Should I go for the Traxler Counterattack?

The Traxler can be a lot of fun to play if white plays 5.Nxf7?!.  If white plays 5.Bxf7+! instead, then it's a lot less fun.

Before I go any further, let me recommend the following: instead of the Traxler, play 4...d5 5.exd5 and now either 5...Na5 (Morphy variation) or 5...b5 (Ulvestad variation).  Both of these lines feature black sacrificing a pawn in exchange for quick development.

Now, back to the Traxler:

First, the "fun" line, 5.Nxf7?!.  Black should play 5...Bxf2.  Now white can choose between Kxf2 and Kf1.  Both of these lines give black good attacking chances, although black will frequently be down two pieces.  You can take a look at an article from chesscafe for some more information.  Those lines are not really up to date, but it's a good introduction.  If you're interested in these specific lines, that's probably worth a separate question for each since the variations get out of hand very quickly.

The more sobering line, 5.Bxf7+ can really put a damper on black's plans.  The best line now is 5...Ke7 6.Bb3! Rf8.  Now white scores an impressive 69.3% with 7.d3.

Granted most of those games were not top level games, but black's difficulties are apparent.  White has not committed to castling kingside yet, and can start trades with a plan like Nc3-d5.

So to wrap up, if you want to play the Two Knights defense (3...Nf6), you have to be ready for 4.Ng5, and you should take a look at the Morphy variation and the Ulvestad.  Both of these lines give black good chances for a win, even though black sacrifices a pawn.  Playing a quiet move like 3...h6 or 3...Be7 is not really good, although both moves stop 4.Ng5.  The problem is that neither h6 nor Be7 really help black develop around the center, and white can react immediately with 4.d4!.

At the top level, black will usually play into an Italian game with 3...Bc5 instead of the Two Knights.  The only real gambit in this case is the Evan's Gambit with 4.b4.  Again, all of these variations probably deserve their own question, but hopefully this is enough to get you started.


Steps to checkmate in my endgame position

Black mates in three with

[FEN "8/8/8/4k3/bq6/8/8/2K5 b - - 0 1"]

1... Qb7 2. Kd2 Qe4 3. Kc1 (3. Kc3 Qd4#) Qc2#

The paradoxical Qb7 is the only solution, you can check this with an endgame database.


Which is better for an improving amateur to play even better: correspondence chess or faster time controls[both online]?

Correspondence chess will do more to improve the quality of your game. That is, your moves will be a lot more thoughtful and deliberate, and so will your opponent's. When you lose, it will probably be due to a subtle mistake beyond your ordinary comprehension (have better players point out where and why you lost).

That said, "fast" games may do more to improve your playing strength. There will be times when you will "under the gun" and make "stupid" mistakes under time pressure. In the short run, at least, minimizing such mistakes will do more to improve your rating.


What to study after someone stopped playing for years?

Having had experience with this exact problem myself a while back, there is only one advice that I can give: play as much as possible! If the time management issues you're describing are a new occurrence they are most likely due to you being rusty, and they should be corrected by regular tournament play. It takes time to reinstate the trust you had in your own in-game judgement after a long period of inactivity, but it will most likely come back if you keep on playing regularly.

As a final note: studying chess theory is never a bad idea if you're looking to improve, but don't expect it to fix your problems with time management.


Static exchange Evaluation (SEE) optimization

Your algorithm seems very wrong to me for SEE. It appears much closer to Quiescence Search instead.

SEE is an unary tree. After finding a legal move, the SEE function returns. It doesn't need to check all possible moves for the best one; just one.
You sort your moves in MVV/LVA order. Your ordering should just be on the least valuable attacking piece.
You search all possible moves. SEE only searches captures on a square.

To answer your question of:

  what to return "in check"

SEE doesn't actually care about check. If you capture with your king and the opponent can capture with anything, then the value of the king should be large enough that Math.max(0, evalPiece(foo.captured) - _see(sq, tfen, depth + 1, maxDepth, -color, chess)) has a greater score for not capturing with your king than capturing the king.


Why is this position stalemate? I'm new to chess

Black is not in check (which would make the position checkmate) but black has no legal move. This results in a type of draw known as stalemate.


Feedback and advice on a slav position for White

After 4.cxd5 the Queen cannot take because of 5.Nc3 Qa5 6.Bd2 which renders black in a horrible game (Stockfish says +1.4).
So black has to play 4.cxd5 cxd5 5.Qb3 which either wins the pawn on b7 or forces black to play Qd7 (or Bc8)
[FEN ""]
1.d4 d5 2.c4 c6 3.e3 Bf5 4.cxd5 cxd5 5.Qb3 Qd7 6.Nc3 e6 7.Nf3 Nc6 8.Bd2

However, this is 0.0 or maybe +0.1. So it is not desirable for White. Instead, I advise you to play 4.Bd3
[FEN ""]
1.d4 d5 2.c4 c6 3.e3 Bf5 4.Bd3 Bxd3 5.Qxd3 e6 6.Nf3

or 3.cxd5. Even though it is frowned upon as a Remis variant.
[FEN ""]
1.d4 d5 2.c4 c6 3.cxd5 cxd5 4.Nc3 Nc6


What are all the world chess championships (such that...)?

Where can I find an official list of world championships in chess? I mean, the one above is just wikipedia. Idk I just figure FIDE might have some list on its site somewhere.

The closest official FIDE list is in section D. REGULATIONS FOR SPECIFIC COMPETITIONS of The FIDE Handbook. There you will find many subsections specifying the regulations for all the different competitions that FIDE organises.
For most of them it is obvious whether both players qualify. For example, neither of them qualify for the various age-limited world championships for juniors and seniors (detailed in most of D.04).
Slightly more difficult is to decide whether or not a competition qualifies as a World Championship. Your mileage may vary. For example I would classify the FIDE World Cup (D.01.03) as the World Knockout Championship. It isn't classified as a world championship because many people think knockout is an unfair form of competition - too much luck of the draw.
Section D.07 has the regulations for the world open rapid and blitz championships and D.08 for Fischer Random.


Peter Svidler explains this in his excellent video series and e-book on the Grünfeld (Premium access only).

The point is the initiative. This move discourages black from playing 11...cxd4, because that would lead to a very uncomfortable situation for black: After 12.cxd4 Qxd2+ 13.Kxd2 O-O 14.d5 Rd8 15.Ke1, there is no good square for the knight. 15...Na5 is now impossible, because the bishop can go to b6.

And this is the reason why Svidler follows Avrukh's recommendation to play 11...Bg4 in this case.

[ECO "D85"]
[Opening "Grünfeld Defense: Exchange Variation"]
[FEN ""]

1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7 7. Be3 c5 8. Nf3 Qa5 9. Qd2 Nc6 10. Rb1 a6 11. Rc1 cxd4 (11... Bg4 { Recommended by Avrukh and Svidler } 12. d5 Rd8) 12. cxd4 Qxd2+ 13. Kxd2 O-O 14. d5 Rd8 15. Ke1 Nb4 (15... Na7 { Best move according to Stockfish. Has never been played. })  (15... Ne5 16. Nxe5 Bxe5 17. f4 Bb2 18. Rc2 Ba3)(15... Na5?? 16. Bb6!) 16. Bd2 a5 17. a3 Na6 *


software to analyze my own database of games with statistics

There are quite a few programs - commercial (Chessbase, Hiarcs) or free (ChessX, Scid, Scidb, ChessDB, Arena). More or less, all will provide what you need.

I personally prefer ChessX (under MacOS and Windows) using the following steps:

Open your database
Select Menu View->Players which enables the player explorer
Filter the games for your own name

You will get a statistics for each ECO code played with White or Black.
Now you can tell, which ECOs provide good or poor results. If you need further details or statistics, you can create a ticket on ChessX homepage.


This is a good question, because equality in chess is a tricky concept.

From a theoretical point of view there are only three evaluations of position: "White is winning", "black is winning" and "it's a draw". So, when we talk about white being better or black having a "slight pull", these evaluations are heuristics that mirror our experience of who is having the better practical chances and by what degree.

This also means that evaluations of the same position by different players can be quite different and often it is difficult to decide who is "more right".

So, when an author declares, that black has equalised, he means that he considers black's chances to not be worse any more. This doesn't say anything about the nature of the position. For example some GMs would argue that in the king's gambit, after 1.e4 e5 2.f4 ef black has already equalised. But obviously the position isn't drawish in the least, there is still a big fight ahead.

The idea that "trying to equalise first" is the same as "playing for a draw", comes from the fact, that it is often easiest to equalise by careful simplification. So there is a slightly artificial dichotomy between "trying to equalise first" and "going for a sharp fight". I call it slightly artificial because nowadays, especially among top players, the easiest way to equalise is often to go for the sharpest, most forcing lines.

As for what you should do: In my experience you should always try to develop counterplay, even if you are completely happy with a draw. If you can create even a slight initiative it is usually not difficult to exchange into a completely equal and drawish position. Whether exchanging queens should be your goal, depends entirely on the position.

In the end, how much risk you take is completely your decision. Some players try to go for the win straight away, even with black. Others want to play with the draw in hand, especially with white.


I really don't know how to calm myself and it might be effecting my play
Many people feel this way, e.g. becoming excited after winning material, or becoming upset when we slip from dynamic equality to a losing position.
To paraphrase IM Josh Waitzkin, who has a tutorial called The Psychology of Competition in the Chessmaster program:

Change your biochemistry to bring you back to the moment, e.g. take a break from the game, wash your face, or jog up a flight of stairs
Don't feel positively or negatively about previous positions. Stay objective and focus on just the position in front of you, rather than the preceding events. This is what a computer does

Chess I think is probably bad for my health
I'm not a doctor and I can't advise you on your health. If you feel that it is impacting your health, see your doctor. After all, your health is more important than playing chess.
Maybe its about time I just quit chess all together
Before you consider quitting chess, I would advise that you try a different, slower time control. I dislike blitz because I just don't have the time to play at the level that I would like to do.
Also, you may want to consider what it is that motivates you to play chess. Is it:

The competitive element?
The feeling of self improvement?
The artistry of the game?
Social engagement?
Something else?

If you don't feel motivated to play, then there is no need to force yourself into it.
Summary

What you feel is very common. Try to train yourself to remain objective when playing chess
If you feel the game is impacting your health, see a doctor
Reassess what you want from chess. If it isn't providing what you need, consider trying a different hobby


Where can I find a list of tournaments to participate in?

For US tournaments, I recommend checking the U.S. Chess Federation (USCF) website:

http://www.uschess.org/tlas/upcoming.php

For non-US tournaments, I would check the FIDE website:

http://www.fide.com/calendar/tournaments.html

http://www.fide.com/calendar.html


Does playing gambits improve your tactical skills?

I think that there are important skills you can learn from playing gambits, like how to use an advantage in development and the initiative, or just the fact that material isn't everything. It's probably also useful to learn those things early on in your chess career.

