is difficult to get mated and in fact the king often plays an active role in defending/attacking pieces.

If material is equal (as in this example), in many cases you can only win by promoting a pawn. The goal is then simply to create a passed pawn and push it to the other side of the board. To do this, you can either capture opposing pawns or make use of a pawn majority (basically, with the support of your own pawns to walk passed the opponent's pawns). So you should focus on how to create a passed pawn (and of course how to prevent your opponent from doing the same).

In order to improve your endgame technique you should also familiarize yourself with the most common endgames, such as:

mating with K+Q vs K, K+R vs K, K+BB vs K
winning or defending K+P vs K
various endgames with pawns on both sides
K+R and pawn(s) vs K+R (and pawn(s)). This is a very common endgame, but also very difficult to play properly. Perhaps too difficult at your current level.

Also you should know typical themes that appear in endgames like:

zugzwang
corresponding squares
triangulation
stalemate

With this in mind, regarding your example, you note that:

material is equal
opposite colored bishops (which tend to be more drawish)
symmetric pawn structure
blocked pawn chains
pawns on squares of the same color as the opponent's bishop (i.e. they can be attacked by either player. If the pawns were on the same color as the players' bishops, the position would be even more drawish as pawns would be even harder to attack and there would be an additional defender for the pawns (the respective bishop).
weak pawns on d3, g2 and g7

In order to win this position either side would need to create a passed pawn. Because of the symmetrical pawn structure it is difficult to achieve this by pawn breaks except for special situations like this. This leaves as the only option to somehow create a passed pawn by capturing enemy pawns.

How to do this? The most likely candidates for capture would be the weak pawns on d3, g2, g7, however these are easily defended by the king and if necessary the other pieces such as the knight on c1. Also note that it is not really possible to activate the kings (i.e. march the black king to somewhere around c3 or the white one to a more active square), because (i) white/black would have lots of time to attack and win the g7/g2 pawn and subsequently all the other pawns in the chain and (ii) the knight+bishop block the entrance on the a-b-c files (white covers the squares c4, b4, a3, b3 and black the squares c3, b3, b2, a2).

So it seems fairly impossible to just capture the weak pawns and also it seems impossible to create another weakness or passed pawn on the kingside through a pawn break. The last thing I'd check is if there is a possibility for a sacrifice (e.g. white could sacrifice a piece for two pawns on d4. However with the pawns being rather far from the promotion square it seems unlikely to succeed.

An agreed draw would be natural in this position, however at your level there is nothing wrong with playing on in order to practice and it is not impossible to make mistakes in this position. A plan for white could be to play g3 followed by f4 which could lead to another weak pawn on e5 (after capture fxe5 fxe5). Still with correct play it should be a draw.


chess variants similar to retrograde gameplay

This is just my opinion, as I doubt the question can be objectively answered, but I don't think this is feasible.

There are a few big problems arising from the idea of going backwards in the game of chess, and not only that the pawns' movement must be inverted, but also concerning the captured pieces. How to decide when a captured piece can "emerge" from the graveyard is, IMO, quite challenging. One can't simply set that every time an opponent's piece moves, you can put a captured piece on the square just left empty, since this would mean that a player has the right to "move" twice: to choose which piece to put on said position and then to move another (not necessarily different) piece. And this same problem applies to pawn promotion, when a player could choose to transform a piece on the last rank to a pawn on the seventh (or second). This doesn't happen in normal chess and I find it a little of an abomination.

Moreover, assuming all the pieces are already on the board, none of them can be captured (including the king, who now can enter into check but cannot be checked by an enemy piece). Plus, there are several strategies that any of the two players can adopt as to win almost immediately, one of them being to put a knight on the last rank, for example on a bishop's square. It would be impossible to a black piece to dislodge it, but if all the pawns are on their starting squares, the knight can go back to his place while the bishop can never trespass the pawn "chain".

This would lead to problems concerning what moves are legal and what are illegal. If, for example, we assume that a player must be capable of completing his objective, that is, any move that impedes the opposing player to complete his task is illegal (like forcing him to put first all the pawns on their squares but leave out the queen), would mean that one can enter a never-ending discussion of when a knight shall leave the last rank (the pawn has to be two squares advanced, or one, but what if the knight has all the other exits blocked and can no longer move, is it illegal to move the pawn thus A wins or the knight is in an illegal position thus B wins...). Or maybe we shall decide that if a player cannot attain his objective, he directly loses.

Well, I have to accept that maybe it is plausible to make such a game, but that would not resemble much the chess rules, and they would be so complicated that I don't think the game could be playable.


Help trying to invent a tactical chess opening

The Be3 would make more sense on b2 since that would not only support c3 and d4, but also make room for opening the centre via e4 later (after Rf1-e1). Placing a bishop on the 3rd rank in the centre with the pawn behind still on the 2nd rank tends to become awkward.


I'll give instructions for Scid 4.6.4. With this setup, I haven't seen any issues where it moves both sides:

Create a database of openings you want to study. Scid will select randomly from all variations of all games, so make sure you want to train on everything in that database. Open the database switcher and make sure your desired openings database is selected.
Database > Maintenance > Maintenance Window (Ctrl + M). You should see your database name at the top. Next to the name of your database, click the image to the right of "Type Icon:" and select either "Openings for White" or "Openings for Black". Note that this option decides your selection in step 4. Let's say you select "Openings for Black"; the only option you can select in step 4 is to play as Black. If you want to play White, you'll need to either reclassify the database in the Maintenance Window or rotate the board (after you've selected to play black) and it will let you play the White pieces. "Openings for either color" allows you to select playing both sides in the Openings Trainer, but from what I've seen it'll just play one side anyway.

If desired, add additional flags for White or Black openings here in the Maintenance Window. I don't think this does anything for the Opening Trainer.
You may need to restart Scid. Play > Training > Openings. Customize your options (such as which side you want to play) and hit Continue. Play a move and Scid should play the other side if you've selected either White or Black. Once it displays "End of variation" in the window that pops up, you can use the arrow keys to move back to move 1 (or select move 1 in the Notation) and it will randomly select another variation. If you're ever stuck on a move, click "Display candidate moves" in the pop-up and below that button it will show your options.


What is the best approach to this situation?

You are a queen and a piece down. Your position is completely hopeless. Your best move here is to resign the game.
It's not clear how well your opponent has played to reach this position but you have clearly played very badly indeed. An opponent who was good enough to reach this position is going to finish you off very quickly regardless of what you do.
As a beginner you need to start by learning about opening principles, tactics and simple endgames. If you use the search function in this forum you will find many questions and answers that can help you with these.


Finding New York City tournaments as a visitor from Moscow

Most tournaments in the U.S. are not FIDE-rated, but there are some. Your best best are the more-common USCF-rated tournaments. You would have to join the USCF as part of that.

They have a list of tournaments here. Just pick the state you want, in this case, New York.


From the specification:

A basic SAN [Standard Algebraic Notation] move is given by listing the moving piece letter (omitted for pawns) followed by the destination square. Capture moves are denoted by the lower case letter "x" immediately prior to the destination square; pawn captures the file letter of the originating square of the capturing pawn immediately prior to the "x" character.

And

In the case of ambiguities (multiple pieces of the same type moving to the same square), the first appropriate disambiguating step of the three following steps is taken:
First, if the moving pieces can be distinguished by their originating files, the originating file letter of the moving piece is inserted immediately after the moving piece letter.
Second (when the first step fails), if the moving pieces can be distinguished by their originating ranks, the originating rank digit of the moving piece is inserted immediately after the moving piece letter.
Third (when both the first and the second steps fail), the two character square coordinate of the originating square of the moving piece is inserted immediately after the moving piece letter.

