Rating rise: luck or actual increase in playing strength?

Is there a way to distinguish whether a rating rise/drop can be
  explained by random factors, e.g. "(bad) luck", being "in/out form",
  etc..., or an actual increase/decrease in playing strength?

No, would be my answer, at least there is no easy way to distinguish.

The problem is that there are very many factors affecting ratings.

For instance, about 5 years ago FIDE changed the system. I'm not sure if it was lowering the minimum rating, changing the k factors or a combination of these but the net effect was a rating deflation. Talking to a range of players it seems that there was an influx of very underrated juniors into the system. One disgruntled player complained of losing or drawing to juniors who were, in his opinion, as much as 400 points underrated.

Over the following 2 years I noticed a 150 point drop in my rating and anecdotal evidence is that many other older players who have had stable ratings for many years noticed the same kind of drop. Over the last year these same players have reported that their ratings are rising back towards their old averages and attribute this to the system regarding rating of junior players (perhaps with their higher k value) as "settling down". I have to admit I haven't noticed this effect yet ;-), but then I played very few games in the last year. I hope this means I have something to look forward to if I go back to playing a lot more games!

You can also have anomalies due to the average strength of the players you play against. If you play a lot of players who are much, much weaker or much, much stronger than you then this can also distort your rating due to the way they are calculated.

Finally, I would just add that FIDE only attempts to measure my rating "sitting down". My rating "standing up" is at least 300 points higher ;-).


How do I play the Colle System as white?

It would be easier to answer would you show us some of your games where you tried the f3-plan.

5.Ne5 or 5.0-0 aiming for a quick f2-f3 indeed make sense. However, I would argue that the most logical answer is to quit your Colle schemes (after all, Black has a strong grip on e4...) and switch to 5.c4 (or 5.0-0 first, followed by 6.c4)

After 4...Ne4 Black has played twice the same piece and reduced his control of d5. The early development of Bc8 has also left b7 unprotected, which may become a target to a later attack by Qb3.

After the approximative line 5.c4 e6 6.Nc3 (6.Qb3!?, 6.Qc2!?, 6.0-0) c6 7.Qc2 Black cannot maintain his e4-outpost:

7...Bb4 8.0-0

7...Nxc3 8.Bxf5 exf5 9.bxc3 and Black center will collapse to a later cxd5 and c3-c4.

7...Nd6 might be best but Black has lost some time. You can try to exploit this by giving a pawn with 8.Bxf5 Nxf5 9.0-0 followed by e3-e4, or play more conservatively with 8.b3. White must be slightly better.


A few ideas:

Michael Goeller's Pawn Battle  which introduces a checkers-like game (that still follows the rules of chess) that wonderfully folds in key pawn concepts like break moves, sacrificing to clear a line and even zugzwang. This exercise also helps kids learn to appreciate calculating outcomes beyond just "Hope Chess"-ing it out.
Some of the handouts at ProfessorChess.com contain exercises and drills that are fun and instructive.
Basic won endgames :  These can be fun, simple positions which very direct goals and often gets done within minutes as they start to figure out how to solve them.  Start up with KQ vs K setups and move up the ladder of complexity to KR vs K and even KP vs K.  These fundamental skills stay with them as they progress with their chess.

An added funsy way of doing the above is to use 2 x 8-sided dice to randomly assign squares for pieces in the starting position (e.g. K goes here, other K goes there, the Queen goes here. Play to win!). You could go all out and even create a roulette wheel of different drills to perform!


How to prepare for a handicap game (queen odds) / strategy?

Years ago my club in England ran a handicap tournament in the summer, which I organised and also played in. Had you and your friend been members, I think you would have played at Queen odds, or maybe Rook plus time handicap. In our tournaments the odds-givers did surprisingly well. Here is some advice based on that, although your own list is already pretty good.

Dont go for a briliancy. If it happens it happens, but dont set your sights on it.
Done even go for active development. Pieces out in the middle get exchanged off. Keep things closed, but retain the option to open them up.
Dont set up direct threats unless they are well hidden or unstoppable. You may just force him to make good moves.
Set up an unfamiliar situation in the opening. I had good results with 1. b3. English could be good also. And it still is an English without your Queen. You just wont be playing book lines.
Keep central control and identify important squares.
Stay mobile and flexible. Steadily improve your position. Wait for the opponent to make mistakes. He will. You are correct that he will not make good plans. He will be reluctant to sacrifice.

Playing like this you will probably win some material about once in every ten moves. Wait until material is fairly equal before you try for a mating attack.


Pawn promotion to queen of the other color

Promoting to a piece of the opposite color is an illegal move. Because of the touch move rule, Black must make a different legal move with that pawn, such as promoting to a Black queen. As a penalty for making an illegal move, two minutes are added to White's clock.


Well that depends, if your talking about a game as in chess then no. If your opponent is in zugzwang he may deliberately allow his time to expire so that his opponent may move and likewise the opponent would let their time expire to put his opponent back in zugzwang. Basically the game would go on and on... With no one making any moves.
However if you are talking about another computer based game, you must make sure that zugzwang does not exist, then this system of time control would work.( zugzwang is when any move you make only worsens your position.


Transposition Tables Bug, implementation produces different results

I am not sure I understand your exact code but my guess here is that you return a transposition table result, no matter the depth of the entry. So if you encounter a position and calculate it one ply deep, store it in the transposition table, and then the next iteration you want to search two plies deep but instead retrieve a one ply deep evaluation from the transposition table. The way around this is to store the depth in the transposition table entry and then only accept an entry if its depth is greater or equal than the required depth.
Another issue to take note of is that with an alpha beta search, for most nodes you won't know the exact evaluation, only an upper or lower bound. So if you store something in the transposition table you also have to remember whether the evaluation is an upper or lower bound, and then when retrieving have logic accordingly.