I'm not sure about them being better for improving tactics though. Every chess game has tactics.


Try to understand the key idea behind the opening, and try to relate each of the main moves to it. If you can't do this, you don't understand the opening.
First test the new opening by playing it against players weaker than you (in your case, <2000). If you are getting bad results, it means that the opening doesn't suit your style. Then test the new opening against players stronger than you (>2200). If you are winning more games that usual, the opening is "value added;" otherwise it's "back to the drawing board.
If I buy a book or DVD, it's because something I've seen makes a "lightbulb" go off in my head. If I don't have this "aha" moment, I don't buy the item.
The greater your strength, the less benefit you will receive from books, and the more benefit from your own study. If you are the "smartest kid in class," you won't benefit much from reading others' papers.
Depending on the opening, mastery could take from a few months to years. Some GMs spend a lifetime trying to understand one opening.


The current world champion Magnus Carlsen needed around 15 years to go from beginner to world champion. He was probably one of the fastest ever because he started to play quite late (at the age of eight) and was the second youngest classical world champion (if I remember correctly).

He received professional training from a strong GM almost from the beginning. He played tournaments almost constantly. His parents took a year off work, to accompany him to tournaments. Due to his tight tournament schedule he didn't finish school, although it was a special sports school, where he received more chess training.

So, if you are 8 years old or younger, and you can afford to concentrate on chess for the next 10 years, you do have a shot at being world class some day.

Otherwise, not so much …

Anyway, I would advise you to go to a local chess club. Google tells me that there are chess clubs in Pondicherry. There you will find out, whether playing tournament chess is actually enjoyable for you. I believe that was a necessary step for every chess world champion.


A rook up, can black end the checks and thereby win (LiChess.org puzzle 74754)?

Looks like you are correct with your second assumption - the evaluation didn't (cannot) look deep enough.

It's a classic application of the horizon effect.

The white queen essentially has half of the chessboard at her disposal to give checks, while the black king has no shelter (the single rook is not enough (but moving it every now and then will reset the 3-fold-repetition countdown) and the black queen is cut off) but a lot of space to run around. The pawn on g5 will fall with check at some point and reset the 50-move countdown, too. The number of lines increases exponentially and since none of them actually changes anything significant about the position, Stockfish cannot efficiently prune any of them. Thus the search tree grows too large to process even for a modern engine on presumably good hardware.

PS: I've tried and removed the white pawns and the black pawn on g5 who look insignificant to the perpetual at first glance to reduce the number of chessmen to 7 - low enough to use Lichess' tablebase. And indeed, that position is won for black. However, this is meaningless as both sides will quickly play moves that are impossible in the puzzle position, e.g. the white queen will move to a1 and the black king will run towards e3.


Maximum number of pieces on board in dead position

I've come up with 23, in the following position, with promotions:

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[FEN "nb2k3/2p5/1pP5/1Pp5/2P1p1p1/3pPpPp/3P1P1B/4KNBN w - - 0 1"]

*


The idea of giving your students some guidelines for playing good chess is good in principle, but we have to be aware of its limitations too. For the "practical" ones:

1 This is great until you play a 5-minute blitz game. You also don't often need 20 seconds in a capture-recapture sequence. This illustrates the main problem with trying to create fixed rules, they don't apply in every situation. I would go for "think until you make sure you are not blundering"
2, 3 and 4 are good pieces of advice!
5 is just bad etiquette. I understand what you mean but you should definitely resign if you are a queen and two rooks down in material
6 is pretty controversial. Just say "I shall find a good plan". Anyway beginner games are rarely decided on planning but on blunder exploitation
7, 8 and 9 sound fine to me.

The "in-game" principles are generally OK, but meaningless outside of their context, sometimes even false or contradictory with one another. If you are going to present them, please do so by providing good examples of how those rules actually apply.

As a final thought, please keep in mind that it's better to let your student figure out the "in-game" principles themselves rather than you showing them as if they were the Ten Commandments. Your mission should be to give them hints in their discovery, rather than being the word of Truth. For the sake of example, let's take in-game rule No. 6. I would review one of their games where they have an awful knight, then try to help them figuring out why the enemy's attack was so devastating. Eventually, they'll see how useful the knight would have been in an active square creating counterplay


Chess apps that provide a 3D view of the board and allow export of PGN

Chess.com is probably one of the world's most popular online chess platforms. It has an app and a website (which offers many more features, such as a beta 3D view). In both, you can export game PGNs and have an efficient friends system in which you can challenge people to play. There are also many other beneficial features- free lessons from master players, tactics training, vision training and numerous drills to improve endgame play, as well as Stockfish analysis. Hope this answers your question.


16 roses, 16x16 board; maximum double-attacked squares while all 256 squares are attacked at least once?

Sopel hasn't been around for a couple of years, but his solution is pretty and worth posting.

The pink squares contain the 16 roses. Each rose attacks all the squares whose distance away is sqrt(5), 4, 3 x sqrt(2), sqrt(29), 4 x sqrt(2) or 6. A rose does not attack the square it occupies.
All the squares are attacked from 1-3 times, including the squares which are actually occupied by the roses.
Addressing the original question: 100 squares are attacked more than once, of which just 8 are attacked three times.


Amazing chess feats while in altered states of consciousness

I don't know if this counts, but here is a story (unfortunately only in Norwegian) about the former president of the Norwegian Chess Federation, Jøran Aulin-Jansson, who in his youth played blitz for 92 hours straight: http://www.nrk.no/sport/92-timer-med-sjakk-i-strekk-1.6589371

In 92 hours and 26 minutes he played 701 games and won 549 with 32 draws.

He explains how accidentally eating a rotten chicken kept him awake during the third night.

At one point he hallucinated about spiders crawling up his leg. I guess that qualifies as "altered state of consciousness".


Which countries have (or had) chess as a compulsory component of their national curricula?

In this article in the Majorca Daily Bulletin (2015), the Spanish parliament is described as having unanimously passed a resolution that year to allow regional governments to introduce chess as a compulsory or optional subject in schools. The resolution is similarly described as "non-binding" in the Financial Times.
The first-mentioned article further states that

Armenia became the first country to apply the policy nationwide in
2011. Mexico followed in 2014, as well as parts of China, India and Germany.

The word "parts" here implies that chess is not a compulsory part of the national curriculum in those countries as defined in the question. I have not yet found a fully reliable source for the case of Mexico. So far the only certain case I have identified is Armenia.
A report on the international conference on chess in schools held in Armenia in 2014 quotes FIDE's then president Kirsan Ilyumzhinov as follows:

Recently I was in Mexico. They showed me their national school
curricula [sic] and said that they were going to follow Armenia’s example
and make chess a compulsory subject in schools. The same is true for
Paraguay, Mongolia and Thailand.

Regarding Thailand, I wonder which game is being referred to. International chess is much less played in that country than makruk, also known as Thai chess.


Why is there no rule allowing a player to claim a draw in lonely king
endgames?

For the simple reason that there is no need. If you are the player with the extra material you can offer a draw and be almost guaranteed that your opponent will accept the offer. If you have an opponent who is ignorant of the rules you can walk away and let your clock time expire and the game will be a draw.
This is what the FIDE Laws of Chess have to say:

6.9 Except where one of Articles 5.1.1, 5.1.2, 5.2.1, 5.2.2, 5.2.3 applies, if a player does not complete the prescribed number of moves in the allotted time, the game is lost by that player. However, the game is drawn if the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves.

A player with only a king cannot checkmate the opponent and so the game is a draw.
EDIT: Remellion makes an excellent point in the comments which is worth repeating -

Technically you don't need a new rule - under 7.5.5, you can just make two illegal moves in front of the arbiter, ending the game immediately (as a draw, similar to when your time runs out but cannot possibly be checkmated). No need to bloat the rules more

You don't even need to wait until the arbiter is watching your game. You can deliberately complete (by making the move and then pressing the clock) an illegal move, stop the clocks, explain to your opponent that you have made and illegal move and then call the arbiter to report yourself. While the arbiter is there explain to them that you are going to make a second illegal move to effectively claim a draw. That way you don't annoy the arbiter by calling them back twice.


Knight + King vs Knight + King - Loss on time

You have three choices:

Always play with an increment, then this won't arise because you can always move within the increment
Try and fork your opponent's king and knight. Either he takes your knight or you take his knight next move - result = draw. Or the best and simplest with so much time left
Just play very fast until you have made 50 moves without any pawn moves (there won't be any because there are no pawns left) and without any captures (if there are any then the game sill be draw.)

One minute should ample time for you to just make 50 moves with your knight. Quality doesn't matter in this case.
According to the FIDE Laws of Chess:

9.3 The game is drawn, upon a correct claim by a player having the move, if:
9.3.1 he writes his move, which cannot be changed, on his scoresheet and declares to the arbiter his intention to make this move which will
result in the last 50 moves by each player having been made without
the movement of any pawn and without any capture, or
9.3.2 the last 50 moves by each player have been completed without the movement of any pawn and without any capture.

Most online servers implement this automatically. If 50 moves are made with no pawn moves and no captures then the server ends the game as a draw.


ChessPersonality.com lists the following chess styles, listed with a great player who exemplifies that style and opening recommendations:

Professional
Romantic
Surgeon
Technician
Anaconda
Assassin
Barbarian
Champion
Escape artist
Genius
Grinder
Mad scientist
Magician
Mastermind
Natural
Prodigy

Each style varies according to where players typically sit on the following spectra:

Attacking - positional play
Aggressive - solid
Intuitive - calculating
Emotional - calm


Why is it rare to see unusual "special" opening preparation by trailing player late in a match?

It happens, but there's a reason why it doesn't happen often, and, when it does, why it doesn't work.

First off, there's a psychological reason not to do it; it's uncomfortable. If the match is going badly for you, it's natural for you to fall back on familiar weapons: positions that you know how to play better than any others. When you do that, when you stand on familiar ("home," if you will) ground, you feel more secure and play better than if you're in less familiar territory. And when you play better, you're more likely to score better.

Also, there's the unknown. When you're down by a point late in the match, a single failure ends your chances. And, when you decide to divulge radically from your "normal" game approaches for this one game, you don't know with certainty how well your opponent can play those positions. So you divert time away from preparing to play comfortable positions even better than you currently play them (after all, no one plays their comfortable positions perfectly, there's always room for improvement) to learning how to play a completely different position passably well. And, when the day of the game dawns and you uncork it, you find out your opponent actually likes to play those positions, just never gets the chance to because opponents haven't so far let that happen. And down go your chances of leveling the match in a flaming crash.

Romantic notions like risking everything on one wild roll of the dice don't occur naturally to the vast majority of top chess players, because the tendency to do so keeps them from making it to the top, except in the rarest of circumstances.

A GM once told me chess was a little like tennis; "sometimes the only thing you can do is hit the ball back over the net and try to give your opponent another chance to make a mistake."