1: Rbb7
2: Rab7 or Rcb7
3: fxg5
4: hxg5
5: hxg6
6: Nac3
7: Nbc3 or Ndc3
Note that this is simply how the specification is written. En passant captures should not be an edge case, but they are unlikely to be implemented correctly 100% of the time. You'll have to test your replayer to see whether it handles these cases correctly or not.


What are good chess tournaments to play in Europe as a USCF Class A + age 21+?

You can give a try to the monthly "First Saturday" round-robin tournaments in Budapest. (You probably have heard of it, it has been in existence for like 22 years.)
The city is nice, the venue is downtown, the local girls are beautiful, the majority of the players speak/understand English, maybe the only issue can be that your rating qualifies you for group "FM-A", where the opponents are rated between FIDE 1850 and 2100. But 9-11 games are guaranteed.


Question about four digits appearing next to move

I think you are using "Lucas chess" here with Rybka. Even though Lucas chess is a real neat software, I eventually preferred the (-1 / 0 / +1) kind of representation of the evaluation. Each number next to the move is an evaluation or weight associated with the move. As you can clearly see it is considering many different moves (usually called MultiPV in UCI terms) and giving its evaluations.


Only a general answer can be given for this:

Generally the exchange of R+P (sometimes an extra pawn) for a Bishop and Knight favors the player who has the Bishop and Knight afterwards due to the simple fact that the Minor Pieces are much stronger during the middlegame than the Rook. You have two attacking pieces vs. one attacking piece. The side with the Bishop and Knight will have better attacking chances as they will have more open lines (diagonals are much more open than files in the middlegame) and good squares for the Knight. The Rooks will be blocked by the pawns and unable to contribute much to the game.

Of course, it is very position dependent. In various variations of the Sicilian Defense, Black will exchange a Rook for a Knight on c3, sacrificing the exchange. This is extremely important for Black to do as it creates weaknesses and increases the strength of their dark squared Bishop.

In addition to this, there are many attacks that use the Rooks in the middlegame by opening up the h-file. It's very position dependent as to which group of pieces is more important or not.

As a general rule of thumb though, a Bishop + Knight is considered more important and stronger than a Rook + Pawn.


What are the main ideas and goals in the Queen's Indian Defense?

The key ideas for Black in the Queen's Indian Defense is to:

Restrain White in the center
Quick Development

The Queen's Indian Defense can be reached after the moves:

    [FEN ""]
    1. d4 Nf6 2. c4 e6 3. Nf3 b6

In the Queen's Indian Defense, black is going aim his light-squared bishop and knight at e4 in order to restrain the moves e4 and to prevent d4 to d5.

White's most popular move is 4...g3 in which white aims to complete development on the king side and counter black on the long diagonal.

A key position is reached after the following:

    [FEN ""]
    1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O O-O 7. Nc3

In the above position, 7...d5 might seem like a logical move, but it is against the spirit of the opening which say's that Black should be waiting for the most opportune moment to make moves like 7...d5 which occupy the center until the timing is just right. Also, after exchanging pawns on  d5, black finds himself with 2 problems, the bishop on b7 is blocked in and the c pawn is on an open file and becomes vulnerable to attack.  For example, after white plays Bf4 to eye the c pawn, Black would like to move his pawn to c5, but after the following:

    [FEN ""]
    1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O O-O 7. Nc3 d5 8. cxd5 exd5
    9. Bf4 c5 10. dxc5 bxc5

The above leaves Black with a hanging pawn formation. The d and c pawns are extremely vulnerable and if white can quickly generate an attack such as 11. Ne5 generating a third attacker and pinning the pawn.  Black may continue 11...Na6 and now white has 12. Nc4 taking advantage of the pin with the mindset of getting his knight to e3, so Black often plays Qd7, but White just plays Na5

Going back to positon after 7. Nc3, we just illustrated that 7...d5 is not a logical move for black, so instead he plays 7...Ne4 directly occupying the e4 square making it impossible for white to play e4 and he wants to use his f pawn to strengthen his hold over the e4 square and he won't block the diagonal of his bishop.  After the following:

    [FEN ""]
    1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O O-O 7. Nc3 Ne4
    8. Nxe4 Bxe4 9. Ne1 Bxg2 10. Nxg2 d5

Black is now willing to play d5 because there is not bishop on b7 anymore and he can now gain share of the center and the position is about equal, so after 7...Ne4, white often plays 8. Qc2, 8...f5 looks like a natural response, but white plays 9. Ne5 and would black would quickly find himself in trouble after:

    [FEN ""]
    1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O O-O 7. Nc3 Ne4
    8. Qc2 f5 9. Ne5 d6 10. Nxe4 fxe4 11. Bxe4

In the above diagram, black does not have time to capture the knight because of the bishop and queen staring down the diagonal, so instead of 8...f5, black should play 8...Nxc3 9. Qxc3 f5.  White still has in mind one other factor to gain an advantage.  In addition to still play pawn to e4, he also counts on the fact that blacks e6 pawn will become weak if black plays d6 eventually, so for example:

    [FEN ""]
    1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O O-O 7. Nc3 Ne4
    8. Qc2 Nxc3 9. Qxc3 f5 10. b3 Bf6 11. Bb2 d6 12. Rad1 Qe7 13. Ne1 Bxg2 14. Nxg2 Nd7
   15. Qc2.

White is looking for small small initiative based upon the weakness of the e6 pawn, so in the end the fight for e4 is the major theme that holds the entire Queen's Indian together.


Distracted by opponent's habit of spinning captured pieces

Article 11.5 of the FIDE Laws of Chess covers this:

  It is forbidden to distract or annoy the opponent in any manner
  whatsoever. This includes unreasonable claims, unreasonable offers of
  a draw or the introduction of a source of noise into the playing area.

If your opponent distracts you in this way and refuses to stop when you ask him then you should definitely call the arbiter. The arbiter will ask your opponent to stop this behaviour and will keep an eye on your game. If your opponent ignores the arbiter's instructions then the arbiter will penalise him.

Note that when top players do these potentially disturbing things they are careful to do so out of sight of the opponent so it does not actually disturb them. Gelfand spins his piece under the table where even he can't see it.


What are the most commonly used open digital formats for chess games?

The most used is PGN.

You can arrange them in a database once you have enoguh PGNs to make it worth it. If you have money, ChessBase is great. If you want a free option there is SCID vs. PC (SCID for Linux)

Some links:

http://en.wikipedia.org/wiki/Portable_Game_Notation
http://shop.chessbase.com/en/products/chessbase12_download
http://scidvspc.sourceforge.net/
http://scid.sourceforge.net/

Note :

SCID vs PC is better than the Windows version of SCID. My opinion of course.


Demystifying Seirawan-Kasparov 1983 king and pawn endgame

In this game Kasparov is showing a perfect demonstration of the triangulation technique in order to Zugzwang the white king.

To be in a Zugzwang means, any move loses or more generally, worsens your position, and one cannot simply pass the turn and maintain the position.

In the diagrammed position, the key idea to spot is that white would be in Zugzwang if it was their turn to move. Let's see how by playing the position
assuming it's white's turn again after 47.f5:

 [title "(1) Same position as in the question, but white to move"]
 [fen "8/8/5p2/p1k2P1p/Pp2P2P/3K4/8/8 w - - 0 1"]

 1.Ke3 {only move giving us some resistance} (1.Kc2 Kd4 {e pawn falls and black wins}) (1.e5 fxe5 2.f6 Kd6 {black's in time and wins}) (1.Ke2 Kd4 2.Kf3 b3 {b pawn promotes}) b3 (1...Kc4 2.e5 {and white draws}) 2.Kd3 Kb4 3.e5 Ka3 {last key move, stopping white's king from preventing b2, and black promotes first and with check, which wins trivially.}

Having spotted the winning idea when it's white to move, next comes the question of how to achieve this Zugzwang position?
Essentially, black needs to find a way to pass the turn, that is, intentionally lose a tempo in order to have the same position but it being white's turn. This is called the triangulation technique.