Tactics play the most important part of winning blitz games. The tactical player has a better chance of winning a blitz game rather than a quiet, positional player (it is the other way round for classical chess). Next is intuition. To succeed as a blitz player, you must be able to figure out the next move without going into deep calculations (i.e. 'feel' the next move). For example, here is a game from your Chess.com account I analysed with a computer:

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
[Event "Live Chess"]
[Site "Chess.com"]
[Date "2018.12.09"]
[Round "-"]
[White "quizhead (1238)"]
[Black "redhatkillers (1208)"]
[Result "0-1"]
[WhiteElo "?"]
[BlackElo "?"]
[Variant "Standard"]
[TimeControl "-"]
[ECO "A02"]
[Opening "Bird Opening"]

1. f4 g6 2. Nf3 Bg7 3. e4 e6 4. Be2 a6 5. d4 b5 6. O-O Ne7 7. c3 f5 8. e5 Bb7 9. Be3 Bh6 10. Nbd2 Nd5 11. Bf2 Bxf4 12. Bh4 Qc8 13. Bf2 Be3 14. Kh1 Bxf2 15. Rxf2 Qd8 16. Qc2 g5 17. Raf1 g4 18. Ne1 Ne3 19. Qd3 Nxf1 20. Bxf1 Qh4 21. Qe3 Nc6 22. Nd3 Na5 23. Nf4 Rg8 24. b4 Nc4 25. Nxc4 bxc4 26. Qg3 Qxg3 27. hxg3 h6 28. Bxc4 c6 29. Bb3 a5 30. a3 axb4 31. axb4 Ba6 32. c4 Ke7 33. Rf1 Rg5 34. Rd1 Rh8 35. d5 h5 36. dxc6 dxc6 37. Nd3 h4 38. Nc5 hxg3+ 39. Kg1 Bc8 40. b5 cxb5 41. cxb5 Rgh5 { Black wins. } 0-1

10. Nbd2 is a normal move in an opening, but unfortunately not here. Your opponent has the massive d5 square for their knight. You should have paid attention to Nd5. It forks the bishop and the pawn, and you are forced to give up the pawn. 10. g3 would've saved the pawn, though that knight is still annoying.

17. Raf1 allows a fork too. From the d5 square the knight is a serious threat. Usually when a knight is about to enter your territory, you must give it adequate attention.

25. Nxc4 looks like it wins a pawm worsens your position. Your opponent didn't notice that 25... g3 wins your rook, and fortunately you had a chance to correct that by playing Qg3.

These are just some remarks. There is still much to learn, by playing more and more games and highlighting the positions where you blunder such tactics. It happens to us all. As it is said, the player to make the next to last mistake usually wins. We all do fall for such tactics, but one needs to minimize this to have a good chance at blitz.


From which top class game is the endgame motive?

You are probably thinking of the game Karpov - Kasparov  form  round 9 in their first World Championship Match in 1984-85. This match was later called off after 48 games before a winner was declared.

The situation you describe appeared after black's 46th move in this game.

[FEN ""]
[Event "World Championship Match"]
[Site "Moscow"]
[Date "1984.10.05"]
[Round "9"]
[Result "1-0"]
[White "Anatoly Karpov"]
[Black "Garry Kasparov"]
[Startply "92"]

1.d4 d5 2.c4 e6 3.Nf3 c5 4.cxd5 exd5 5.g3 Nf6 6.Bg2 Be7 7.O-O
O-O 8.Nc3 Nc6 9.Bg5 cxd4 10.Nxd4 h6 11.Be3 Re8 12.Qb3 Na5
13.Qc2 Bg4 14.Nf5 Rc8 15.Bd4 Bc5 16.Bxc5 Rxc5 17.Ne3 Be6
18.Rad1 Qc8 19.Qa4 Rd8 20.Rd3 a6 21.Rfd1 Nc4 22.Nxc4 Rxc4
23.Qa5 Rc5 24.Qb6 Rd7 25.Rd4 Qc7 26.Qxc7 Rdxc7 27.h3 h5 28.a3
g6 29.e3 Kg7 30.Kh2 Rc4 31.Bf3 b5 32.Kg2 R7c5 33.Rxc4 Rxc4
34.Rd4 Kf8 35.Be2 Rxd4 36.exd4 Ke7 37.Na2 Bc8 38.Nb4 Kd6 39.f3
Ng8 40.h4 Nh6 41.Kf2 Nf5 42.Nc2 f6 43.Bd3 g5 44.Bxf5 Bxf5
45.Ne3 Bb1 46.b4 gxh4 47.Ng2 hxg3 48.Kxg3 Ke6 49.Nf4+ Kf5
50.Nxh5 Ke6 51.Nf4+ Kd6 52.Kg4 Bc2 53.Kh5 Bd1 54.Kg6 Ke7
55.Nxd5+ Ke6 56.Nc7+ Kd7 57.Nxa6 Bxf3 58.Kxf6 Kd6 59.Kf5 Kd5
60.Kf4 Bh1 61.Ke3 Kc4 62.Nc5 Bc6 63.Nd3 Bg2 64.Ne5+ Kc3 65.Ng6
Kc4 66.Ne7 Bb7 67.Nf5 Bg2 68.Nd6+ Kb3 69.Nxb5 Ka4 70.Nd6 1-0


No.

The reason for a no, lies in your question. If you want "liberal free license" you are asking for free software and “free software” is a matter of liberty, not price, since you specifically said "(no GPL)" then your request is contradictory.