You're far more likely to see a player pull divergences like that that early in a match than late, such as Fischer pulling out 1.c4 to open Game 6 of the 1972 match (that match was for 24 games, so G6 there would have been like G3 of Carlsen-Anand). If it doesn't work, then the player still has the energy to save the draw if possible, and time to recover from the failure if not.


Playing against the 2...c5 systems in the Kings Indian Attack against the French

I will try to give a few ideas based on the limited information, and trying to follow some common sense regarding development and the moves your opponent played.

    [FEN ""]
 1. e4 e6 2. d3 c5 3. Nf3 Nc6 4. g3 (4. Be2 g6 {4...d5!} 5. O-O Bg7 6. c3 Nge7 7. Be3 d6 8. d4) 4... g6 5. Bg2 Bg7 6. O-O Nge7 7. c3 d6 8. Re1 e5 9. a3 O-O 10. b4 a6 11. Be3 b6 12. Nbd2 h6 13. Rb1 Be6 14. Qc2 *

I am not a big fan of the King's Indian Attack. Frankly, your opponent's response, which I like a lot, with an early g6 tends to really blunt the main k-side attacking premise that makes this opening fun for white sometimes, and thus, the main reason to play it. The other thing is that in this c5 variation, black always can go for the normal Sicilian "equalizing" move, d5 with little trouble.

The fact is that your second move cedes space to black from a very early stage, so it is hard to believe that you will be able to gain an advantage out of the opening. You might want to hide your intentions a little more too with 2.Nf3, 3.g3, and only then, play d3 before showing your hand. He might not play a line with g6.

As to what to do, because g6 really makes it hard to attack his king as in the main lines, the line I gave sets you up to play the re1 to d1 and the ra1 to b1 and eventually to play bc. If he opens the b-file, you will try to play on it, and you are probably better placed to use it, or if he opens the d-file, you can play for d4. If you really do not have play on the k-side, you have to look at the center and q-side.


Maximum number of ways to get out of check

Of course we can do better. We can always do better. 42 legal responses with a little trick.

[FEN "3rB2k/2P1P3/1NQ1QN2/2Q1QN2/2Q1Q3/1R3R2/3K1B2/8 w - - 0 1"]

My previous attempt, 40 legal responses:

[FEN "8/4N2R/3QQQQ1/1K5r/3QQQQ1/BB1NN2R/8/1k6 w - - 0 1"]

And 39 legal responses with a bishop check (and the position is legal, black's last move was ...h2-h1=B+):

[FEN "7k/1K6/4RN2/5QN1/B1R3QN/3Q3Q/3NQ3/4NQ1b w - - 0 1"]


If I like both the Caro-Kann and the Slav, is it a good idea to answer 1. d4 with 1... c6?

I don't think it's a good idea. Firstly, no 1.d4 player will go for 2.e4, unless they are also 1.e4 players and really, really good at playing against the Caro-Kann.

More importantly, you may like to play the Slav against d4+c4, and the Caro against d4+e4, but so far white has only played 1.d4. You lose options in case white doesn't follow up with a quick c4 or e4.

Mostly that's lines like the London (say 2.Nf3 and 3.Bf4) or the Colle (with Nf3, e3, Bd3, possibly b3 and Bb2, etc). Against both of those, black's best chance to get an active game are with a quick ...c5, but if you do that you've already given up a tempo.

So there is a downside, and zero upside.


When should you trade to prevent castling?

The problem with that move is a number of things.

You gave up the bishop pair.
His attack on your king is stronger than yours on his king, and you traded off a defender.
You have no time to go after his king since yours is threatened with mate on the move.
Already with three minors traded, his threats aside, there might not be enough firepower to attack his king with impunity.

Keeping a king in the center is only part of the idea behind keeping a king in the center. You need to be able to open more lines to attack it, and that also requires having other pieces that are already somewhat trained on the opposing king already. Once the king is stuck, you either need to be able to open lines immediately with pawn play, or an additional sacrifice. If you cannot do that, you should question the trade, and ask if you are simply trading your good piece, in this case a B with some good scope, for a worse piece, in this case a barely-developed Nd2.

In your line with 1...Bh6, your line is best play for white per the computer, and in that line, white is barely holding it together. At the end, there is 8...Rg4 9.Qh5 Bd7, and that is advantageous for black, so that is why he would want that. Black's K is quite safe on h8 there, but where does white go with his? The Qh5 is also not comfortable, and in some lines Rf4 and Bg4 are threats. White is walking a very fine line there. From there, if black can find a way to open the position just a little, the white king will come under a strong attack.

 [FEN "r1b2rk1/1p3ppp/2pp4/p1q1p1bN/P1P1P3/1PP3Q1/3N1PPP/R3K2R b - - 0 1"]

1... Bh6 2. Nf6+ Kh8 3. Qh4 d5 4. g4 Qe7 5. g5 gxf6 6. gxh6 Rg8 7. cxd5 cxd5 8. exd5 Rg4 9. Qh5 Bd7 {White is walking a very fine line here. From here, if black can find a way to open the position just a little, the white king will come under a strong attack.}


As the old poem says:

For want of a nail the shoe was lost.

For want of a shoe the horse was lost.

For want of a horse the rider was lost.

For want of the rider the message was lost.

For want of a message the battle was lost.

For want of a battle the kingdom was lost.

And all for the want of a horseshoe nail.

Exactly the same principle applies in chess. Usually the loss of the pawn results in the loss of the file, loss of control of the file allows the rooks to penetrate and the position soon collapses.


What next after 1 e4 e5 2 Nf3 Nc6 for the White tactical player?

I would recommend the Scotch Gambit. 1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Bc4! The game becomes very tactical. For example, if Black attempts to protect the pawn by playing 4. ... Bc5, 5. c3! is a very useful recourse. If Black takes this pawn, 6. Bf7+! is a tactic, after 6. ... Kxf7 7. Qd4+! Wins the piece back.

Example game (White player = Nakamura) https://lichess.org/Zny0pBLO#27


Here are a few reasons for why players use blitz games to prep for openings.

There are only a limited number of standard games (normal speed 20-30 moves/hr) that one can play. However, you can run through a lot more blitzes in one evening.
If you want to try to familiarize yourself with the positions that result from some variation, you can play a few blitzes to get the feel for it.
Blitz games serve to remind you of the standard motifs that go along with certain openings. Also, you get to see how opponents not well-versed in the openings handle your moves.
Some players try out new openings (to their repertoire) in blitzes before trying them out in tournaments.
I have encountered blitz opponents who will routinely resign after the first 20 moves or so (no matter whether or not they had a better position) just so that they can focus on the opening again. (They don't care for their blitz ratings.)

So in sum, blitzes can be of good help to the amateur, but it should not be the only preparation for learning openings.


What are some chess games that feature Zugzwang despite many pieces remaining on the board?

The game Alekhine-Nimzowitsch immediately comes to mind; a great example of both a zugzwang in a position full of pieces and the infamous "Alekhine's Gun" (the tripled major pieces on the c-file):

[FEN ""]
[White "Alexander Alekhine"]
[Black "Aron Nimzowitsch"]
[Result "1-0"]

1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. Bd2 Ne7 6. Nb5 Bxd2+
7. Qxd2 O-O 8. c3 b6 9. f4 Ba6 10. Nf3 Qd7 11. a4 Nbc6 12. b4
cxb4 13. cxb4 Bb7 14. Nd6 f5 15. a5 Nc8 16. Nxb7 Qxb7 17. a6
Qf7 18. Bb5 N8e7 19. O-O h6 20. Rfc1 Rfc8 21. Rc2 Qe8 22. Rac1
Rab8 23. Qe3 Rc7 24. Rc3 Qd7 25. R1c2 Kf8 26. Qc1 Rbc8 27. Ba4
b5 28. Bxb5 Ke8 29. Ba4 Kd8 30. h4 1-0

Nimzowitsch resigned here, as Alekhine will be able to just sit tight, making waiting moves with his king, say, and once Nimzowitsch runs out of moves with his g- and h-pawns, any piece move will spell disaster:

The c6 knight is pinned to the queen.
The c7 rook has no squares.
The c8 rook and e7 knight can't move because both are needed to defend the c6 knight.
Finally, if ...Ke8 or ...Qe8, then the c7 rook is inadequately defended after the move b5 kicks
the knight away.


Is it possible to combine CPU and GPU engines to use the other's principal variation?

This seems to be somehow LeelaFish's approach:

https://github.com/killerducky/lc0/wiki/LeelaFish

More about it here (and probably on more posts in the same forum):

http://www.talkchess.com/forum3/viewtopic.php?t=70803&start=10


Longest pondering in a standard-time control game

Tal wrote* about this game:

it was here that Uhlmann established his record, thinking over the move 12...exf5 for 1 hour 50 minutes

Judging from other comments by Tal about this game, I think the time control must have been 2 hours and 30 minutes for the first 40 moves.
[Title "Mihail Tal-Uhlmann, Wolfgang, Alekhine Memorial, Moscow Russia, 11/30/1971"]
[FEN ""]
[startply "23"]

1. e4 e6 2. d4 d5 3. Nd2 c5 4. Ngf3 Nc6 5. Bb5 dxe4 6. Nxe4 Bd7 7. Bg5 Qa5+ 8. Nc3 cxd4 9. Nxd4 Bb4 10. O-O Bxc3 11. bxc3 Qxc3 12. Nf5 exf5 13. Re1+ Be6 14. Qd6 a6 15. Bd2 Qxc2 16. Bb4 axb5 17. Qf8+ Kd7 18. Red1+ Kc7 19. Qxa8 1-0

(*) The Life and Games of Mikhail Tal, Everyman Chess (2003), p. 401.


Are there any Linux GUIs that can be controlled via command line?

Given your stated goal,

  "...a GUI that I can control via the terminal. Something where I can input a series of moves into the terminal,..."

and Student T's comment of

  "I'm not aware for any GUI that also offers command line."

I've tried to find paired items of engines that take command line moves and GUIs that will interact well with these.

Your best bet might be Crafty:
It seems that one can use command lines through “Crafty” [ref. 1] in order to play or analyze a chess game within the GUI of XBoard [ref. 2]  (which can run multiple chess variants, in addition to orthochess) – as in one enters one's moves directly via command line at terminal.

Though a very close second best bet would probably be Sjeng:
Sjeng takes command line moves (very definitely) [ref. 4], plays somewhere in the region of ELO 2500(±) [ref. 5, 6], can interface with XBoard [ref. 5], and supports multiple chess variants.

Arena (GUI) seems to be borderline sometimes.  Some indicate it to be unstable within Wine [ref. 7], some have no problem [ref. 8].