Before unraveling Kasparov's triangulation plan, let's have a typical triangulation exercise:

Triangulation in Kings and pawns endgame:

In the diagrammed position below, black has the opposition as it is white to move. One sign that triangulation might be possible to achieve is to realise that one king has fewer squares than the other one. Here, black has only 2 squares d7,c6 in order to stop the advance of the c pawn and shoulder the white king simultaneously, while its counterpart, the white king, has 3 squares d5,e5,d4. So to pass the turn, the triangulation goes as: 1.Ke5 Kc6 2.Kd4 Kd7 3.Kd5 and mission accomplished: white has the opposition now as it is black to move. The resulting  opposition is winning as black is in Zugzwang: all 4 legal moves Ke7, Ke8, Kd8, Kc8 are losing (convince yourself as an exercise).

Kasparov's triangulation:

Similar to our previous example: black has to achieve the same position but with white to move, so we need to waste a tempo and pass the turn. This immediately calls for a triangulation scheme! Its feasibility here lies again in the fact that white's king has fewer squares than black's. See the diagram below:

where green shows black's triangulation plan, red shows black's threats, and blue shows white's only available squares, since:

anything past the 4th row (e.g. white king chasing the black king) loses to the b pawn promoting,
Kd4 constantly loses to Kd6 (black has opposition and thus, wins the e4 pawn),
and finally descending to the 2nd rank (e.g. 1...Kc2) gives free access to the e5 square for black, which again loses trivially (as white cannot defend both the e4 pawn and stop the b pawn).

Therefore, white only has the c4,e3 squares, i.e. fewer squares than black's king, which means the basic requirement for a successful triangulation is met, and we should be able to reach the desired position with white to move!

Now let's see the plan in action (annotated diagram):

 [title "(3) Kasparov's triangulation and Zugzwang"]
 [fen "8/8/5p2/p1k2P1p/Pp2P2P/3K4/8/8 b - - 0 1"]
 [startflipped "0"]

 1...Kc6 2.Kc4 Kc7 3.Kd3 (3.Kd4 Kd6 {and black has the opposition and wins as Ke5 can no longer be prevented}) Kd7 {the Zugzwang is already achieved: Kc4 leads to Kc6 Kd4 Kd6 black winning, and Ke3 completes black's triangulation as we will see} 4.Ke3 Kc6 5.Kd3 Kc5 {and triangulation completed: same position we started off from but with white to move! Black wins, the Zugzwang situation was discussed in diagram (1).}

Final remarks:

What a beautiful endgame! Don't be discouraged by the difficulty of these endgames, nor misled by the simplified depiction of the triangulation scheme above. Endgames, in particular kings & pawn ones, are known to be notoriously concrete and counterintuitive. Moreover, judging whether a successful triangulation is possible, is often far from being a simple matter. For example, in the above we constantly had to make sure all the other lines for white were indeed losing and that white's best bet lied in dancing along c4-d3-e3, and only then it made sense to compare which king has fewer squares! There's no singular-universally valid rule of thumb that tells us whether a triangulation leading to putting the opponent's king in Zugzwang exists or not. There are only signs, which need to be carefully considered.

The execution of these techniques, and the conversion of such endgames can never be achieved intuitively, one mis-step and all our advantage and efforts are out the window. For instance, in the game as you showed in your diagram, 8...Ka3 is in fact the only move that wins! To improve, focus on expanding your knowledge of endgame techniques (opposition, triangulation, Philidor/Lucena positions, etc), and in practical play, in order to recognise whether a combination exists, like in the Kasparov game, the mindset generally is:

spot an idea (e.g. is it Zugzwang if I pass? like in the above game)
calculate relevant variations (see if technically the found idea is achievable, e.g. in the above: can I achieve a successful triangulation?)
Evaluate the final positions in your calculations (like we did above for all the discussed losing variations)


French defense: Key ideas on the Winawer

Since the question is posed very generally, I'll only give a rough overview of some of the more typical ideas behind the Winawer for black. I'll mostly focus on positions after 4.e5 as that is the key line allowing white to fight for an advantage out of the opening.

It must be noted that the ideas tend to vary somewhat greatly depending on which specific variation of the Winawer we consider, as there are quite different ways the opening can continue after 1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.e5, namely:

The advance variation with 4...c5,
The other advance variation with 4...Ne7,
The Petrosian variation with 4...Qd7, etc.

Let's start with 4...c5, and consider the following typical position of the Winawer, arising after 5.a3 Bxc3+ 6.bxc3:

Strategic assessment:

First of, black has willingly decided to give up their dark-squared bishop, so white has the bishop pair.
In turn, this has allowed black to damage white's pawn structure.
In particular, the pawn structure favours black in the endgame thanks to white's isolated a-pawn and the doubled c-pawns.
Although black is clearly behind in space control, the central pawn structure makes it very difficult for white to actually open up the position. The position remaining closed favours black as white has the bishop pair and is getting their pieces more effectively developed than black is able to.
Black's main two weaknesses are: the c8 bishop having no simple prospect of getting effectively developed, and the highly weakened kingside caused by giving up the f8 bishop and the inability to establish the kingside knight on the ideal f6 square, which is prevented by white's early e5.
The two aforementioned aspects are what makes the advance variation with 4.e5 favourable for white, as these weaknesses offer white a tangible and concrete edge to play with.
From black's perspective, these difficulties in parrying a kingside attack or finishing development effectively means, on the one hand, black has to be ready to opt for dynamic remedies to solve their problems, such as the poisoned g7-pawn continuation to answer white's early Qg4. On the other hand, black has to know and recognise a lot of positional combinations in order to defend against white's various attacking options. These combinations are typically in the form of very subtle manoeuvres that at first glance appear to completely undermine all opening principles.

With that, let's have a look at some of these subtleties you need to be definitely aware of when playing the Winawer. To understand their necessity, we must first develop a feel for where white's best attacking chances lie. Consider again the following typical structure, but this time after black's best move 6th move, 6...Ne7:

White has three main active continuations here:

7.a4: with the idea to develop the c1 bishop to a3 and quickly exert pressure on black's dark-square weaknesses.
7.h4: a quick advance on the kingside to either play h5 (often followed by g4) to boot black's e7  knight from the key light-square posts g6-f5. Additionally, advancing the pawn to h6 is also possible, to either damage black's pawn structure after gxh6 or to further weaken the dark-squares after g6.
7.Qg4: immediately exploiting black's weakened kingside and in particular the undefended g7 pawn.

Important typical manoeuvres for black:

To prevent an early 7.a4, black has the option to play 6...Qa5 (instead of 6...Ne7) with tempo as c3 is attacked, with the idea to block next the a-pawn with Qa4! Indeed this looks dubious at first as the queen is being used as a blockader, but in fact on top of the blockade, the black queen is also well-established for creating counter-attacks on the queenside and in the center.