However, if you do want “free” (as in “free speech,” not as in “free beer”) opening database, there are some options.

You can build small (1 MB), medium (25 MB), or large (58 MB) opening books for Crafty, that will give you enough material for a couple of years, maybe even more.


The Black king is in check from both the White rook and queen, so it's impossible that either piece moved to give a check, it must have been a discovered check on the last move, which makes the White pawn on g6 the likely piece that was last moved.
White's last move must have been hxg6 en-passant. Which makes Black's previous move g7-g5 to block the check from the White queen.


I think the following will happen at chess.com:

If KNN runs out of time, KR wins.
If KR runs out of time, it is a draw.

If chess.com abides by the FIDE Laws of Chess then this is false.
If the side with K+R runs out of time then they lose. K+R vs K+N will also lose. This is the relevant article:

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.

Here is the relevant helpmate position for K+N vs K+R. No second knight is needed.
[FEn "kr6/2N5/K7/8/8/8/8/8 w - - 0 1"]

Isn't this unfair?

If what you say is correct regarding chess.com's interpretation of the rules then, of course, it is grossly unfair. They would be much fairer if they abided by the FIDE Laws of Chess.


Question: What are black's possible plans in the exchange variation of
  the Queen's Gambit?

I think the positions could be classified into two main types depending upon where White develops the g1 knight - f3 or e2.

A) Black's ideas when White develops Knight on f3

1) Knight mavouvere - d7-f8-e6-g7 followed by Bf5!

A very interesting idea was introduced in the game Reshevsky vs Stahlberg, 1937. Instead of "automatically" castling, Black first mavouvers the knight to e6, thereby saving a tempo and prepares to play g6 followed by Ng7 and Bf5! In his DVD on the Queens Gambit, Garry Kasparov considers this to be Black's main idea of solving the problem of the bishop on c8 and also exchanging White's strong bishop on d3.

  [Event "Knight manouvere d7-f8-e6-g7 followed by Bf5!"]
  [Date "1937"]
  [White "Reshevsky"]
  [Black "Stahlberg"]
  [Result "1/2-1/2"]
  [FEN ""]

    1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Be7 5. Bg5 Nbd7 6. cxd5 exd5 7. e3 c6 8.
    Qc2 Nf8 9. Bd3 Ne6 10. Bh4 g6 11. O-O-O O-O 12. Kb1 Ng7 13. h3 Bf5 14. Bxf6
    Bxf6 15. g4 Bxd3 16. Qxd3 Ne6 17. h4 c5 18. dxc5 Bxc3 19. Qxc3 Rc8 20. e4 Rxc5
    21. Qa3 Qd6 22. exd5 Rd8 23. Qxa7 Rxd5 24. Rxd5 Qxd5 25. Qe3 h5 26. Re1 hxg4
    27. Ne5 Ng7 28. Qe4 Qxe4+ 29. Rxe4 f5 30. Rc4 Kh7 31. Kc2 Re8 32. Nd3 Ne6 33.
    a4 Kh6 34. Rb4 Re7 35. Rb6 f4 36. Rb4 g5 37. hxg5+ Kxg5 38. Rb5+ Kh4 39. Re5
    Nd4+ 40. Kc3 Rxe5 41. Nxe5 Ne6 42. Nd3 f3 43. b4 g3 44. fxg3+ Kxg3 45. a5 Nf4
    46. Nc5 Kg2 47. Ne4 Nd5+ 48. Kb3 Nc7 49. Kc4 Ne6 50. b5 Ng5 51. Nd2 f2 52. a6
    Ne4 53. axb7 Nxd2+ 54. Kc3 f1=Q 55. b8=Q Qc1+ 56. Kd3 1/2-1/2

2) Traditional plan of equalizing with Ne4.

This is a very solid idea for Black to equalize. It leads to an exchange of pieces and stops White's ideas of pushing e4, thereby neutralizing White's positional advantage.

A sample line is

  [Event "Traditional plan of equalizing with Ne4"]
  [FEN ""]

  1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. cxd5 exd5 5. Bg5 Be7 6. e3 c6 7. Qc2 O-O 8. Bd3
  Nbd7 9. Nf3 Re8 10. O-O Nf8 11. h3 Ne4

Note that this is a general idea and could be played in many different move orders. Here are some sample Grandmaster games where Black successfully used this idea to equalize and then even went on to win the game.

Pavel Eljanov vs Yuriy Kryvoruchko, 2013 0-1

Athanasios Mastrovasilis vs Mikhail Gurevich, 2007 0-1

3) Prevent minority attack with a timely b5 and invite White to overextend.

If Black doesn't employ the earlier ideas, then Black has to passively defend the position a bit longer. However, this often has the added psychological ploy of inviting White to overextend in his/her efforts to win from their "better" position. I found this Grandmaster game where Black manages to prevent the minority attack and White ends up overextending and actually losing the game.