“Command-line-chess” uses a TUI, rather than a GUI, but is at least definitely command line based [ref. 9].  Perhaps one might utilize UTF-8's chess characters as a workaround? [ref. 10]

References:

https://www.cis.uab.edu/hyatt/craftydoc.html
http://www.delorie.com/gnu/docs/xboard/FAQ.html
http://www.linuxlinks.com/Software/Games/Board_and_Card_Games/Chess/index.shtml
http://www.macworld.com/article/1139946/termchess.html
http://directory.fsf.org/wiki/Sjeng
https://www.linux.com/news/chess-engines-linux
http://www.open-aurec.com/wbforum/viewtopic.php?f=2&t=6550
http://ubuntuforums.org/archive/index.php/t-377613.html
https://github.com/marcusbuffett/command-line-chess
https://en.wikipedia.org/wiki/Chess_symbols_in_Unicode


First the verdict on the posted problem. It has certainly no solution in up to 12 moves (checked by Popeye v4.79). And the author of the Gustav software which specializes in selfmates says that there is probably no regular solution to this problem.

Another expert thinks that if White simply captures everything which moves, he can then push bK over to g3 and force Black to win by h3xg2#. That's like taking a long chess problem and solving it like an regular chess game with no limit to the number of moves. Yes it will work to win but it's not really in the spirit of things. That's not to diminish his ingenious approach, but it's just not what we would consider a solution.

The good news is that this problem turns out to be a recognizable example of the Broecker schema, invented in 1891 by Gustav Von Broecker. The German PDB database contains 36(!) other problems which are all based on the same diagonal opposition of bishops. One early very clear example is the following:

    [Title "Broecker - London Chess Fortnightly 1892 - s#9"]
    [fen "kb4R1/1b6/P7/8/8/7p/6BP/6BK w - - 0 0"]

    1. Rf8 Bc6 2. Re8 Bd5 3. Rd8 Be4 4. Rc8 Bf3 5. Rh8 Be4 6. Bf3 Bd5 7. Be4 Bc6 8. Bd5 Bb7 9. Bc6 Bxc6#

"s#9" is shorthand for "selfmate in 9" - i.e. White moves first and forces an uncooperative Black to checkmate White by Black's 9th move at the latest.

As the original poster had deduced, there is a key relationship between the square of the queen (or rook) on the 8th rank, with the number of squares separating the bishops. Either player must always make them match if they can, and if he fails to, the other player gets a chance to make them match instead.

White wins because he is able to match by moving 1. Tf8 only. Black has many possible lines of play, but the longest he can hold out is 9 moves. One example solution is shown here.

In the original problem, the position is already a "match" with White to play. He is forced to break the match, and Black can always recreate it, so need never lose. It doesn't seem there is any way for White to use the additional power of the queen to change the parity.

However the matrix has proved very rich over the years, as you can see from the database, and I am sure there's more that can still be mined. The longest problem known to be sound is the following:

    [Title "Rotenburg & Trillon - Die Schwalbe 1980 - s#14"]
    [fen "k7/1b4R1/N7/7p/8/7p/6BP/6BK w - - 0 0"]

    1. Rf7! Bc6 2. Re7 Bd5 3. Rd7 Be4 4. Rc7 Bf3 5. Rh7 Be4 6. Bf3 Bd5 7. Be4 Bc6 8. Bd5 Bb7 9. Bc6 h4! 10. Bd5 Bc6 11. Rc7 Bb7 12. Rc1 Bc6 13. Rb1 Bb7 14. Bc6 Bxc6#

Again, here is a sample solution as Black has multiple choices, although White's move is unique at every point.

What's interesting about this one is that Black has a waiting move. This flips the parity, and so normally Black would be able to continue making matches, while White is breaking matches. However, White can flip the parity, by moving to the other side of the main diagonal. This can only be done while ensuring that b7 is never free for bK to enter. Either it must be occupied by bB, or attacked by wR.


How many times can the king and its surrounding squares be attacked?

Adding on to @Brian Tower's answer as anticipated, here is an improved position with 55 attacks, using double check and White's full arsenal. Black last moved a piece to e7 that White's rook captured with checkmate.
[FEN "B7/4R3/3Q1Q2/2Q3Q1/2N1k1K1/1R4Q1/1BNQNQN1/8 w - - 0 1"]

However, it is also possible for both sides to attack under the OP's loose ruleset. I have found a lower bound of 83 attacks by White and Black, with eight of them coming from the Black king itself.
[FEN "8/3Nnn2/1bnQqQb1/1r4Q1/1nq1k1qN/1R4Q1/1BNQqQB1/2K1Nn2 w - - 0 1"]

If you are wondering of all of those pawns really could have promoted, I present evidence that it is possible.
[FEN ""]

1. a4 b5 2. h4 g5 3. c4 d5 4. f4 e5 5. cxd5 bxa4 6. fxe5 g4 7. Rh3 gxh3 8. h5 Nf6 9. h6 Rg8 10. e6 Rg7 11. hxg7

Finally, just for fun, here is 88 attacks by one side in an illegal position. Any piece can be color swapped to produce a result for both sides.
[FEN "8/2NNNNN1/1NNQQQNN/1NQ3QN/1NQ1K1QN/1NQ3QN/1NNQQQNN/2NNNNN1 w - - 0 1"]


It depends on what you mean by "increments". If you are referring to something like "playing a game in 10m + 4s", then the main reason is preventing that a player with a huge material advantage (v.g. king plus rook versus king) doesn't lose on time. With the increment of 4 seconds after each move is made, the player with the advantage will have no problem winning the position. Without increment, if the advantageous player has something like 1 or 2 seconds on their clock (and provided the other player has plenty of time, or just much more than a couple seconds) they'd probably lose on time -which usually is called "getting (dirty) flagged" in games without increment.
This is a somehow famous example of an online game in which Gata Kamsky was (dirty) flagged in a 3 minutes game without increment, with just one rook and king per side.


Whose games should I collect for Scotch Opening?

I religiously play scotch in e4/e5 games. Sergei Rublevsky is the star I follow.


Do better board representations than the standard one exist?

Chess is a game in two dimensions. The game is made to be played in two dimensions. Pieces move horizontally, vertically, and diagonally very naturally on a chess board. It's purely visual and the sort of thing our brain does very well. Other depictions of the position sacrifice the two dimensional nature of the game. When this information is lost, we have to calculate to reconstruct the spacial relationships in the game. Consider the difficulty of spotting a pin or discovered check when using FEN.

In the other notations other than the standard diagram, you'll spend a lot of time doing mechanical sorts of math.

The different representations (diagram, moves, and FEN) exist because they fill different needs.


Question about solutions given in a chess book for mate-in-two and mate-in-three

I think it's slightly unusual to only give the first move, or a little outdated. But it saves space and the assumption is that if you found the right solution, you can confirm it by seeing the first move.

I also think that Polgar originally intended this book (and his other "big books") as a collection of problems for coaches to select problems for their students from, because doing 5000+ mate in 2 and mate in 3 problems is a bit much for self-study. The coaches are expected to be of sufficient strength already, and to be able to select some problems with a common theme that they need for some lesson.

The whole answer, in this case, is of course 1.Rxb7+ Nxb7 (forced) 2.Na6#.

The 'x' and '+' in Rxb7+ are strictly speaking not necessary, so some books omit it. Again, that's a bit of an outdated practice since it's just not that user friendly.


How come this king and knight + rook pawn vs king endgame not drawn?

You're confusing this theoretical endgame with K+B+P vs K.

If the bishop doesn't match the promotion square of a or h file that the pawn is on, then the pawn can not promote in your scenario.

On the other hand, the knight can go to any square on the board potentially so the h1 square can be covered by it.

I suggest going to the link below to understand how to force the king out of the corner. Ideally you should get this position with white to play, and check to force Kg8 and push the pawn.

http://www.chesskit.com/training/endgame/KNPk/1/index.php


Bxf7+ is definitely the way to go in practice in my opinion. I have done quite a lot of analysis with stockfish on Nxf7 and am not at all sure it is better for white despite the computer evaluation early on.

Bxf7+ almost certainly is a lot better for white and is a lot simpler to learn which is important for a repertoire choice against an unusual line (most people won't have the guts to play Traxler!)


Engine evaluation in endgame not increasing, what it means?

In the endgame engines will give one of three kinds of evaluation according to what they "see".

1) #31 - mate in 31. Material balance is irrelevant.

2) 0.0 - they see a forced draw. Material balance is irrelevant.

3) +2 or -1 or whatever - they don't see mate and they don't see a forced draw. They do see a material imbalance. Any concrete result is outside their move threshold and realistically any one of three results is possible. If the evaluation doesn't change much over a prolonged number of moves it shows that one side has a material advantage but can't use it to win as far as the computer can "see".

Remember computers don't have judgement. They are just calculating machines. They can only tell you what they calculate.


Quality of inputs in chess game databases?

I guess the answer is "both".

Usually (in lower leagues and opens) games are entered manually, which obviously can lead to all kind of errors. But top level games are recorded by electronic boards, which can lead to trouble if the players are moving too fast or are positioning the pieces imprecisely. And there is the constant annoyance of arbiters placing the king on the central squares to input the result, which is quite often interpreted as an actual game move by the electronic board.


How strong is each level of Atari 2600's Video Chess?

Atari 2600 has bugs which make the higher levels unrateable. It is reputed to be slightly better than Microchess, according to a chess.com article.

Atari had a very limited book which makes it weaker than current approaches.

An ESTIMATE of the strength is as follows:

Level Time Rating(?):

8        10       700

1        15       800

2        30      1000

3        45      1100

4       165      1300

5       195      1350

6       720        ??

7     36000        ??


Are there any good instructional chess videos in German with captions?

I have found this video(This Guy has a quite lot videos). It is in German, it is about Chess and you can turn the Captions on, but I think they were generated from a computer. Since I as a German guy can say, its not really, what he is actually saying, but it might help you.


Why might this supervised engine make mistakes based on an example game?

Well done for your engine. I think a positional mistake was 9...f5. It weakened the king position, and without any compensation in return. The move also seriously made the e5 square weak.

Why your engine didn't make a simpler 9...h6? Probably, your engine put too much focus onto material differences into your NN network? You'll have to spend some time on debugging. Your engine needed better understanding of king's safety. Your search depth was also too low.

I estimate FIDE 1600 for your engine.


What's next after first 5 months and 700 points?

This is an open-end question. My recommendation is join serious face-to-face tournaments where you play games at the classical time control. Playing blitz is fun, but not a good idea for learning chess.


What are weak squares in chess; how can they help to mate another player?

This is a very common example.

[FEN "6k1/5p1p/5BpQ/8/8/8/8/6K1 w - - 0 1"]

Do you see the weak dark squares around the king? Checkmate is possible because those squares are weak and can't be defended.


Which of the pawns in front of the king should be moved in order to prevent a back-rank mate?