After 6...Ne7, in reply to white's 7.Qg4, as opposed to the more risky lines with 7...O-O, black has the option of playing the Poisoned Pawn variation, which after 7...Nbc6 entails: Sacrificing the g7 pawn for a quicker development, queenside castling, and dynamic play:

A typical continuation is:

 [title "Poisoned Pawn Variation:"]
 [fen ""]
 [startply "13"]

 1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Bxc3+ 6. bxc3 Ne7 7. Qg4 Nbc6 8. Qxg7 Rg8 9. Qxh7 cxd4 10. Ne2 Qc7 11. f4 dxc3 12. Qd3 d4 13. Nxd4 Nxd4 14. Qxd4 Bd7 15. Rg1 Nf5 16. Qf2 {black is a pawn down but has decent positional compensation thanks to white's compromised king position, the well-established knight on f5 and the white's g2 pawn against which black can continue to mount pressure with Qc6-Qd5-Bc6.}

The Petrosian variation starting from 4...Qd7 (instead of 4...c5) looks really dubious at first since: we're developing our queen by blocking our own bishop, and even before having developped our minor pieces. But in fact, Qd7 is a really useful multi-purpose move: it prevents Bb5+ and prepared to trade the light-square bishops with b6-Ba6 and it indirectly defends the g7 pawn against Qg4. Since with the queen on d7, Qg4 can be replied with f5, a discovered defense if you will :)

And the list goes on... But you see the pattern behind these subtleties: they are all backed by highly concrete ideas and thus, far from a mere application of opening principles. These are things you need to take into account if you really want to adopt playing the Winawer, these systems are not everyone's cup of tea.

Summarised notes

Again, this was simply a rough overview, attempting to bring to your attention the kinds of positions and manoeuvres you need to get yourself accustomed to if you want to start playing the Winawer. Let's finish by summarising mostly black's trumps in the Winawer:

Black ensures the center remains closed with early trade on c3 leading to the typical pawn structure of c2-c3-d4-e5 for white and (c5)-d5-e6 for black. White has the lead in space and has the bishop pair, so it's vital to keep the position closed, unless a liquidation is possible.
The early trade on c3 gives black, statically, the better pawn structure and it leaves white with an isolated a-pawn and doubled c-pawns. Thus, typically, early liquidations towards an endgame are better for black, but of course white should not allow that.
With all of white's central pawns fixed on dark-squares, black can undermine the pawn chain with c5 and can easily mount further pressure on c3 and d4 pawns (moves such as Nbc6, Ne7-Nf5, Qb6, Qa5).
However, dark-squares can also easily be black's undoing in the Winawer, specially, if black is unable to create a clear counter-play and white manages to force further dark-square weaknesses on the kingside, then white's queen and dark-squared bishop coordination can become dominant and decisive. See e.g. Hou Yifan's instructive win against Kramnik in the Winawer, an absolute dark-square domination.
As for instance advertised in the Poisoned pawn variation, black commonly has the option of also castling queenside to finish development, and play actively.
Black's main worries in the Winawer are: how to parry the induced dark-square weaknesses, and how to complete development, in particular, the king position and the locked out c8 bishop. If white plays passively early on, and allows you to comfortably resolve these, then you'll have equalised, if not even a bit better because of the pawn structure.
Exploit white's exposed queenside in order to create counter-play by targeting white's pawns, in particular the a4 square, which if occupied by either the c8 (Bd7-Ba4) bishop or queen (Qa5-Qa4), c2 can be targeted and more importantly black prevents the a4-Ba3 setup for white as discussed earlier.
Also note that lines where white sacrifices their e4 pawn do not really work, and you need to be ready to refute them. For instance, after 1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. a3, (instead of e5), black stands even slightly better after: 4...Bxc3+ 5. bxc3 dxe4 6. Qg4 Nf6 7. Qxg7 Rg8. Similarly for 4.Ne2, which allows black to comfortably equalise: 4. Ne2 dxe4 5. a3 Be7 6. Nxe4 Nf6.
As a whole, the Winawer can be a very dynamic weapon to play for a win as it can lead to highly imbalanced positions and still bears some hanging fruits to be discovered.
As a general recommendation for learning about ideas underlying a specific opening, make sure to spend a lot of time studying games of experts of the opening you're interested in. Look into the games of for example, D. Bronstein, Y. Seirawan, T.V. Petrosian, V. Smyslov, F. Caruana and N. Zhukova.


Does FIDE have rules governing online chess?

According to an announcement on the FIDE website today, 4th January 2021,

The FIDE Council has approved a new set of rules to be applied to official online chess competitions. The document, which will be incorporated into the laws of chess, is the result of a joint effort by a dedicated task force, in which several FIDE Commissions were involved

According to Article 1 of the new FIDE Online Chess Regulations they build on the existing FIDE Laws of Chess:

Article 1: Application of the FIDE Laws of Chess
1.1 Articles 1 – 3 of the Basic rules of play from the FIDE Laws of Chess are fully applied, except Article 2.1.
1.2 Article 2.1 of the Basic rules of play from the FIDE Laws of Chess is superseded by Article 3.1 of
these Regulations.
1.3 Articles 4 and 5 of the Basic rules of play from the FIDE Laws of Chess are superseded by Articles 3 and 5 of these Regulations respectively

The new Article 3 deals with the mechanics of moving the pieces in online chess and so covers things like pre-moves and auto promotion.
The new Article 5 on completing the game is particularly interesting as it changes the repetition and 50/75 move rule to reflect the way online platforms currently operate. Here is what it says:

Article 5: Completing the Game
5.1 The game is won by the player who has checkmated his/her opponent’s king.
5.2 The game is won by the player whose opponent declares he/she resigns by pressing button “resign” or
by another method available on the playing zone.
5.3 The player can offer a draw in accordance with any method provided by the playing zone. The offer cannot be withdrawn and remains valid until the opponent accepts it, rejects it by playing a
move or the game is concluded in some other way.
5.4 The game is automatically drawn when:
5.4.1 the same position appeared for the third time (as described in Article 9.2.2 of the FIDE Laws of Chess);
5.4.2 the player to move has no legal move and his/her king is not in check. The game is said to end in
‘stalemate’;
5.4.3 a position has arisen in which neither player can checkmate the opponent’s king with any series of legal moves;
5.4.4 the last 50 moves by each player have been completed without the movement of any pawn and without any capture.

There is much more,including rules covering disconnection, and it is worth examining in detail. I have to admit that, although I'm a non-smoker myself, I find article 9.9 over-authoritarian -

9.9 Smoking, including e-cigarettes, is not permitted when visible on camera.

There is, quite rightly, nothing about eating or drinking on camera. FIDE should not be legislating on other non-disturbing behaviour in players' own homes.
Finally it is noteworthy that FIDE has adopted the more inclusive he/she, his/her


What are the dates each of the endgame tablebases were completed?

Endgame tables require enormous amounts of storage. According to this post, the 7-man tables are 140 terabytes.  The 8-man tables will be many petabytes.

Each iteration of the tablebases grows exponentially in size. Moore's Law says that transistor density doubles every 18 months.  Moore's Law is starting to falter now. But assuming it is not, the question becomes:

140 terabytes for 7 man = 20 terabytes per man 'of density units', aka 20 DU
Assume X terabytes for a 32 man.
X/20 -> number of currently available units needed
2^Y = X/20 -> Y is how many times the current density would have to double
Y * 18 = months for the doubling to occur if Moore's Law holds.

The trick, obviously, is knowing how large the final table would be.

5-man 7 Gb
(http://www.cruxis.com/chess/manual/index.html?end_game_table_base_support.htm)
6-man 1.2 Tb
(http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?tid=9380)
7-man (140 Tb)

Soooo... using no math except simple division, I decided each iteration is 100x bigger than the previous. This is conservative according to simple division from the above. This also assumes that the rate of growth is linear. That is, each iteration is 100x, and that this rate doesn't change.

The result is that the 32 man table base would consume 6.6 x 10^53 terabytes of storage. That is, X = 6.6E53 Tb

6.6E53/20 = 3.3E52 DU
2^Y = 3.3E52, Y = 179
months = 18 * 179 = 3218 months
years = 153

So, my best guess is the 153 years, lol.  I can only imagine what the error on that is.

What this really is, however, is the estimate on when the storage density will be possible according to Moore's Law. It says nothing about our ability to actually calculate the tables. But it seems logical that we'd have to be able to store the result first, so 153 years it is.  At a minimum.