Pavel Maletin vs Vladimir Malakhov, 2008 0-1

    [Event " Prevent minority attack with a timely b5 and invite White to overextend"]
    [Date "2008"]
    [White "Maletin"]
    [Black "Malakhov"]
    [Result "0-1"]
    [FEN ""]

    1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 e6 5. Bg5 Nbd7 6. cxd5 exd5 7. e3 Be7 8.
    Bd3 O-O 9. Qc2 Re8 10. h3 Nf8 11. Bf4 Be6 12. O-O Bd6 13. Bxd6 Qxd6 14. Rab1 a5
    15. a3 N6d7 16. Rfc1 Rec8 17. Ne2 b6 18. b4 axb4 19. axb4 b5 20. Nf4 h6 21. Qd1
    Nb6 22. Ne5 Nc4 23. Qh5 Rc7 24. Bc2 Ra2 25. Ned3 Rca7 26. Bb3 R2a3 27. Rd1 Bc8
    28. Nc5 g5 29. Nfd3 Bf5 30. Qf3 Bg6 31. Rbc1 Be4 32. Qe2 Bxd3 33. Rxd3 Ne6 34.
    Bxc4 bxc4 35. Rxa3 Rxa3 36. Qb2 Ra7 37. b5 cxb5 38. Qxb5 Kg7 39. Rb1 Rc7 40.
    Qb2 Qc6 41. Rc1 Nxc5 42. dxc5+ f6 43. Ra1 Qxc5 44. Qb8 Rf7 45. Ra8 Qf8 46.
    Qxf8+ Rxf8 47. Ra5 Rd8 48. g4 Kf7 49. Kf1 Ke6 50. Ke2 h5 51. gxh5 Rh8 52. e4
    dxe4 53. Rc5 Rxh5 54. Rxc4 Ke5 55. Rc5+ Kd6 56. Rc3 Rh8 57. Ra3 Ke5 58. f3 f5
    59. fxe4 fxe4 60. Kf2 Kf4 61. Kg2 Rb8 62. Ra2 Rb3 63. Ra8 Rb2+ 64. Kf1 Kf3 65.
    Rf8+ Kg3 66. Rf5 Kh4 67. Re5 Rb3 68. Rxe4+ Kxh3 69. Re1 Kh2 70. Re2+ Kh1 71.
    Re4 Rf3+ 72. Ke2 Rf5 0-1

B) Black's ideas when White develops Knight on e2.

This is actually a more critical line than the Nf3 variation. In his aforementioned DVD, Kasparov claims that the results with Ne2 are in favor of White and looking at the games at the highest level, I have to agree with him.

Searching through a database, I found that the highest rated player to play this setup with Black was Ivanchuk against Carlsen in 2009. In that game Ivanchuk had to resort to passive defense and Carlsen missed a move which could have given him a decisive advantage.

Carlsen vs Ivanchuk 2009 1/2-1/2

Yusopov beat Portisch in this line way back in 1986 by first defending passively and then embarking on a kingside attack, although this cannot be suggested as a "general idea", so use this with caution.

Portisch vs Yusopov, 1986 0-1

  [White "Portisch"]
  [Black "Yusopov"]
  [FEN ""]
  [Event "Passive queenside defense followed by kingside attack"]
  [Result "0-1"]
  [Date "1986"]

   1. c4 e6 2. Nc3 d5 3. d4 Nf6 4. cxd5 exd5 5. Bg5 Be7 6. e3 Nbd7 7. Bd3 O-O
   8. Nge2 Re8 9. O-O c6 10. Qc2 Nf8 11. Rab1 Be6 12. b4 a6 13. Na4 N6d7 14. Bxe7 Qxe7
   15. Nc5 Nxc5 16. bxc5 Rad8 17. Rb2 g6 18. Rfb1 Bc8 19. Nc1 Rd7 20. Nb3 Ne6
   21. Na5 Nd8 22. Qd1 h5 23. Qf3 Kg7 24. h3 h4 25. Qf4 Rc7 26. Kf1 Rh8 27. Rb3 g5
   28. Qh2 f6 29. R1b2 Nf7 30. Ke1 Re8 31. Kd1 f5 32. Re2 Qd8 33. Rb6 f4 34. exf4 Rxe2
   35. Kxe2 Qf6 36. Rb4 gxf4 37. Kd2 Re7 38. Qh1 f3 39. Kc3 Ng5 40. gxf3 Qf4
   41. Rb1 Nxf3 42. Nb3 Kf8 43. Rd1 Ng5 44. Nd2 Rf7 45. f3 Nxh3 46. Re1 Ng5 47. Re2 Re7
   48. Rxe7 Kxe7 49. Qe1 Be6 50. Qb1 h3 51. Qxb7 Bd7 52. Qa8 h2 53. Qh8 Nh3

1) New Idea - knight maneuver d7-f8-e6 followed by bishop to b7.

Nubairshah Shaikh vs Arvindh Chithambaram 2013 0-1

I came across a recent interesting game by India's rising star Arvindh Chithambaran. The idea, as I understand it, is to maneuver the knight to e6, develop the bishop on b7 and then invite White to trade the dark squared bishops. Black can also play f5 considering the fact that the knight on e2 cannot really get to the outpost created on e5.

   [Event "knight maneuver d7-f8-e6 followed by bishop to b7"]
   [Date "2013"]
   [White "Shaikh"]
   [Black "Chithambaram"]
   [Result "0-1"]
   [FEN ""]