Of course, the concrete position is always more important than general "rules". However, as some guidelines of what is typically played:

f2-f3: Rarely. It opens up a dangerous diagonal (a7-g1) and usually also the second rank (normally, the d- and e- pawns were moved early on). Even if Black can't mate directly, they can often at least kick White's king around.
f2-f4: Occasionally, to immediately counter-attack a Black center position on e5 (if the second rank can be covered through other means).
g2-g3: Occasionally. Also opens up a diagonal (a8-h1), but that can be okay if Black has no queen and light-squared bishop anymore to exploit it and/or if White can play their own light-squared bishop to this diagonal.
g2-g4 or h2-h4: Occasionally. Can make sense to grab space when there are few pieces left (the pawns get vulnerable to piece attacks) or sometimes even to launch a counter-attack on Black's king.
h2-h3: Statistically, probably the most played among the pawn moves. It creates the  smallest weaknesses on paper - but as can be seen from the many alternatives, it's by far not a move that should be played in all positions. Especially not if Black controls h2 with another piece, obviously.
No pawn move at all: The better the player, the more likely they are to try and parry the threat without actually moving pawns. Usually, moving flank pawns to open up a vital escape square for your king doesn't do anything else on the board (especially when moving to only the third rank) and can thus be seen as a waste of tempo (on top of creating structural weaknesses). Sometimes, that's a sacrifice you just have to make to prevent mate, but if there is another way (covering the checking square with a piece, blocking the way, etc.), it's often to prefer.


Most recent "best in world" player who would be defeated by a CM

McDonnell was never best in the world, and I doubt he would have been stronger than 2200 FIDE, a candidate master would be an even match. Out of the best players in the world, both Philidor and Labourdonnais would both be capable of being defeated by a CM, with regularity. It is difficult to compare strengths of the players from the past, because they would be possibly strong GM level in tactical calculation, but weak in openings and modern strategy. But I would estimate a regular 2200 FIDE CM could beat them on occasion


How can I deal with defenses I don't like?

No matter what your first move will be, you will always run the risk to encounter some openings you don't like. It's the same with endgames. At example, I do hate mating with bishop and knight, but I had to do it once to win the game. Should I have avoided that endgame or agreed to an early draw instead, just because I don't like it (and because I forget half the time how to win this bloody endgame)? Avoidance is no option, sometimes you just have to endure unpleasantness. Never throw away a game by drawing early only because you don't like the opening.

Secondly, don't play something to "punish" your opponents because they played something you didn't like. Your opponents will always try to play something which is unpleasant to you, like attacking your king and mating you ;) If you like the exchange variation of the French, then by all means play it. But if you play it just to annoy your opponent ("hah, that will teach you to play the French ever again..."), think twice. You are playing to win the game, not to eradicate the love for the French opening in the world! Only ever choose a line because it suits your goal (like getting a good position, winning/drawing the game etc.).

My suggestion is to look into the reasons of your aversion. Don't you like the resulting positions? Ask yourself why. Is it because you don't understand them or because your play is not as good in them as in other positions? Then you found a spot worth of improvement! Is it because you don't like the kind of play resulting from such positions (like too many or too few open lines, etc)? Nearly every opening offers lines to steer the game into different kind of waters. Have a look at some games of your unpleasant openings, pick the ones you would have enjoyed most to have played and then look deeper into the lines/systems that the White player employed there. In the long run, you need to hone your skills even in areas you are not interested in. For some people it's those boring closed positions, the next one can't stand pawn endgames, etc., but to become better, you have to master those situations as well. And as soon as you do, you will begin to like those situations. So this is the way to go to avoid unpleasant situations: Make them pleasant to you because you can handle them.

That said, I must say that if you are really unhappy with the openings your play produces, changing your opening repertoire might be a terrible good idea, indeed. Just don't expect you can avoid playing unwanted openings that way. Every opening move can lead to openings you don't like.


Yes black is allowed to castle here. The castling would be invalidated if one of the squares along the path the king has to cross (e8 to g8 or e8 to c8) was under attack by an opponent piece. In your position, for example if the bishop was on c7, or a knight was on e6 then castling wouldn't be allowed. Whereas the bishop on d6 eyeing b8 only concerns the rook's path to complete castling, so long castling remains legal.

Similarly, if the bishop was on e5, by the same logic short castling would still be allowed.

 [title "Position"]
 [fen "r3k2r/pp1nnp2/2pB2pp/3p1p2/3P4/2N3PB/PPP1PP1P/R3K2R b KQkq - 0 1"]

 1...O-O-O


Do chess coaches ever get disappointed with their students?

I, as a teacher of elementary age students, don't get disappointed in the students' results.  I only get disappointed if the student doesn't try.


While I don't disagree with the spirit of Wes' answer, I want to answer your question in a somewhat stronger way, one that I think goes further toward relieving any possible confusion about this issue. Your question is:

  Can a set of moves be a transposition and a variation?

My answer would be that neither transpositions nor variations should be thought of as sets of moves, and that doing so in the first place is what creates confusion here.

While particular chess openings (e.g. the Sicilian Defense, the French Defense) are often thought of as consisting of a multitude of opening lines (sequences of moves), for the purpose of making the distinction that you're after it is most useful to think of an opening as a multitude of positions (which happen to be linked together by moves). If I show you the following diagram,

and ask you what opening we're in, you know that it's the Scotch Game, even though I only gave you the position and not the exact moves we used to get there. That's because the Scotch Game can be characterized by the positions that belong to it, whatever the move-orders involved might be.

Similarly, a variation can be seen as just a particular subset of positions from one opening, ones that we've decided to give their own special additional name. We recognize each of these positions,

as being part of the Sicilian Defense. Going into more detail, we say that the first one belongs to the Najdorf Variation, while the latter belongs to the Dragon Variation. Again, we didn't need to specify move-orders at all in order to make this classification, because a variation can be characterized by a set of positions rather than sequences of moves.

A nice thing about thinking of particular opening variations as sets of positions is that it is now clearer how transpositions differ from (and relate to) variations. A transposition is an event; namely, it is what happens when a move is made that takes us from a position that is labeled as being part of one opening/variation to a position that is labeled as being part of another. Simple as that. After the moves 1. e4 d5 we're in the earliest position that belongs to the Scandinavian Defense. If White continues 2. exd5 then we're in another position that still goes by that name. But if White plays 2. d4, a transposition has occurred, because this new position is part of the Blackmar-Diemer Gambit family instead of the Scandinavian family.

In sum, an opening/variation can be seen as a family of positions that are linked together by moves, and then a transposition is just when a move leads us out of one such family and into another.


Some things that have helped me get better are:

Counter-intuitively, continue to work hard on your slow game. The best speed game players in the world just happen to be the best slow game players.  When playing slow games, you are giving your brain more "soak time" to absorb patterns and really grind into positions, giving your analysis ("I takes, he takes, ... ") skills the necessary deliberate practice.
Time Management is key.  If you are playing blitz without a time delay/increment, then it is vital to play the clock first, board second. Playing the board makes sense until you hit your time allowance per move.  Then it is a matter of playing what you consider to be best and moving on. Play what makes him burn HIS clock, not yours. You're not painting a masterpiece, you're trying to win by any means necessary! Of course, with very strong opposition, you may need to do both ... but the clock trumps the position quite often, especially as you start getting into a time-crunch! Consider reading NM Heisman's famous Two Triggers Novice Nook ... might offer you a fresh perspective if you're ever hesitating to make a move or feel nervous that you might be wrong if you rush into things.
Get Good (or at least decent) at tactics.  You should have enough tactical patterns burned into your skull to recall 1-3 ply / single-motif shots in less than 3-5 seconds. Focus on breadth (covering a ton of basic 2-4 ply tactics) and do not waste time trying to solve 12-13 ply puzzles (as most tactics servers and puzzle books tend to lure you into!)
Practice closing out won games against a full-strength computer at insanely tough time-crunch controls (for e.g. start with basics such as KQ vs K in under a minute and work your way up to piece-up/two-pawns up type of won games)
To deal with nerves or panicking, put yourself way out of your comfort zone (as necessary!) by playing a lot of online-blitz against decent opposition.  This also allows you to try out a lot of different opening lines (some of these will want to become your pet lines / repertoire) quickly.


French (white) loss to a master - where could I have improved?

11 Nxe5 looks bad to me ... White has a spatial advantage and is strongpointing d4. Nxe5 reduces the spatial advantage by allowing an exchange of knights and weakens d4. Fortunately the opponent did not capitalize correctly and played cd allowing Nxc6! but after an exchange of knights and then cxd4 I think your opening has gone wrong.

I also didn't understand why you played Qd2 and then Be2 and O-O. Why was Qd2 the most important move to play there?


Can you claim a draw, after the position has changed, if threefold repetition occurred earlier?

(I consider the FIDE rules to be the "the rules of chess" and this answer is only about them)
No, you cannot claim. In fact your right to claim ends as soon as you touch a piece.
Here's what the rules say, emphasis in bold mine:

9.2.1     The game is drawn, upon a correct claim by a player having the move, when the same position for at least the third time (not
necessarily by a repetition of moves):
9.2.1.1   is about to appear, if he first writes his move, which cannot be changed, on his scoresheet and declares to the arbiter his
intention to make this move, or
9.2.1.2   has just appeared, and the player claiming the draw has the move.

So either it is about to appear, or it has just appeared, and not at any other time.
Then 9.4 ends the debate:

9.4 If the player touches a piece as in Article 4.3, he loses the right to claim a draw under Article 9.2 or 9.3 on that move.

That's related to the touch move rule -- once you touch a piece that can legally move with the intention to move it, you have to do so. It's too late for claims.
If it were possible to claim at any later time, there would never be any reason to continue: as soon as it was clear one of the players was going to lose, they'd claim the draw.
But in the case of five fold repetition, it's different:

9.6 If one or both of the following occur(s) then the game is drawn:
9.6.1 the same position has appeared, as in 9.2.2 at least five times.

If a position repeats five times, then that's just an automatic draw, no claim needed. If it is found out later during the "game" that a position was repeated five times some time ago, then that means that you just weren't playing the game anymore after that as it was already finished. You were moving pieces about.


How does Lichess rating compare to USCF?

There is unfortunately no 'good' way to convert from Glicko-2 to ELO. While a lot of people claim they have a formula, there really isn't any system that maintains the same invariants and distribution curve when converting.

That being said, there are some ways you could try and 'convert' your score. For example, you could find people on lichess who have similar ratings to yours, and see if they are USCF rated. Also, playing in a couple OTB tournaments would be more than enough to give you an accurate sense of what your ELO rating is around.

Hope this helps!


Weak squares are squares which cannot be defended by a pawn. [1][2]
... that all of the squares behind the pawns are weak by default.
Counter-intuitively: Strong squares are squares which are defended by a pawns.