This is very silly as it turns out.  So going back to the X number, 6.6E53... converting it to bytes gives 6.6E65. Converting this to bits gives 8.25E64

So to store this table requires 8E64 bits, give or take (heh)

According to this web site, the solar system is made up of 1.2E57 atoms (assuming it is all hydrogen!)

So if we store each bit as an atom, we'd require about 69 million of our solar systems, in atoms, to store the 32-man table.

I'm a computer programmer by trade. I'll get right on this.

(I assumed Moore's Law holds. This is optimistic. I assumed each iteration of the table base was 100x larger then the previous. I actually don't know. However, I am confident that the result is actually... never. We will never 'solve' chess exhaustively. Because of a lack of atoms.)


When moves are randomized, is there an inherent advantage to the player who goes first, or the player who goes second?

I once wrote a program to make random moves, had it play 1000 games, and these were my results:

Outcome                        Count  Avg. #moves
-----------------------------  -----  -----------
Draw by insufficient material    500          179
Draw by fifty-move               157          208
Draw by threefold repetition     147          164
Black wins by checkmate           75           87
White wins by checkmate           72           78
Draw by stalemate                 49          138

The sample is too small to reach a firm conclusion, but as you can see, Black actually won more games than White! (I think that was just luck.) More noticeable, though, is that the overwhelming majority of games are draws.

My hunch is that there is neither White nor Black have any advantage when making random moves. The oft-quoted first-move advantage of White is based on the notion that White has the initiative, but it is very easy to lose the initiative, and if you make random moves you are pretty much guaranteed to lose it very quickly. (Edit: thanks to MaxW's answer, I'm pleased to see that someone actually went through the trouble of simulating billions of games and found that actually White does have a very slight, but statistically significant advantage: 7.7340% vs 7.7293%).

I originally posted the table above as an answer to a different question: Of all the possible legal chess games, how many end in white win, draw and black win (assuming 50 move rule)? That answer goes into more speculation about why most games are draws, but more importantly has the Python source code in case it helps run your own simulations.


Before playing a move, I like to think I pay attention to the following :

Is some piece of mine undefended ? If a few aren't, then I should bay a particular attention to them not being forkable, with anything (by a queen, mostly). If it is the case, I might decide playing something that safens this matter.
Is my king safe enough ? All checks my opponent can administer should be benign.
Is my move achieving something ? Better have a wrong plan than no plan at all.
What move am I expecting my opponent to play ? A handful of possible moves is fine, as long as it's not “well, anything, basically”. Ideally, I see how neither of these moves are a problem to me.
Tactics : Often enough, there is about one square of interest on which both players' pieces concentrate : is this square defended enough times, by the right pieces ? (i.e. defending with a rook and a queen a pawn that my opponent attacks with light pieces is not going to help) Is the checkmate I am defending from still not working ?

Of course, once I thought enough about all of these, I'd expect not to lose any game, but 4. and 5. still leave the door open to surprises if one doesn't read variations into enough depth, “how many is enough ?” still being an open question :·)


Section 5.5 of the FIDE handbook lists the following approved clocks:

5.5. The electronic chess clocks endorsed by the FIDE
5.5.1. DGT XL (year 2007)
5.5.2. DGT 2010 (year 2010)
5.5.3. Silver Timer (year 2007)
5.5.4. Sistemco (year 2009)
5.5.5. DGT 3000 (year 2014)
5.5.6. CE Clock (year 2017)
5.5.7. KK9908 Clock (year 2017)


The Anderssen v Zukertort game in the Yamie Chess kids' math boardgame

Objectively, I think you are right that 8.Nxf7 is a somewhat weak move. But it is also an unsettling, complicating move that poses a concrete defensive problem, enough of one in fact that a (truly!) great tactician like Anderssen made a serious misstep. You are also right that the main culprit in Anderssen's defeat was 9...Ke7?, and that 9...Ke8 is far preferable objectively. So why might Anderssen have played it (besides the possibility that he may have just blundered, as all the greats have done)?

One plausible reason is that that alternative 9...Ke8 itself perhaps looked hopeless. It invites the same move as in the game, 10.Qh5, with the difference that in this line the knight is pinned. Only two moves could save it: 10...Ne7 or 10...Qf6. Each can be best met by 11.f4, and it turns out that in the 10...Ne7 line the g6 knight is lost anyway (see board below). The move 10...Qf6 (which again is an ostensibly uncomfortable move to consider, lining up the black queen against the white rook on a soon-to-be open file) does save the day and leave Black with the advantage, but only with very precise play: 11.f4 exd4! 12.f5 Ne5 13.fxg6 Bg4!. I'm going to trust Stockfish here in saying that each of those ! moves is the only one to leave Black to the better.

It's very plausible that back at move 9 Anderssen didn't see that defensive possibility materializing. He may have thought he was already lost and that not walking into the pin was his best practical chance. After 9...Ke7?, if Anderssen can just get a chance to catch his breath and run away with ...Qe8 and ...Kd8, he will be better. The only move to stop that plan is the game's 10.Qh5!, and at that point White really is just winning, as there is no way to save the knight. So Anderssen probably just threw up his hands and continued with 10...Qe8. Then, either Zukertort plays the mate that he did, or Anderssen escapes; it was already out of Anderssen's hands at that point.

[fen ""]
[White "Zukertort"]
[Black "Anderssen"]
[Result "1-0"]

1.e4 e5 2.Nf3 Nc6 3.Bb5 Nge7 4.c3 d6 5.d4 Bd7 6.O-O Ng6 7.Ng5 h6 8.Nxf7
Kxf7 9.Bc4+ Ke7?
    ( 9...Ke8 10.Qh5 Qf6!
        ( 10...Ne7 11.f4 exf4 12.Rxf4 )
    11.f4 exd4!
        ( 11...exf4? 12.Rxf4 )
    12.f5 Nce5 13.fxg6 Bg4! 14.Qxg4 Nxg4 15.Rxf6 Nxf6 )
10.Qh5 Qe8
    ( 10...Be8 11.Bg5+ hxg5 12.Qxg5+ Kd7 13.Qf5+ Ke7 14.Qe6# )
    ( 10...Nf4 11.Qf7# )
11.Qg5+ hxg5 12.Bg5#


Why is en passant possibility recorded in FEN regardless of whether there is a pawn ready to make the capture?

Easier for everybody. No need to check enpassant possibility.


In that position, 12...Qe5 is the main line since the other lines all lead to clear advantages for white. 12...Qd5 and 12...Qg6 are forced losses in short order, while 12...Qg4, even though not best, it leads to crazy lines, which I also added to the analysis. Even then, there are a thousand more lines, but I added in only some of the most reasonable alternatives. If you wonder about about a line that was not included in a tactical sequence of captures, there is probably some obvious win that you should be able to find with a little thought.

After 12...Qe5, there are only two decent moves for white, which both lead to roughly equal games, but it is still incredibly complicated: 13.Nxe6, which is the main move, and even 13.fxg7 is not bad.

I used both my database, and what it shows has been played before, and a fairly strong computer running Stockfish 11 to come up with these lines. There is A LOT of stuff here, and I do not recommend trying to memorize all of it if that is your goal, but you can play through it and just enjoy some of the tactics.

In super tactical lines like this, especially as you get stronger, many players memorize a few of the main branches of such lines, but they know that if the opponent varies from them, that there is something there, and spend more time to try to find it over-the-board. In other words, the opponent not playing the memorized line is like a big flag waving that there is something hidden there, and you have to find it.