    1. d4 Nf6 2. c4 e6 3. Nc3 d5 4. cxd5 exd5 5. Bg5 Be7 6. e3 c6 7. Bd3 Nbd7 8.
    Qc2 Nf8 9. Nge2 Ne6 10. Bh4 g6 11. O-O O-O 12. f3 b6 13. Rad1 Bb7 14. Kh1 Rc8
    15. a3 Nh5 16. Bf2 f5 17. b4 Bd6 18. f4 b5 19. Ng1 a5 20. Rb1 Nf6 21. Bh4 Ra8
    22. Nf3 Qe7 23. Bxf6 Qxf6 24. Ne5 Qe7 25. Qb2 Ra7 26. Rfc1 Rfa8 27. h3 Ng7 28.
    Rc2 axb4 29. axb4 Ra6 30. Qc1 Ne8 31. Ne2 Ra3 32. Qd2 R8a6 33. Kh2 Nf6 34. Nc1
    R3a4 35. Rcb2 Nd7 36. Nxd7 Qxd7 37. Bc2 Ra3 38. Nd3 Qe7 39. Bb3 Kg7 40. Nc5
    Bxc5 41. dxc5 Ra8 42. Qd4+ Qf6 43. Rd2 Re8 44. Kg1 Re4 45. Qxf6+ Kxf6 46. Bc2
    Rexe3 47. Kf2 Bc8 48. Bd1 Re4 49. Bf3 Rxf4 50. Re2 Be6 51. Rbe1 Re4 52. Bxe4
    dxe4 53. Rb2 Bd5 54. Rbb1 Ra4 55. h4 f4 56. g3 Ra2+ 57. Re2 fxg3+ 58. Ke3 Ra3+
    59. Kd2 Ke5 60. Re3 Ra2+ 61. Kc3 Kf4 62. Ree1 e3 63. Ra1 Rxa1 64. Rxa1 g2 65.
    Re1 Kf3 66. Kd4 Kf2 67. Ra1 e2 0-1

2) Preventing the Ne2 line altogether by playing an intermediate move 3...Be7!?

    [Event "Black plays 3...Be7!? and White is unable to get both Bg5 and Ne2"]
    [FEN ""]

    1. d4 d5 2. c4 e6 3. Nc3 Be7!?

3...Be7 puts White in a dilemma because White cannot get in both Bg5 and Ne2. White has to try Bf4, but then Black's kingside is not pressured as much as after Bg5. In some lines, Black can once again follow the same plan of knight maneuver to e6 followed by g6 and Bf5.

     [Event "Sample lines after 3...Be7"]
     [FEN ""]

     1. d4 d5 2. c4 e6 3. Nc3 Be7 4. cxd5 (4. Bf4 Nf6 5. Nf3 O-O 6. e3 Nbd7 7. c5 c6
     8. Bd3 b6 9. b4 a5 10. a3 Ba6 11. O-O Qc8 12. h3 Qb7) (4. Nf3 Nf6 5. Bg5 c6 6.
     e3 Nbd7) 4... exd5 5. Bf4 Nf6 6. Nf3 O-O 7. e3 c6 8. Bd3 Nbd7 9. Qc2 Re8 10. h3
     Nf8 11. O-O Ne6 12. Bh2 g6

P.S. This is definitely the longest I have spent answering a single question on chess.stackexchange.com!


Analysis of a position-Why is my move so bad?

The reasons for not playing 20...c5 are mainly tactical. 20...g5 21. Qg4 h5 22. Qxh5 Bxd4 23. Bxd4 Qxd4 24. Qxg5+ Qg7 wins a piece for two pawns. Since you are already down three pawns for nothing, it won't do to just sit around and wait.

[fen "1n1qr1k1/pr3ppp/2p2b2/8/2PN1Q2/2BP2P1/PP2PP1P/3R1RK1 b - - 0 20"]

1... g5 2. Qg4 h5 3. Qxh5 Bxd4 4. Bxd4 Qxd4 5. Qxg5+ Qg7


Why does Stockfish undervalue pawns when compared to the classical "a piece is worth three pawns" approach?

I am not an expert on stockfish source code, but my understanding is the following.

Humans:

It is true, that the  1 piece equals 3 pawns approach is pretty accurate, surprisingly so. However as you are probably aware, when evaluating a position, we consider many other aspects as well, such as piece activity, space, king safety, etc. The difference however is that we don't assign actual numerical values to these other factors.

Stockfish (or similar engines):

Unlike humans, engines assign numerical values to all factors. The numbers you mention are just a small part of the evaluation function.

Check out the middlegame evaluation function for stockfish. On that page you can also modify the board to see the evaluation and you can visit the specific functions such as `piece_value_mg' which is concerned with these numbers.

As you can see, just the piece values of all pieces amount to 9326. However there are many other functions which add to the evaluation. Most importantly, not all of these extra functions treat pawns and pieces equally.

For instance:

`Psqt mg', gives values to pawns only, depending on their position on the board. As you would expect,  pawns in the center are more valuable (pawn on e4 instead of e2 is +24 points)
another pawns only function: `Pawns mg' gives points depending on the pawn structure (isolated, doubled, connected pawns, etc) also here you can gain several tenth of points for the pawns (but not for the pieces).

To be fair, there are also functions that only deal with pieces such as `Pieces mg'. However note that they can also give a penalty (negative value) to the total evaluation. In fact for the starting position you have -63 from that function.

In summary...

Stockfish has a much more fine grained evaluation function than we humans do. The pure piece value from stockfish cannot really be compared with the human piece value.

In stockfish pieces and pawns can gain points in other ways beyond the values you mention. Furthermore, stockfish does not consider the piece on its own, but also how it relates to other pieces, e.g. whether there are doubled pawns, an outpost, etc.

If you check out the code, these other factors are each in the range of several ten points, so if you take them all together you might very well gain the 100 points necessary for the pawn to be 1/3 of a piece.

Mathematically you could also consider it as a kind of approximation or averaging in which you assign a single number (human piece value) for the very complex system that stockfish uses. There is no reason that the average value (human piece value) has any relation to one of the parameters (ValueMG) in the stockfish universe.

I really recommend to see for yourself at the link how much more complete the stockfish evaluation is.


Meaning and origin of 'theory' in 'opening theory'

You are right in your assessment of the usage.

Opening theory refers to particular variations; but also to typical plans specific to the respective openings.

Opening principles (develop pieces, occupy the center...) are of a more general nature applying to all (or most) openings and is closer to what one would consider a "theory".