These square are very powerful places for opponents Knights or Bishops. No pawn can attack to these pieces. In below position, square d6 is a weak square for black and also strong square for its opponent.
1r1q2k1/1pbr2pp/2pNp3/p1P1Pp2/PP1P4/3R1QP1/6KP/1R6 w - - 0 1

or square f5, h4 and e6 are some weak squares for black and also f3 and d4 for white (however it's too late for black to put his Knight there)
1n3q2/p6p/1p1p1pk1/3PpN1p/4P3/1PQ3P1/P4P2/6K1 w - - 0 1

They're useful to place a Knight or Bishop in near the heart of opponents position. Usually making a weak square in the opponents land needs long term strategy. You have to force the opponent to pass its pawns...


You're absolutely right. Qe6 only seems to draw:

6k1/1p3rpp/1q1p4/p2Pp3/P5Q1/1P3PP1/2R3KP/8 w - - 3 13

1. Qe6 g6 2. Rc8 Kg7

There's no forced win for white here as far as I can see.


Sites which provide annotated openings (preferably interactive)

Wikibook Chess Opening Theory has similar aims but I don't think it quite meets all of your requirements. Still, it's the website closest to meeting them that I can think of, so I hope it helps. Being a wiki, it's still evolving and of course one can always wonder about the expertise of the authors.


2 rooks vs 2 minor pieces in a pawnless endgame

First of all I believe that this endgame must be really rare in practical games.

Playing around with the tablebase of rook+rook vs bishop+bishop, I noticed the following:

the weaker side quickly runs out of checks
the rooks cover quite some squares, leaving little space for the bishops
it is not difficult for the rook side to avoid getting pinned
with the help of all three pieces (two rooks + king) it is easy to drive the enemy king to the border
once the king is at the edge of the board, you just threaten the typical mate with two rooks, to which there is no defense really (if a bishop is placed to protect against a check from the side, you can easily win this bishop using the other rook
in many cases it also happens that you can win a bishop through a pin before the king is pushed to the side of the board

I suggest that you play this endgame against an engine to see for yourself. It does not seem particularly difficult that you would need any method. Just checking the king and pushing him to the border in the usual way is winning.

I'd expect that playing against two knights or bishop+knight should be even easier because of the shorter range of the knights.


It is the best move because it wins the knight on h4.

Black has only two squares for its queen after 1.Re4:

2....Qf3 3. Rxh4 winst the knight
2....Qg5 3. Rg4 pins and wins the queen

Note that 1. Re4 is not the only move to save the rook. White could also play Nh5 attacking the queen first and if the queen moves save the rook (e.g. via Rg3).


Rook and minor piece endgames, with pawns

These kind of endgames often occur in practice, so even if it is difficult to give hard and fast rules about them, it is well worth spending some time studying them.

The book Practical Endgame Play - beyond the basic by Flear is quite decent and spends 4 chapters (111 pages) on the endgame Rook and minor piece vs Rook and minor piece. It is a relatively easy read.

Fundamental Chess Endings by Müller and Lamprecht (as mentioned in the comments) is an endgame book of high quality, but only has 9 pages on this particular type of endgame.

Another book I like is Endgame Secrets by Lutz. About half the examples in this book feature the material balance you ask about. This book is probably aimed towards stronger players as the analysis is very detailed.


How would Chess have been played in England in 1450-1600?

I see that you already have a lot of information in the Wikipedia page and in the answer you got to the similar question in the history forum. Maybe your problem is that this is too much information for you, so I hope to be helpful in telling you just one thing, which is the most important thing.

There is a turning point in the European history of chess. This is something that happened sometime between 1475 and 1500 (the exact year is not known) in the south of Europe (probably in Spain, but there is no consensus). This event is a change in the rules of movement of the Queen and the Bishop.

Until 1475 people everywhere in Europe played a version of chess (let's call it Middle-Age Chess) where the Queen (then called fers or visir) could move only one step diagonally, and the Bishop (then called Elephant) could move two steps diagonally. The other pieces moved as today (except for little details such as castling rules). This game was very slow because the two armies needed many moves to make contact, since the only long range piece was the Rook.

Starting from 1500 people everywhere in Europe started to play a new version of the game where the Queen and the Bishop have their modern movement (let's call this game Modern Chess, because, except for some little detail, it was basically the same game we play today). This new game was much faster, and, for this reason more fun and incredibly successful. The new rules quickly spread everywhere in Europe, and the old game was soon forgotten.

The change happened sometime between 1475 and 1500, more or less the same time when many other important events gave Europe its modern form (invention of the press, the discovery of America, unification of Spain, and more).

From this you can see that in 1450, in England people played Middle-Age Chess, while in 1530 they played Modern Chess, a very different game. In 1530, Modern Chess was a novelty, instead in 1610 the game was very well established, and by this time, many "scientific" books of analysis of the game and its strategy were already written.


Is there an online database for the endgame KRPPKRP?

All of the Syzygy tablebases are available here: https://syzygy-tables.info/

These cover all endgames up to 7-man, and provide WDL (win-draw-loss) and DTZ (distance to zeroing move) data.  Syzygy also distinguishes between a theoretical win or loss that can actually be forced into a draw by the 50-move rule, and one that cannot.

Here's an example for KRPPvKRP.


How to improve positional play while keeping the initiative?

You need to realize that initiative (what you call "tempo") is only one of many factors that determine the evaluation of a position ("Who is better?") and consequently determine the best move (as you don't want to end up in a worse position after the move).

While playing aggressive attacking chess all the time might work against lower rated players; who are not that good at spotting tactics, at defending or who might be more easily intimidated by a piece sacrifice; if you play in the same style  against stronger opponents you will find that more often than not your initiative is not all that sound. Indeed most won games at higher level are not resulting from directly checkmating the king in an attack, but from converting a tiny positional or material advantage at move 62 in an endgame.

I agree that playing like Morphy is more fun than positionally outplaying the opponent, but if you want to become a stronger chess player it is essential to broaden your horizon and not focus on initiative only.

I would recommend to start with evaluating a position (from your games or grandmaster games). In order to do so, ask yourself the following questions and do this for both sides (black/white)

Are any pieces attacked?
Are there obvious tactics available?
Which pieces are well placed (lots of space to move around and attack something) and which not (little space to move and don't attack anything)?
Is the king safe? Typically with many pieces on the board you want it behind pawns on either side after castling.
Are there any weaknesses in the position such as isolated pawns, pinned pieces...?
Who owns the center?
Are there open or half-open files which are occupied or can be occupied by rooks?
Is the position open or rather closed? Who would benefit from changing it?

As you see, I did not put "Who has the initiative?" here, because in my view, the initiative is made up of several factors like more piece activity, occupation of open files, etc

Based on the outcome of this evaluation you should come up with a plan. The difficult part is how to weigh the different factors, i.e., "Is a better piece activity worth a pawn sacrifice?" Or, "I am up a rook, but my king is under attack, will I survive?) Doing this correctly requires lots of experience. However usually, in most normal positions, dealing with attacked pieces (if you lose/win material) and keeping a reasonably safe king position are the main priorities and should get the most weight, before you think of anything else.

You don't need to go crazy with this evaluation, but keeping in mind that there are more factors than initiative is a good start. You could pay attention to one point at a time to get used to it.

Also IMO, at a level of 1400-1500 studying tactics will give you a lot more benefit than thinking of positional details.


Stockfish: Engine suddenly changed the side?

The reason is very simple:

  position startpos moves e2e4 d7d6 d2d4 e7e6 g1f3 c8d7 f1d3 h7h6 e1g1 c7c5 f1e1 e8f8

This is invalid. The position before e8f8 is:

e8f8 is invalid because Black has a bishop on f8. Stockfish can't play the move, so it just skip it.

To Stockfish, the diagram position is the position it's thinking. The best move is ...cxd4.


I don't understand the central-control difference between 1. e4 and 1. e3

There isn't that much difference in strength between having a pawn on e4 or one on e3 (usually accompanied by one on d4); there are pros and cons to both (and a pawn on e3 can still go to e4, but not the other way around). The difference is between putting them there on move 1.

Let's take a look at the effects of 1.e4 and 1.e3, concentrating on the actual position. For 1.e4:

1.e4 influences d5 and f5, squares on which black might want to place a pawn. 1.e4 d5 2.exd5 gives white chances for an advantage, and 1.e4 f5?? is basically impossible.
If you want to play an opening with a pawn on e4, now is the time to play it there. It's a pawn move to an undefended square, black can easily prevent it otherwise. Observe that the most common replies to 1.d4 are 1...Nf6, 1...d5 and 1...f5, all of which prevent 2.e4.
The bishop on f1 is opened up, and it might go to the nice square c4 (in case of 1.e4 e5 2.Bc4).

For 1.e3:

1.e3 influences d4 and f4, but so what? If white wants to put a pawn there he could already do so, and black can't even legally put anything on those squares next move. So that's not relevant right now.
There is no way in the next ten moves or so that black will be available to prevent a move like e2-e3; it can be postponed until the perfect moment.
White blocks the bishop on c1. Without knowing anything whatsoever about black's setup, white basically already rules out putting the bishop on e3, f4 or g5. If you're going to fianchetto it, why not just start 1.b3. You've just made a concession before black has even played a single move!
The bishop on f1 is opened up, but it can't do much. 1.e3 e5 2.Bc4 just runs into 2...d5 (not enough control over that square).

It's fine to play an opening that involves e3 (as long as you put one or two other pawns near the center instead, otherwise you won't control anything on his half, white is supposed to be attacking), but doing so on move 1 has no advantages. That's a big difference with a pawn on e4, which can be played there on move 1 "for free" and usually only with difficulty after that.


What are the setups/patterns useful in defence?

I'm fond¹ of this one, after sacrificing my queen for some pieces and having to deal with all my additional material being forked all over the place :

[FEN "8/3P4/P2rP3/2p2Q2/8/3n4/8/5k2 w - - 0 1"]

Note that in this setup, the knight is not bound to its square, as it can move and get back to other pawn-defending squares in no time. It's a very flexible pattern. I marked these other squares with white pawns.

It seems to be a little harder to reproduce with a bishop, without blocking too many lines, and when not being the bishop+pawn one you already mention (which nicely fits on top on it, though).

¹ Also I love knights.


Is there a chess software that allows to generate and store engine evaluation graph for a chess game?

It turns out that SCID does this -
http://www.chess.com/forum/view/chess-equipment/gui-to-make-analysis-graph


I have not tried to do exactly chess set but I have some experience (really basic) with doing things from wood. I will tell what I learned from my experience, and may be someone more experienced can refine it.

Crafting from wood is not really that hard (on amateur level). You need:

material (basically wood and in the beginning almost any wood is acceptable, but not the wood you can buy for setting the fire. Also do not listen to people who will suggest you to buy most expensive/cool wood, because if you are doing it for the first time, you will most probably fail a few times before you can do something. When you see that you are ok, you can buy better materiel)
Lathe (it quickly rotates your piece, allowing you to create axis of rotation elements)
chisel (to make small holes inside)
file (to refine your piece and to add some details)
hammer (everyone needs hammer. You might need it to protect your pieces from other people)
varnish (when you finish your thing, you have to cover it look better or not to get a thorn)

Not all of the things are needed. Also do not be intimidated when you see that this things are so big and your pieces should be really small: there are small equivalents of all the tools.