 [FEN ""]

 1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. d4 exd4 5. O-O Nf6 6. e5 d5 7. exf6 dxc4 8. Re1+ Be6 9. Ng5 Qd5 10. Nc3 Qf5 11. Nce4 O-O-O 12. g4 Qe5 {This is the main move because the other two are bad to just losing in a few moves.} (12... Qd5 $4 13. fxg7 Rhg8 14. Nf6 Qd6 15. Nge4 Qe5 16. f4 d3+ 17. Kg2 Qd4 18. c3 $18 {And the queen is trapped. This has been played three times in my database.}) (12... Qxg4+ $2 13. Qxg4 Bxg4 14. Nxf7 gxf6 $1 (14... Bd6 15. Nxd8 Rxd8 16. Nxd6+ cxd6 (16... Rxd6 $4 17. Re8+ Kd7 18. fxg7 $18) 17. fxg7 $16) 15. Nxh8 Bb4 (15... Rxh8 16. Nxc5 Nb4 17. f3 Bf5 18. c3 Nc2 19. Bf4 Nxa1 20. Rxa1 dxc3 21. bxc3 $18) (15... Bh3 16. Nf7 Rg8+ 17. Ng3 Bb4 18. Re4 Bf5 19. Re2 d3 20. Re3 Bg6 (20... d2 21. Bxd2 Bxd2 22. Nh6 $18) 21. c3 Bc5 22. Nh6 Rd8 23. Nf1 Bxe3 24. Bxe3 $16) 16. c3 dxc3 17. bxc3 Nd4 (17... Ne5 18. Bf4 Nf3+ 19. Kg2 Nxe1+ 20. Rxe1 Be7 21. Ng3 Ba3 22. f3 Bd7 23. Nf7 Re8 24. Rd1 $16) 18. Bf4 f5 (18...Nf3+ 19. Kg2 Nxe1+ 20. Rxe1 Be7 21. Ng3 Ba3 {As above.}) 19. cxb4 Nf3+ 20. Kf1 Nxe1 (20... fxe4 21. Rxe4 Bf5 (21... Rxh8 22. Rxc4 c6 $18) 22. Nf7 Bxe4 (22...Rg8 23. Nd6+ $3 {Only move.} cxd6 (23... Kd7 $4 24. Nxf5 Rg1+ 25. Ke2 Rxa1 26. Kxf3 $18) 24. Rxc4+ Kd7 25. Rd1 $18) 23. Nxd8 Kxd8 24. Ke2 $16) 21. Nf7 Nd3 (21... Nc2 22. Rc1 Rf8 $4 23. Ned6+ cxd6 24. Nxd6+ Kd7 25. Rxc2) 22. Nxd8 Nxf4 (22... fxe4 23. Bg5 h6 24. Bf6 c3 25. Bxc3 Kxd8 26. Kg2 $18) 23. Nxb7 Kxb7 24. Nc3 $16) (12... Qg6 $4 13. Nxe6 fxe6 14. fxg7 $18 {As both Bc5 and Rh8 hang.}) 13. Nxe6 fxe6 (13... Qxe6 $4 14. Nxc5 $16) 14. fxg7 Rhg8 15. Bh6 {It is important to prevent that rook from becoming active against your king.} d3 (15... Be7 {Keeping an extra piece on g5, which may be relevant later. It also stops Nxc5.} 16. Qf3 Qd5 (16... d3 17. c3) 17. Qf7 $1 $16 {Stopping Ne5 with Rad1 next.}) 16. c3 d2 {This is the main line, but there may be room for improvement here.} 17. Re2 Rd3 18. Qf1 Qd5 19. Nxd2 {This natural computer move is new, and should leave black looking for improvements on move 16.} (19. Rd1 {This is the line that was played previously.} Ne5 20. Nf6 Qf3 21. Nxg8 Qxg4+ 22. Kh1 Qf3+ 23. Kg1 {Withe perpetual check.}) 19... e5 (19... Ne5 $2 20. Rxe5 Qxe5 21. Nxc4 Qe4 22. Ne5 $1 $18) 20. Ne4 Qe6 21. g5 $16 Qg4+ 22. Ng3 $18


Dag Oskar Madsen's (quite generous) hint:

  The last move was king takes e-eight.

And here's the full solution:

  Pawn to e-four, pawn to e-six, bishop to b-five, king to e-seven, bishop takes d-seven, pawn to c-six, bishop to e-eight, king takes e-eight.

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

1. e4 e6 2. Bb5 Ke7 3. Bxd7 c6 4. Be8 Kxe8


The side selected for castling is generally related to the openings chosen by the player.  Long castling has the following attributes:

lands a rook on a center file where short castling does not.
takes more time since an additional piece must be moved (the queen).
leaves the pawn on the a-file undefended.

Finally, when the players castle on opposite wings, the game is less likely to be a draw - the opposing pawns can become purely offensive weapons.

Since Houdini is rated probably close to 1800 points higher than I am and because we don't have any specifics, I can't tell you why it's making its castling choice.  But it does not move based upon the weakness of its opponent, per se - it is making moves based upon board position.

You'll might see Houdini castling long if it has time to get the queen off the back row. Or perhaps if it can gain a tempo by castling long and hitting an opponent's piece in the center.


Does this rook endgame have a name or known original analyst?

I've looked in several books, including Nunn's earlier edition of Secrets of Rook Endings (1992), Muller and Lamprecht's Fundamental Chess Endings, and Silman's Complete Endgame Course.

None of them have give it a name or source, although Silman refers to it as a "Lucena" but notes that it's not a true Lucena, since it's a rook pawn. It does tend to get grouped together with the Lucena and Philidor positions and the bridge and Karstedt maneuvers.


Best opening in blind simultaneous chess

Generally, the simul-giver needs to keep the games as different from each other as possible. That means the opening themselves are less important, as long as they are different openings.

The simul-takers can cooperate with each other; I recall the following story from Tim Krabbé's website:

  It made me think of a story. A grandmaster once played a 10-board blind simul somewhere. Knowing the ropes of blind simuls, he varied his games right from the start, maybe opening two with 1.e4, two with 1.d4, one with 1.b3, and so on. To his suprise, all of his opponents played 1...b6. On the second move, five of them played 2...Bb7, and the other five 2...Ba6. On the third, three of the five players who had played 2...Bb7 now played 3...Bc8 and the other two played 3...Ba6, while three of the five who had played 2...Ba6 now played 3...Bb7, and the other two 3...Bc8. On move 4, the grandmaster saw bishops everywhere. After move 5, he excused himself and went to the toilet where he was happy to find a window big enough to let him through.

  I would assume anything slow would be disadvantageous to the blind person.

That makes sense, because there are more pieces on the board. However, if those pieces occupy 'normal' positions, that's usually easier to remember/visualize (from my personal experience, which is limited to a single blindfold game at a time). So if you're taking part in a blindfold simul, and don't want to 'cheat' like in the above story, play a 'weird' opening.


In the Berlin Defence, why is 4.0-0 prefered to 4.Nc3?

In a comment that ought to be an answer, @Ellie said: “The transposition from the Berlin Defense (1.e4 e5 2.Nf3 Nc6 3.Bb5 Nf6 4...) to the Four Knights Game (Spanish variation 4.Nc3) is a perfectly valid one, but the four knights game is known to be a quite dry opening for white, as in there are various easily equalizing lines for black, starting from the Rubinstein 4...Nd4 (see Kramnik games). Instead 4.O-O is the more critical line (one that offers more hanging fruits...) alongside the 4.d3 line which is known as an anti-Berlin approach.”


analyse and store a annotated game by stockfish in scid

In the Game menu, there's a Save: Replace Game option.  If you choose this after doing your analysis, the analysis should be saved.


Did any other language than English ever use Descriptive notation? Which languages have always used Algebraic?

Originally there was ONLY descriptive and it was used in ALMOST ALL languages, if not actually in ALL of them.

Each language used the letter from their words for the pieces to use to describe moves.

EG  Spanish would say AxT  for Bishop takes Rook
French and other languages used their words to identify the letter for the pieces.