I don't have a good answer to your question, but in recent years at least there has been a trend away from playing based on opening principles towards  concrete play. So perhaps at one point in time, "opening theory" was a lot more based on principles and less concrete lines!?


Chess problem by A. G. Kopnin - Russian notation explanation needed

What move is the "1…ed" for example?

"ed" indicates that an e pawn takes a d pawn.

Maybe I would not understand it even if it was in English notation

It is actually in algebraic notation. If you follow the link you will find that it even tells you what the Russian abbreviations are for the pieces!
From there it is easy to work out that this is what it means:
[Title "Alexey Grigorievich Kopnin - mate in two - 1948"]
[FEN "nR1rB3/2PPPN2/bbk1N3/1p2p3/1p2P1nq/1K1Pp3/7B/8 w - - 0 1"]

1. d4 {threat d5#} exd4 (1...Nxc7 2. Nexd8#) (1...Bxd4 2. cxd8=N#) (1...Nf6 2. exd8=N#) (1...Rxb8 2. d8=N#) (1...Rxe8 2. dxe8=B#) 2. Nfxd8#

Note that "mate in 2" means that white mates in 2 moves exactly against any defence. Hence listing all the possible black replies to the first move.


It does not have any special name. I have been playing for 40 years, and I have never seen it given any specific name.

Here is a very good list of named mates, and as you can see, your position is not among them.


How can I improve and get to know the game?

Chess is a game of strategy and tactics. Each player commands an army of 16 chessmen --- pawns and other pieces (the king, queen, bishops, knights, and rooks).

A well-played chess game has three stages. In the opening, the players bring out their forces in preparation for combat. The middlegame begins as the players maneuver for position and carry out attacks and counterattacks. The final stage is the endgame when, with fewer pawns and pieces left on the board, it is safer for the kings to come out and join the final battle.

As play proceeds, each player will capture some of the opponent's men; often, the capturing pieces are immediately recaptured. As long as the piece a player gives up is generally equal to the piece he gets in return, we say the players are exchanging. If you unintentionally place a piece where it can be captured without getting a piece of equal value in return, we say that you put that piece en prise. (This is a French term that literally means "in take.") Sometimes a player may place a piece en prise in order to trick an opponent. If the opponent captures the offered man, it may leave him open to attack.

You're Ready to Go!

It's time for you to take a look at these ten tips to help you learn some simple ways to win more games:

1 Look at your opponent's move.
2 Make the best possible move.
3 Have a plan.
4 Know what the pieces are worth.
5 Develop quickly and well.
6 Control the center.
7 Keep your king safe.
8 Know when to trade pieces.
9 Think about the endgame.
10 Always be alert.

Don't rush. Take your time and be sure to study the examples carefully


Is there really a checkmate after 1... Bxf5?

I Suspect that after 3... Rxd5 4. f7 is strong enough:
[FEN "1r1r3k/7p/5Pb1/p2BpRpq/1pP5/1P1Q4/P5RP/7K w - - 0 1"]

1.Rgxg5 Bxf5 2. Qxf5 Qd1+ 3. Rg1 Rxd5 4. f7

The obvious threat is Qf6 mate. Starting with the variations in which black tries to cover f6 we have:

If 4...Rb6 then 5. f8=R#
If 4...Rd6 then 5. Qxe5 Rf6 6. Qxf6#

Since all variations leads to checkmate there is no way to cover f6 and black must resort to giving up the queen.
[FEN "1r1r3k/7p/5Pb1/p2BpRpq/1pP5/1P1Q4/P5RP/7K w - - 0 1"]

1.Rgxg5 Bxf5 2. Qxf5 Qd1+ 3. Rg1 Rxd5 4. f7 Qxg1 5. Kxg1

Yet again Qf6 is mate and obviously black cannot move the rook from the 8:th rank because f8 mate. If 5... Rd6 then 6. Qxe5 Rf6 7. Qxf6#. This leaves us with the one last try of Rd1+ (if Kg7 immediately then cxd5):
[FEN "1r1r3k/7p/5Pb1/p2BpRpq/1pP5/1P1Q4/P5RP/7K w - - 0 1"]

1.Rgxg5 Bxf5 2. Qxf5 Qd1+ 3. Rg1 Rxd5 4. f7 Qxg1 5. Kxg1 Rd1+ 6. Kg2 Kg7 7. Qxe5+ Kxf7 8. Qxb8

It is not a mate but undoubtedly white is winning


Should I play the Cozio defense deferred?

The Cozio defenses, both with 3....Nge7 (1) and 3....a6 4.Ba4 Nge7 (2), have been played by top grandmasters like Nakamura and Aronian. According to the Game Database of ChessTempo both variations are quite regularly played and equally popular: 1160 games for (1) and 703 games for (2).

Unsurprisingly, both variants are very similar. After (1) white usually plays 4.0-0 g6 5.c3 or 4.c3 immediately and after (2) white also often chooses the plan with c3: 5.c3 or 5.0-0 g6 6.c3. In this case, the variations of (1) and (2) usually transpose into each other.

However, it seems that there are some subtile differences between (1) and (2).

After (1), white has an extra option that is regularly played: 4.Nc3 g6 5.d4 exd4 6.Nd5 Bg7 7.Bg5. After (2), this idea is less common, as black answers 5.Nc3 with 5....d6. Now 6.d4 does not really work: 6....b5 7.Bb3 Nxd4 8.Nxd4 exd4 9.Qxd4? c5! and black wins the bishop after 10....c4.
In (2), white also has an extra option: after 3....a6 white can play 4.Bxc6.