Tools like lathe are expensive, but a lot of schools and may be some repair shops can have it. So it is a good idea to go and ask them for permission to use it (you also should be careful to read how to use it, because it can damage you).

So, you have the tools. First of all try to create bigger things. From my experience, the smaller the thing you want to do - the more careful/skilled you have to be. So try to create big pawn/rook in the beginning. Like 20-40 centimeters high. Not 2-4 cm. When you feel that you are good with big things, you can go smaller.

Having a lathe it will be pretty easy, because as you noticed - all the pieces (except of the knight) are symmetrical along the Z-axis. To carve the wood, you use lathe with chisel (it is hard for me to explain how it work: all you do is to move chisel to the spinning wood and it cuts away part of it). This way you can do everything except of a knight. For knight you have to use only chisel and it is really complicated (for people like me).

Mark the wood with pen/pencil/marker to know where you have to cut it and always compare the piece you do with the same one you already done (unless you want all your bishops to be a different diameter/size).

Than you refine your pieces with file, paint them and later varnish. Do not be disappointed if you will fail at the first time and do not try to use complicated designs in the beginning.

This is some old school techniques, for a new generation - take a look at 3d printer which can carve from wood.


Is this move valid in the rollerball chess variant?

No it is not legal. Just like in normal chess the king cannot move into check, even if it would 'win' the game.

http://en.wikipedia.org/wiki/Rollerball_%28chess_variant%29


Who won the FIDE Chess Clock Contract Bidding?

According to the FIDE website:

FIDE is pleased to announce that, in compliance with the published
Bidding Procedure, it completed the scoring of offers submitted for
the chess clock contract tender. The winners have been determined,
conditional on the manufacturers' signing binding contracts with FIDE.

So, FIDE have chosen a winner but the winners have not yet signed a binding contract.
Presumably the contract is still being negotiated.
Note this earlier link from August 2019 - https://old.fide.com/images/stories/NEWS_2019/FIDE_News/20190805-FIDE-Bidding_procedure-ChessClocks.pdf - defining the bidding process giving the following schedule:

9. Bidding Timeline
9.1 Bidding starts August 05, 2019.
9.2 End of inquiry period for bidders August 15, 2019.
9.3 FIDE publishes responses August 23, 2019.
9.4 Deadline for bidders to submit bids September 10, 2019.
9.5 FIDE announces the winner(s) September 23, 2019.
9.6 Deadline for winner(s) to sign a contract September 30, 2019.
9.7 Contract(s) shall come into force October 01, 2019.
9.8 Contract(s) effective through September 30, 2022.

According to the schedule published in August it was planned that contracts would have been signed and come into effect by now. Perhaps over optimistic on the part of FIDE.
Assuming that contracts have been signed and FIDE are keeping it secret or are too lazy to update their website would be very foolish. For a start the winners would almost certainly publish the fact widely.


Read the article "Evaluation of Material Imbalances" by GM Larry Kaufman:
The Evaluation of Material Imbalances.

He says about the bishop pair:

  The bishop pair has an average value of half a pawn (more when the
  opponent has no minor pieces to exchange for one of the bishops),
  enough to regard it as part of the material evaluation of the
  position, and enough to overwhelm most positional considerations.
  Moreover, this substantial bishop pair value holds up in all
  situations tested, regardless of what else is on the board. This large
  a bishop pair value is surprising because in the opening grandmasters
  will often give up the bishop pair to double the opponent's pawns or
  to gain a mild lead in development, factors which are generally not
  worth half a pawn [DH: Since at the very start of the game a tempo is
  worth roughly a third of a pawn - and more later! - it is worth losing
  a tempo to save the bishop pair, but if you can gain two tempo by
  giving up the bishop pair that may be worth it in the short run!]

Later, queen vs. two rooks:

  Although many authors talk about queen and pawn equaling two rooks,
  this is only close to true with no minor pieces on the board; with two
  or more minors each, the queen needs no pawns to equal the rooks. I
  recall a famous Portisch-Fischer game in which Portisch "won" two
  rooks for Fischer's queen right out of the opening, but Fischer soon
  won a weak pawn and went on to win rather easily, despite the nominal
  point equality. In fact Fischer's annotations severely criticized
  Portisch for making the trade; Fischer understood very well that with
  lots of material on the board, the queen is every bit as good as the
  rooks, so once he won a pawn he was effectively a full pawn ahead.

His basic tables of values is:

Pawn = 1
Bishop pair = +½
Rook =  5
Bishop = 3¼
Knight =  3¼
Queen =  9¾


Looking for instructive examples on how to defend against the Giuoco Piano or Giuoco Pianissimo (?) opening from Black's perspective

[fen ""]
[Event "Ding Liren - Giri"]
[Site "Wenzhou CHN"]
[Date "2017.08.09"]
[EventDate "2017.08.08"]
[Round "2"]
[Result "0-1"]
[White "Ding Liren"]
[Black "Anish Giri"]
[ECO "C50"]
[WhiteElo "2777"]
[BlackElo "2772"]
[PlyCount "90"]

1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. O-O Nf6 5. d3 O-O 6. h3 d6
7. c3 a6 8. a4 Ba7 9. Re1 h6 10. Nbd2 Be6 11. Bxe6 fxe6
12. Nf1 Nh5 13. Be3 a5 14. Bxa7 Rxa7 15. d4 Qf6 16. Re3 Nf4
17. h4 Qg6 18. g3 Raa8 19. dxe5 Nxe5 20. Nxe5 dxe5 21. f3 Rad8
22. Qc2 Nh5 23. Kh2 Rf6 24. Rd1 Rdf8 25. Rdd3 Qf7 26. Qd1 Rg6
27. Qe1 Qe7 28. Kh3 Rxg3+ 29. Nxg3 Nf4+ 30. Kh2 Qxh4+ 31. Kg1
Rf6 32. Rd8+ Kh7 33. Rd2 Rg6 34. Rg2 h5 35. Rh2 Rxg3+ 36. Kh1
Qg5 37. Qf1 h4 38. Re1 h3 39. Rd1 Qh5 40. Rd7 Qxf3+ 41. Qxf3
Rxf3 42. Rhd2 Kh6 43. Rd8 Kh5 44. Rh8+ Kg4 45. Rd1 Ne2 0-1

I think that the way Anish Giri plays the Italian as Black is very instructive.
It is also funny that White faced all the problems you mentioned having as Black in this game, and it shows how Black avoided the headaches you named.
Some ideas (I would not call them rules...) in the Italian...

I like to go ...a6 and ...Ba7 immediately and only then ...d6. It gets the bishop out of harms way so that we are more flexible in how we react to moves in the center, like d4 (because d4 does not hit the bishop anymore). And we can still retreat it with ...Be7 if that is how we want to parry Bg5 (matter of taste if you want to go for ...h6 and ...g5).
If White goes for the pin with Bg5 before Black has castled kingside, we go ...h6, ...g5 kicking the bishop and we may go for a kingside attack (even after we castle kingside outselves!). A useful maneuver to enable a pawnstorm is ...Nf6-h7 supporting the g5 pawn to play ...h6-h5 (once we are ready).
If White does not go for Bg5 early and plays slowly, a good plan is ...h6, ...Re8, ...Be6 and then ...Rxe6 after the bishops are swapped. The rook may stay on the 6th rank or reatreat back to the 8th.
If White goes for Be3, swapping there is usually okay if we have not played ...h6 yet, as ...h6 weakens squares around our king and we might get crushed after a sacrifice. But you never really have to take and while the rook may look bad on a7, it is not as far from the action as it may seem (see the game I posted).

You will still learn some common mistakes by White, like mistiming d4, leaving f2 vulnerable and others. Another thing to look up is how to deal with unsound sacrifices on f7 or g5 (after ...h6, ...g5 White very often plays Nxg5, but it mostly is not sound).
You also need to look for active play. If White's move seems very slow, or his forces do not look fully coordinated, you might have an opportunity to seize the initiative by striking in the center or on the kingside (mostly). If you look at the game I posted, it is not clear where the initiative of Black came from, but it crushed.


What should be my approach to checkmating efficiently?

There are a fair number of lines toward the end that make the fact that mate is forced a little hard to spot, but it's certainly doable. A couple example lines:

[FEN "r1bqk2r/ppp3Bp/2n5/8/1b2p3/1P2n1P1/P4PBP/RN1Q1KNR w kq - 0 0"]

1.Ke2 (1.fxe3 Qxd1+ 2.Kf2 Qe1#) Qxd1+ 2.Kxe3 Qd3+ 3.Kf4 Bd6+ 4.Kg5 Qd5+ 5.Kh6 Bg4 6.Bxh8 (6.Be5 Qxe5 7.Bxe4 Bf8#) Qh5+ 7.Kg7 Qg6#

As for learning to spot these mates yourself, part of the trick is recognizing that Black's pieces are hugely more active than White's, especially after the White Queen is gone. Black should look to control the White King's movement easily with the two Bishops and the Queen, and mate is surely inevitable. Finding the fastest mate is always nice, but at the end of the day, any line will do as long as it doesn't provide an opportunity for White to escape!

When calculating mating lines (or any combination), it's easiest to look for forcing moves: moves which leave the opponent with only a single move, if possible. This naturally limits the number of lines you have to calculate. Good candidates for forcing moves are checks, or other threats which must be dealt with immediately. For instance, I found the line above by simply evaluating, at each step, the move that gives White as few resulting choices as possible. Even 5...Bg4 is a forcing move, because it threatens immediate mate via ...Qh5.


Engine evaluating changing after making move suggested by engine

There's nothing surprising here. Chess engine is not perfect, as you make a move the evaluation will likely change:

The engine now sees something not seen before
The engine can now search deeper
The engine's hash table has relevant entries

This's just how we play chess. Our positional assessment change as we make moves. If that's not the case, there's no need to play the game - we shout out win/loss/draw without making a move.

Hint: If you're using your engine for your game, you'll need to make some moves to get better assessment. Kramnik did that for his win against Aronian:

  The computer doesn’t show it at the beginning, but then once you put it in he starts to like it a lot.

https://chess24.com/en/read/news/berlin-candidates-3-a-kramnik-immortal

Sorry, chess is a hard game.


What's the difference between SCID and SCID vs PC?

Shane's Chess Information Database (SCID) is a powerful Chess Toolkit, with which one can create huge databases, run chess engines, and play casual games against the computer or online with the Free Internet Chess Server. It was originally written by Shane Hudson , and has received strong contribution from Pascal Georges and others.