I never saw Russian magazines using algebraic before it became the standard but they may have been part of the movement to transition away from descriptive. Can't speak to Russian books as I never had any of those.  And  I am positive that if you go back far enough that descriptive was the only method used.

And I never saw algebraic used anywhere until long after the 50s.  Not sure when it became popular but it did take a while to displace descriptive and really needed FIDE to make it happen.

Michael West noted elsewhere a German book for Carlsbad 1923 and said he had no problem playing through the games.


The problem with e5 is that after 6.Bb5+ white will be able to play the manoeuvre Nf5-Ne3 which will result in an iron control of the d5-square. (Without Bb5 the knight on f5 could be taken by the Bc8).

The difference to the 5.f3 line is, that f3 doesn't control d5, so when the knight lands on f5 the counterstrike d5 will be possible.

[fen ""]
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e5?! 6. Bb5 Bd7 7.Bxd7 Qxd7 8. Nf5


What are good openings for bullet chess?

The best bullet players can and do play standard openings.  The openings are theory because they are the best moves.

If you want to play something different, there are a few justifications.  If you play certain moves all the time, you can often make the moves faster and gain time on the clock.  Similarly, if you play something off-beat, you will most likely know some plans from the position and often have a better understanding than your opponent.

With that lead in, one of the simplest openings to play is to fianchetto both bishops, play e3 and d3, and bring the knights to d2 and e2 (not necessarily in that order).  There is very little going on in the first 8 moves, so you won't have to look hard for tactics.  The downside is that you give your opponent a large space advantage.

The main plans of this opening are to develop all of your minor pieces and then decide to play either c4 or f4 depending on how your opponent has deployed his or her forces.  You can castle (usually kingside) and then just play chess.

Personally, I have always had better success in online chess (especially bullet) playing standard openings.  Play openings that you are comfortable with, and you will be able to take advantage of your whole sum of chess knowledge, as opposed to just utilizing bullet "tricks".

While it is beyond the scope of this question, one of the best ways to improve at bullet is to work on playing better and faster when both players have 10 seconds.  Most games are won or lost in this time frame.


There is no symbol for a draw offer. Just add a comment {draw offered}


Reading PGN files using thr Stockfish engine

Stockfish is an engine that's called by apps that read PGN files, it doesn't read the PGN data itself.

There are many very good free apps that can read PGN files and analyse the games they contain using Stockfish (which is also free) and/or similar engines (mostly not free)

A lot of good free PGN reader apps that are able to call Stockfish can be downloaded and installed from SourceForge, such as

ChessX An old app but a good one

Scid The most popular app on SourceForge at the time of writing

PGN ChessBook Which comes with the requested Stockfish engine built in

If you search for "pgn" on SourceForge you should find more apps, but in my opinion these are the best ones currently available.


Is a gambit still a gambit if it's calculated through to the end?

No, it's not a gambit; a gambit is 'just' a sacrifice which is part of (well-known) opening theory, nothing more, nothing less.
But, technically, what you describe is not even a real sacrifice, but a 'sham sacrifice'.
Wikipedia gives the following definitions:

Real versus sham
Rudolf Spielmann proposed a division between sham and real sacrifices:

In a 'real sacrifice', the sacrificing player will often have to play on with less material than his opponent for quite some time.
In a 'sham sacrifice', the player offering the sacrifice will soon regain material of the same or greater value, or else force mate.  A sham sacrifice of this latter type is sometimes known as a pseudo sacrifice. (Rudolf Spielman, "The Art of Sacrifice in Chess", 1995, Dover, ISBN 0-486-28449-2)

In compensation for a real sacrifice, the player receives dynamic, positional, or other non-material advantages which he must capitalize on, or risk losing the game due to the material deficit.  Because of the risk involved, real sacrifices are also called 'speculative sacrifices'.

If the name 'sham sacrifice' sounds too negative to you, just call it a 'tactical combination'.


It is good to think more concretely here. After move like e5 three things can happen. White can take on e5, white can play d5 or black will one day play exd4 himself.

Taking on e5 never wins a pawn and creates a hole on d4. For good reason not very popular
With d5 your bishop is now bad, but the position for black is good, easy and funny to play. An attack with f5 f4 g5 h5 g4 Ng6 Nh4 is very dangerous. Bishop often joins the attack in later stages from h6 and is often use on f8 till its time to hold the queenside for a little longer. Also maneuver Rf8-f7-g7 us typical to protect 7th rank and attack at the same time. Find games of Nakamura how he murdered some 2700+ players just rolling on the kingside.
Tactics say it is not so easy for white to achieve exchange on d4 under good terms. After 7...Nc6 there are no useful moves for white and pressure against centre is already too strong. Popular d5 goes to (2) and Be3 runs to Ng4, even if it is also variation.

So there are three good scenarios for black after e5 and in comparison to some Maroczy bind or benoni structure I think they are both better and more interesting to play.

Note1: Many c5 style players play c5 already on move 2, by the way.

Note2: Calm players with no intention of attacking don't play kings indian in the first place, playing Nimzo Indian, Slav etc...

So everybody wants to play e5 and win!


The Chess Programming Wiki is a good place to start .  As you will quickly find out, it's a rather large and complex problem space, with many challenges (conceptual as well as actual programming).

There are plenty of open source engines out there which you could look at, to learn, or even to integrate into your engine.  I think you'll generally find that these are released under the GPL, which means you are going to have trouble making using them commercially (you would have to release your own code under GPL, if you made use of a GPL engine).

If you're aiming to have a chess engine that plays at a decent level (say, 1500+), my advice would be to try to find an existing engine to use; unless you have large amounts of free time, and you are expert in programming (preferably with some background in AI). This question on StackOverflow lists several chess engines which are released under more permissive licenses.


Which chess website with the most correct online rating?

How do you define realistic for chess ratings? Actually, they are all realistic. Ratings should be considered inside their own population because your rating in server X is your performance relative to other players in the same server. As it depends the population you shouldn't compare one rating to another rating in another server. But if you really want to compare your rating to another population approximately, please see this method: How does Chesscube.com rating compare to USCF and FIDE ratings?

All chess rating systems follow almost same rules, but they have different converging speeds. This is what you explained in your question, one server gives less on win and takes less on loss, another one gives/takes more etc.

There is a thing, K-factor, in USCF rating system for example, to tweak this converging speed from game to game. Please see this topic: What does "half-K" mean in the USCF tournament rating system?

When you enter a rating population as a new player, you start with average rating of that population(generally). But it doesn't matter which rating you start with, even if you start from 3000, you will converge to your real rating as you play games. So, it's not about being realistic again.

And generally for all rating systems, your first 8 to 20 games will have super high converging speeds, to approximate your rating faster. After that, converging speeds drops to normal and ratings get stabilized.

So, shortly, your ratings will be different in different populations, and it's totally normal.


Here you have some more information about Elo system that maybe it's useful for you.

Arpad Elo designed his system assuming a normal distribution in the results achieved by the players with a standard deviation of 200 rating points. So he used a logistic function to calculate the expected results by a player. The actual function (actually a table is used with minimal differences with this function) is:

WEa = 1 / (1 + 10^((Rb-Ra)/400)), rounded to two decimal digits

WEa is the expected result for player a, while Rb and Ra are the ratings of both players. As you can see in a game between two players having 400 points of difference in rating the chances of winning the game are 10:1.

After the game(s) expected and actual results of a player are compared, so players performing better than their expected results increase their ratings, and players performing worse decrease them. To do that the difference between expected and actual results is multiplied by a constant factor K. This constant value has to be small enough to make the system stable and avoid reflecting the very last results only, but large enough to be able to track players evolution. I guess a good value would be between 20 and 30, Jeff Sonas for example suggest 24 as the optimum value, while FIDE handbook points that rating stabilizes after 70 games (K10), 35 games (K20) and 18 games (K40), maybe these numbers can be useful for you to set your own K value.