      [FEN ""]
      [StartPly "5"]

      1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 (3...Nge7 4.Nc3 (4.O-O g6 5.c3) 4...g6 5.d4 exd4 6.Nd5 Bg7 7.Bg5) 4.Ba4 (4.Bxc6) Nge7  5.Nc3 (5.O-O g6 6.c3) d6 6.d4 b5 7.Bb3 Nxd4 8.Nxd4 exd4 9.Qxd4 c5


Order of pieces in one-dimensional array

They're both equally natural, they just start at a different square. But that choice is arbitrary anyway. Printing to a terminal is one of the least critical things a chess engine does with a board, and looping can go in the other direction just as easily.
If you want to be able to easily copy algorithms or code from examples or other engines (the license of which allows you to do that), it can be helpful to use the same conventions as most people do. But that's completely up to you.


Specialized tactics books to improve position analysis?

Larry Evans authored "What's the Best Move" in Chess Life for years.  It is what you describe - a position with multiple guess answers.  You're supposed to choose the right one, and say why.

He published a book with the same name.


It depends on the board position. Both have equal points. But in a closed position, i.e, when the mobility of our pieces are blocked by the opponents pieces, knights have advantage. On more open board positions, bishops have advantage.


The biggest things that stand out here is the power supply and hard drive. For the first, getting a cheap power supply tends to be a bad idea since if it breaks, it can bring down a lot of other stuff with it. 650W is plenty, but I'd recommend going with a more established brand like corsair or silverstone. For the hard drive, given that you can get a 1TB SSD for about $150, I would do so since it will mean you have plenty of room for a 6 man tablebase (syzygy).

Other than that, this should be a really good system for both leela and SF. If you want any help with optimal settings for lc0 performance, feel free to drop by the lc0 discord!


I'm assuming you did not know the name of its author.
When you post problems that aren't your own, you owe it to the composers to acknowledge their work. This is a problem by J. C. J. Wainwright, and is in two moves.  (It was first published in Alain C. White's Theory of Pawn Promotion, 1912.)
And, no, it has only one solution. (Added explanation: In the problem world, a 'solution' is the first move (the key move), and all subsequent variations that meet the limits of the stipulation, which in this case is 'self-mate in two moves'. Problems that have solutions with more than one key move are considered to be faulty, unless there are good reasons for the number of key moves.)
If you want to double check, try the on-line chess problem database YACPDB (https://www.yacpdb.org/), where a lot of chess problems have been recorded by users. Here is the link directly to it: https://www.yacpdb.org/#262458


The Swedish Variation of the Tarrasch Defense is the move 6...c4 in the line below. The name is also used for the same plan in slightly different positions with the same pawn structure.

[FEN ""]

1.d4 d5 2.c4 e6 3.Nc3 c5 {Tarrasch Defense} 4.cxd5 exd5 5.Nf3 Nc6 6.g3 c4 {Swedish Variation}

Its ECO code is D33. Black tries to capitalize on his queenside majority, while White is going to play e2-e4. I think theory considers the line dubious right now.

There is also the Göteborg variation in the Najdorf Sicilian, famous for its origin story. In 1955, one of the Interzonal tournaments was held in Göteborg, and in round 14 it happened that three Argentinian grandmasters (Panno, Pilnik and Najdorf) had black against three Soviet grandmasters (Geller, Spassky and Keres). All three reached the position below with the new move 9...g5 that the Argentinians prepared beforehand, and all three Soviet players reacted with the same piece sacrifice 11.Nxe6 and won.

[FEN ""]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Bg5 e6 7.f4 Be7 8.Qf3 h6 9.Bh4 g5 {Göteborg Variation} 10.fxg5 Nfd7 11.Nxe6 fxe6 12.Qh5+ Kf8 13.Bb5

I think it's considered drawish these days.


I am the author of pgn-extract. It would be easier to address the specifics of what you are trying to do via the personal email address included with the pgn-extract documentation. I would be happy to help.

David


Although solving proofgames is not that difficult, the large number of moves involved may seem impressive at first. Let me share you a few tips by showing how I solve a proofgame.
[Title "Étienne Dupuis, Problemesis 2001, PG in 13.5"]
[FEN "rn2k1nr/ppp3pp/4p3/8/4q3/1N1bb2P/PPPP1P1P/RNBQKB1R w KQq - 0 1"]

In this diagram, it is not obvious at first sight how white has spent 14 moves, as we count 3 for the Nb3, and 1 for Ph3. For black, we count a minimum of 2 moves for the queen, 2 for each bishop, and one for Pe6, for a total of 7 moves.
We need to find a hint, and here the hint is given by the white pawn h3. It must have captured a black piece, but which one? Since black is only missing pawns in the diagram and that no black pawn can reach h3, we must deduce that black has made a promotion.
Let us then enumerate various possibilities:

Black promoted a pawn on e1, and the promoted piece was captured on h3. This requires seven extra moves by black, yielding a total of 14 moves, one too many, hence impossible.
White pawn h3 captured a black piece and black promoted a pawn on e1 or g1 to replace this captured piece. This is the correct solution. No other promotion squares are possible since black can only capture one white piece.

Which black piece is an impostor?

The rooks and knights are too far away; it would take too many moves to reach h3 and bring back the promoted piece.
The dark square bishop cannot be captured on light colored square h3.
The light square bishop could, but cannot be promoted on dark squares e1 or g1.
The queen is the only candidate. It requires two moves to bring the queen to h3, and six moves to promote pawn d7 or f7 to a queen on e1 and bring it to e4.