  Scid vs. PC began with bug-fixes for the computer-versus-player features of Scid (hence the name), but has evolved into a solid alternative with many new features and interfaces. The project is authored by Stevenaaus and numerous contributors.

So they are not the same. Scid vs. PC is a SCID variant.


One approach might be to go through all the moves of a high level game, and if the engine evaluation changes significantly, then save the position for human review.

In this case, "significantly" is probably half a pawn or more, although you could also require it to be one full pawn for easier tactics.

The rationale behind only looking at high level games is that the score will really only change significantly with a blunder.  High level games won't have obvious blunders (i.e. hanging a piece) so the blunders will possibly be a not-so-obvious tactic.

This won't be perfect, but it might get some positions worth looking at "by hand".

Just one more note - if you allow the chess engine to search to a sufficient depth (14-16 in most positions should be good) - then you won't have to worry about missing the start of the tactic.  The engines will be able to see most tactics, even if they are complicated.


1.Rh6

This puts Black in Zugzwang.

If 1...gxh6, 2.g7#

If Black moves the Bishop, 2.Rxh7#


At one point, I considered picking up the Glek variation, but I found the variation of 4... d5 to be far too problematic. Keep in mind, that the principle idea of the variation is to retain a knowledge advantage, but most importantly, retain plenty of opportunity for out-playing the opponent.

On this line, the d5 line puts direct challenge to the idea. Further, 5. exd5 Nxd5 6. Bg2 Nxc3 7. bxc3 From here, you should find a nice niche line. I recommend starting with 7... Bc5 or Bd6.

If you put any length of study into this line, you will face no issue what so ever in this variation. Most important though, especially for this line, is to master the principles of the strategy here instead of long series of lines.

Sample Game

Here is a nice execution by the French GM Laurent Fressinet where he managed to win against this opening (played against the eponym himself, the German GM Igor Glek)

[FEN ""]
[Site "Katernberg GER"]
[Round "13"]
[White "Glek, Igor"]
[Black "Fressinet, Laurent"]
[WhiteElo "2537"]
[BlackElo "2658"]
[Result "0-1"]
[ECO "C47"]
[Opening "Four Knights"]
[PlyCount "111"]

1. e4 e5 2. Nf3 Nc6 3. Nc3 Nf6 4. g3 d5 5. exd5 Nxd5 6. Bg2 Nxc3 7. bxc3
Bc5 8. O-O O-O 9. d3 Bg4 10. h3 Bh5 11. g4 Bg6 12. Ng5 h6 13. Ne4 Bb6 14.
Ba3 Re8 15. Kh2 Qd7 16. Rb1 Nd8 17. f4 exf4 18. Rxf4 Ne6 19. Rf1 c6 20. Kh1
Bxe4 21. Bxe4 Ng5 22. Bg2 Re6 23. Rf5 g6 24. Rf4 Rae8 25. Qf1 Bc7 26. Rf6
Bb8 27. Bc5 Re2 28. Bg1 Rxc2 29. Rf2 Rxc3 30. Re2 Rxe2 31. Qxe2 Rxd3 32. h4
Ne6 33. Rxb7 Qxb7 34. Qxd3 Qc7 35. Qb3 c5 36. Bd5 Qf4 37. a4 Be5 38. Qf3
Qxf3+ 39. Bxf3 Bd4 40. Bh2 c4 41. Kg2 c3 42. Bd1 Bf6 43. Bg1 Nd4 44. Bxd4
Bxd4 45. Kf3 Kg7 46. Kf4 Bf2 47. h5 Kf6 48. Kf3 Bb6 49. Ke4 Kg5 50. Kd3 Ba5
51. Be2 gxh5 52. gxh5 f5 53. Bd1 Kf4 54. Ke2 Kg3 55. Kf1 f4 56. Bc2 0-1


Herbert Simon touched on this question. He received the Turing Award in 1975 and the Nobel Prize in Economics in 1978. His primary research interest was decision-making and is best known for the theories of "bounded rationality" and "satisficing".

Satisficing is a decision-making strategy or cognitive heuristic that entails searching through the available alternatives until an acceptability threshold is met. Simon used satisficing to explain the behavior of decision makers under circumstances in which an optimal solution cannot be determined.

In his paper Theories of Bounded Rationality (1972), Simon used "the game of chess as a microcosm that mirrors interesting properties of decision-making situations in the real world." Here are some useful quotes.

  On the average, at any given position in a game of chess, there are
  about 30 legal moves-in round numbers, for a move and its replies, an
  average of about 10^3 continuations. Forty moves would be a not
  unreasonable estimate of the average length of a game. Then there
  would be perhaps 10^120 possible games of chess. Obviously the exact
  number does not matter: a number like 10^40 would be less
  spectacular, but quite large enough to support the conclusions of the
  present argument.

  Chess players do not consider all possible strategies and pick the
  best, but generate and examine a rather small number, making a choice
  as soon as they discover one that they regard as satisfactory.

The limits of rationality in chess.

  (...) three limits on perfect rationality were listed: uncertainty
  about the consequences that would follow from each alternative,
  incomplete information about the set of alternatives, and complexity
  preventing the necessary computations from being carried out. Chess
  illustrates how, in real world problem-solving situations, these three
  categories tend to merge.

Satisficing and optimizing.

  The terms satisficing and optimizing (...) are labels for two broad
  approaches to rational behavior in situations where complexity and
  uncertainty make global rationality impossible. In these situations,
  optimization becomes approximate optimization - the description of the
  real-world situation is radically simplified until reduced to a degree
  of complication that the decision maker can handle. Satisficing
  approaches seek this simplification in a somewhat different direction,
  retaining more of the detail of the real-world situation, but settling
  for a satisfactory, rather than an approximate-best, decision. One
  cannot predict in general which approach will lead to the better
  decisions as measured by their real-world consequences. In chess at
  least, good players have clearly found satisficing more useful than
  approximating-and optimizing


How to make an AI chess engine which can play like a human of similar rating?

You can take a look at the Maia Chess project. What they've done is that they've built a customized version of Leela Chess wherein instead of the policy value looking for the best move, it looks for the most likely human move. The github has 9 weight files for lc0 from 1100 to 1900 elo.
It claims to better predict the moves of players compared to Stockfish and Leela Chess. You can also play these bots at Lichess.


Touching an opponent's piece with one of your pieces

According to the FIDE Laws of Chess, this all depends on whether it was intentional or not (of course, here I'm assuming you play under a Federation that follows the FIDE rules, or very similar ones). Article 4: The act of moving the pieces stands as follows (article 4.2 is the adjusting rule):

  4.3
  Except as provided in Article 4.2, if the player having the move deliberately touches on the chessboard:

  a.
  one or more of his own pieces, he must move the first piece touched which can be moved

  b.
  one or more of his opponent’s pieces, he must capture the first piece touched which can be captured

  c.
  one piece of each colour, he must capture the opponent’s piece with his piece or, if this is illegal, move or capture the first piece touched which can be moved or captured. If it is unclear, whether the player’s own piece or his opponent’s was touched first, the player’s own piece shall be considered to have been touched before his opponent’s.

If the move is not intentional (you drop your piece over an opponent's), then you don't have to take it. If it is intentional, it is certainly true that it is not specified if touching is with the fingers or the pieces, but as many players use both, I would say that both apply as touching.


My short answer: no, computers are not destroying chess. And now here comes a really long version ...

Your first question:

  It is true the engines have level up the game, but can we also conclude that engines at a certain level are destroying the human cognitive process of figuring out moves by themselves over the board (mainly at opening phase)?

As indicated above, in a word, I'd say no. In more words, I don't think there's anything particular to engines about the phenomenon you describe, and the "problem" of preparation, to whatever degree it exists, is really just about the single, well-analyzed starting position of chess. Chess960 (as alluded to in Fischer's earlier answer) tries to address that latter concern, as did things like Capablanca Chess well before that. When Capablanca thought that chess theory was all played out already in the 1920s, it certainly wasn't because of the chess engines of his day (and he also happened to be quite premature in his assessment).

Yes, engines raise the quality of players' home preparation these days and can do a lot of heavy lifting, but still the engines are just tools which strong players use to aid their creative opening endeavors. Consider this: even if you were to have as fantastic a chess memory as, say, Kramnik, so that you could efficiently memorize a ton of engine-aided preparation, if you don't also have Kramnik's all-around understanding of the game and what to aim for out of the opening, the preparation he has memorized will far outshine yours, not necessarily in the quality of the individual moves, but certainly as regards the body of lines he has chosen to learn. (And of course, there will still basically always come a point in the game where the preparation is left, and Kramnik will certainly start crushing you then.) Some players are stronger than others, and that sort of strength still applies to engine-aided preparation.

Again, there is nothing special about engines here. The same was true of preparation in eras where it was aided only by books and periodicals; then too games were sometimes won simply from superior opening preparation. Here is a game from 1935 in which Botvinnik does just that, and which GM Kavalek references in a recent article on the sixth world champion:

[fen ""]
[White "Mikhail Botvinnik"]
[Black "Rudolf Spielmann"]
[Event "Moscow 1935"]

1.c4 c6 2.e4 d5 3.exd5 cxd5 4.d4 Nf6 5.Nc3 Nc6 6.Bg5 Qb6?! 7.cxd5! Qxb2? 8.Rc1! Nb4 9.Na4 Qxa2 10.Bc4 Bg4 11.Nf3 Bxf3 12.gxf3 1-0

As Kavalek notes, Spielmann had played the white side of this line up through move 6 the previous year, though in that game he played the weaker response 7.c5?!:

  [The aggressive move 6...Qb6?!] was recommended by the Czech master Karel Opocensky in his chess column in Narodni politika and it was used for the first time by Josef Rejfir against Spielmann in Maribor 1934. 'Surprising and good,' wrote Rejfir in Ceskoslovensky Sach 8-9/1934 about Opocensky's invention. The Wiener Schachzeitung called it the Prague variation.

So Spielmann was certainly familiar with this line when he chose to go into with the black pieces. But Botvinnik was also familiar with the earlier game, and he managed to analyze a bit deeper than had been done before, which netted him a win out of the opening. That sort of thing happened before engines, and sometimes happens with them today. Still, in the preparation itself, as well as playing the games once out of preparation of course, the skill and creativity that chess has always demanded is squarely on display.

Given what I've written above, my response to your other question is probably pretty predictable.

  How can someone play the game in a way that he can avoid computer home preparation?

Just try and end up in a line that your opponent hasn't analyzed. But again, I would stress that there is nothing particular to computer home preparation here; it's the same problem it has always been. If I'm Rudolf Spielmann, and I recently got burned by Botvinnik's home preparation (without engines of course), then if I want to avoid the same fate next time we play I need to try and steer the game to lines where Botvinnik won't have had the chance to out-analyze me ahead of time. Maybe I'll be successful, maybe I won't, but the challenge was the same in the era of books as it still is in the era of engines.