Using a greater K value the very first few games can help your students to reach an approximate rating quickly and then you can change to a smaller K value.


The mere act of touching one of your pieces obligates your opponent to capture it (if legally permitted) on his current move (at least according to USCF standards), unless he explicitly declares his intent to adjust the piece beforehand. Assuming the clock continued running on your opponent's time and he did eventually choose how to capture the knight, I suspect that what he did would be considered legal (though somewhat unorthodox). However, if he didn't end up properly capturing the piece after touching it and before punching his clock, you would've unquestionably been justified in complaining to the official arbiter.


ChessBase: how to efficiently use two reference database simultaneously

Is there a way I can easily use both reference databases when in a
  board?

The obvious way is to create a new database by merging MegaBase and your correspondence database and use this new database as your reference database.


Are there illustrative examples where a conventionally "bad bishop" leads its side to a win?

My understanding is that we call a bad bishop a "big pawn" especially in the endgame to emphasize the fact that the bishop cannot be considered a full piece in these situations. It can't move much. It is very passive. Having such a bishop is a long term handicap.

You are right, these situations can also occur earlier in the game, but there is always a hope that a passive bishop can be traded or become more active when the position opens.

For instance, in the Dutch Stonewall, the Bc8 is a bad bishop but you can try to trade it by playing Bc8-d7-e8-h5 or via a6 in some cases. Having such a bishop earlier in the game is a handicap, but calling it "big pawn" would be too definitive, the bishop can live again!

*"Occurrences where bad bishop was more significant to victory than a good bishop?"

In the early stages of the game this is very possible and I'm sure we could find examples in the Dutch Stonewall or in the French defense where the Bc8 wins the game. In the endgame, I guess this will only happen if the opponent makes a mistake to turn a bad bishop into a winner.

Here follows an example, where the bishop in e6 is a "big pawn". White could have taken advantage of that and won the game. But in the end, after White's mistakes, the "bad" bishop wins the game!

[Title "Max Euwe vs Vera Menchik, Hastings 1930/31"]
[fen "6k1/1p3ppp/4b3/2Pp4/8/4P1P1/B4PPK/8 w - - 0 1"]

1.Kg1 Kf8 2.Kf1 Ke7 3.Ke2 Kf6 4.Kd3?! (4.Bb3!! {Dvoretsky} 4... Ke5 5. f4 Kf5 6. Bd1! {arriving just in time to cover the g4-square} d4 7.Bc2+! Kg4 8.exd4 Kxg3 9. Ke3 f5 10. Bd1 Bd5 11. Bf3+-) 4... Ke5 5.g4 g5! (5... Bxg4? 6.f4 Ke6 7. e4 Ke7 8. Bxd5+-) 6.g3 Bxg4 7.f4+ gxf4 8.gxf4+ Kf6 9.Bxd5 Bc8 10.Bf3? (10.e4!?) Ke7 11.Kc4 Kd8 12.Kd5 b6! 13.c6? (13.Bh5=) Kc7 14.Ke5 Be6 15.f5 Bb3 16.Kf6 b5 17.Kg7?? (17.e4!=) b4-+ 18.Kxh7 Bc2 19.Kg7 b3 20.Bd5 b2 21.Ba2 Kxc6 22.f6 Kd6 23.e4 Bxe4 24.Kxf7 Bd5+! {The "bad" bishop in action!) 25.Bxd5 b1=Q 26.Kg7 Qg1+ 27.Kf8 Kxd5 0-1


Dvoretsky's Endgame Manual vs Fundamental Chess Endings

They are both great, I agree that you should get both.

Dvoretsky's Endgame Manual is perhaps more instructive since it has slightly more explanatory text and tries to organize the material around rules for reader to learn, while Fundamental Chess Endings has more examples in about the same number of total pages. They both focus on practical examples from real games with very few pieces left.

In the end it's not the books you buy, but the work you put in, that matters.


According to wikipedia:

  En passant (from French: in passing) is a move in chess.

As far as i can find, 'In passing' is the translation of the name of the move, however it is not actually spoken as 'en passant' is used instead.

One explanation for the appearance of this term is that Lasker, the author of the book, accidentally translated the word. According to this page, the original form of this manual was written in German, and Lasker re-wrote it in English at a later date. He may have translated 'En Passant' into English by mistake, not realising that we also use the french for the term.

  In 1926 Lasker wrote Lehrbuch des Schachspiels, which he re-wrote in English in 1927 as Lasker's Manual of Chess.


Looking for way to “punish” the d5 push after 1. d4 Nf6

If you're a Benoni player, there's nothing wrong with 2... c5, which will get you in familiar territory (3. dxc6 e.p. is harmless and not something White wants to play - exchanging a center pawn for a flank pawn).

While it's not a great move, Black isn't immediately better, just about equal. So it's dangerous to try to 'punish' this move, especially if White has probably more experience with this line than you (and less with the main Benoni/Benko lines).


Export KPvK endings positions (up to black/white symmetry) from ChessBase 15 using python-chess

I used the following python script using python-chess library :

import chess
import chess.pgn

def KPvK_up_to_symmetry_export_to_FEN_func(pgn_file_path, nb_games, output_pgn_file_name):
    output_pgn = open(output_pgn_file_name,"w+")
    games = 0
    pgn_file = open(pgn_file_path, encoding="utf-8-sig")
    while nb_games == 0 or games < nb_games:
        game = chess.pgn.read_game(pgn_file)
        board = game.board()
        has_wanted_position = False
        wanted_fen = ""
        for move in game.mainline_moves():
            board.push(move)
            fen = board.board_fen()

            nb_p = fen.count("p")
            nb_P = fen.count("P")

            nb_n = fen.count("n")
            nb_N = fen.count("N")

            nb_b = fen.count("b")
            nb_B = fen.count("B")

            nb_r = fen.count("r")
            nb_R = fen.count("R")

            nb_q = fen.count("q")
            nb_Q = fen.count("Q")

            nb_k = fen.count("k")
            nb_K = fen.count("K")

            no_pieces = ((nb_n == 0) and (nb_N == 0) and (nb_b == 0) and (nb_B == 0) and (nb_r == 0) and (nb_R == 0) and (nb_q == 0) and (nb_Q == 0))

            cond = ((nb_k == 1) and (nb_K == 1) and (nb_P == 1) and (nb_p == 0)) #KPvK
            cond_symmetrical = ((nb_k == 1) and (nb_K == 1) and (nb_P == 0) and (nb_p == 1)) #KvKP

            #cond = (nb_B == 2 and nb_b < 2)
            #cond_symmetrical = (nb_b == 2 and nb_B < 2)

            if ((cond or cond_symmetrical) and no_pieces):
                has_wanted_position = True
                wanted_fen = board.fen()
                break
            else:
                continue
        #We are out of the loop on game moves, with a FEN or with nothing (if the game hasn't the ending we want)
        if (has_wanted_position):
            for header_key, header_value in game.headers.items():
                output_pgn.write("[" + header_key + " \"" + header_value + "\"]")
                output_pgn.write("\n")
            output_pgn.write("[FEN \"" + wanted_fen + "\"]")
            output_pgn.write("\n")
            output_pgn.write("\n")
        games += 1
    output_pgn.close()
    return None

nb_games_total = 1523849
KPvK_up_to_symmetry_export_to_FEN_func(r"C:\CHESS\PYTHON\megadatabase2020.pgn", nb_games_total, "megadatabase2020_KPvP.pgn")

I did this for the pgn file I got from chessbase by exporting to text PGN my whole megadatabase 2020. Executing this script will produce a pgn file containing positions, that I'll be able to use back in chessbase.