At this stage, we have accounted for all thirteen black moves. We are not exactly sure if the queen played Qd8-h4-h3 or Qd8-d7-h3 or even Qd8-d3-h3 but we'll figure it out later.  We also do not know which black pawn promoted, but we know the one of the two did not move at all and was captured at home.
Turning to white's side, we must find moves to

Capture the d7 or f7 pawn.
Get the king out of the way for the black promotion to occur.

Getting the king out of the way not as easy as it looks like. Keeping in mind that black will promote a queen on e1, and then play Qe1-e4, the king must step at least two squares away and he cannot come back through e2. Hence he must come back from f1, indicating the Bf1 must also move out of the way. This requires at least 6 moves and the king would go at least to g1 or g2.
Who captured the black pawn?

The white pawn e2 can capture the d7 pawn, and then black would have played Qd8xPd7 before Qd7-h3 to get rid of the white pawn. This requires four white moves. However, it's not possible, as the f7 pawn would have no one to capture to reach e1.
A white knight can capture both. It would require two extra moves for Nb3 to capture on d7 and four extra moves to capture on f7.
White bishop and queen cannot capture as it would give check and black has no moves to spare.
White rook h1 could but would required eight moves. Impossible.

The missing black pawn was thus captured by the white knight.
It is now time to take out a chessboard and move the pieces along to try finding a solution keeping in minds all the deductions we have made.
Try moves, in any order. You will quickly stumble on an additional difficulty. To bring back the white king, we must shield the check from the Bd3. This bishop must be present on that square before black plays Qe1-e4, as the bishop played Bc8-f5-d3.
Who shields?

This shielding could be performed by the white bishop, in which case we need at least one extra move, if the bishop plays Bf1-a6-e2-f1 for example. But wait, Bd3 is in the way again. Hence if it's the bishop, it's from the other side and we need two extra moves.
Shielding could be performed by the white queen, also two extra moves.
Shielding can also be provided by the Nd3 for free, assuming it played Ng1-e2-d4-b3. However, this looks impossible, as who would capture the black pawn on d7 or f7?

With this additional observation, we get to eight moves for moving the white king out of the way (four for the king, two to move the Bf1 somewhere, and two for shielding on e2, by the queen or the bishop). This implies that the missing black pawn was captured by the white knight and that white Pe2 has not moved at all!
If it has not moved, white started by playing with the knight and black has no choice but to wait for the Pd7 to be captured; he cannot push Pe6 before playing Bc8-f5.
The solution is quickly found to be:
[Title "Étienne Dupuis, Problemesis 2001, PG in 13.5"]
[FEN ""]

1. Nf3 f5 2. Ne5 f4 3. Nxd7 f3 4. Nc5 Qd7 5. Nb3 Qh3 6. gxh3 Bf5 7. Bg2 Bd3 8. Kf1 fxe2+ 9. Kg1 e1=Q 10. Bf1 Qe4 11. Be2 e6 12. Kf1 Bc5 13. Ke1 Be3 14. Bf1

The reasoning made to find the solution gives us also a high confidence that the solution is unique, it cannot be something else.
Hopefully this extensive explanation will help you enjoy solving proof games!


Why is exchanging these knights the best move for white?

Despite the difference in evaluation, e4 is not really a mistake. White is a rook ahead and will win this game anyway, provided that they don't blunder. Perhaps Nxc4 leads to a victory a few moves faster, almost within the engine's search horizon; that's probably why the engine prefers it over e4.
However, even humans should prefer Nxc4. If you're this far ahead, you should exchange material; every exchange means less chance of threats from your opponent. A two-to-one advantage is much more decisive than an eight-to-seven. Black's knight is also more active than White's, that's another reason to exchange it. (That the engine indicates that Black should exchange knights after e4 is surprising, but it only underlines how bad Black's position actually is.)
The advice about exchanging when you're ahead is of course not a rule set in stone. You should always keep in mind the (potential) activity of the exchanged pieces. And if you're only a pawn ahead, that doesn't need to be decisive enough for the win. Rook endgames and endgames with opposite bishops are notoriously drawish, and there are more examples out there, but you don't have to worry about them for now.


It seems this is happening because for endgame positions, Stockfish uses its handcrafted eval function. This is why Stockfish still has a contempt setting, since it's unclear how to implement contempt with NNUE eval, but contempt is still applicable whenever Stockfish uses its handcrafted eval. The handcrafted eval can flatline, therefore Stockfish can flatline as well.


How did Taimanov lose this game to Karpov?

In the book "How Karpov Wins" by Edmar Mednis it is stated on page 174 that "White overstepped the time limit and lost". The book seems to be fully available on Google books and has a lot more analysis of the match.

https://books.google.com.au/books?id=x8MV0uoAJp0C


How do people 'see' the position in blindfolded games?

You certainly do not remember all the moves made.

Instead you remember the position on the board. In chess you have certain typical structures, so you don't really need to remember each and every piece's position. Instead you can for instance store the information: fianchettoed bishop to mean the very typical position of pawns on f2,g3,h2 bishop on g2 and knight on f3. Similarly you could store certain typical pawn chains. For instance in the French defence you could have white pawns on b2,c3, d4,e5 and black pawns opposing them on f7, e6, d5, c5, again you'd just store something like "closed French" .

Any player of reasonable strength is doing this automatically and subconsciously when doing calculations at regular chess as well.


Video of the Kasparov vs. Kaprov 2009 match in Valencia

I could find replay of live videos, but the commentary wasn't available..! :/
here you can stream those videos

Kasparov vs Karpov - Valencia, 2009


The move c5 is obviously anti-positional. So the purpose must be tactical.

[Title "Anti-positional c5"]
[FEN "1rb2rk1/5pb1/p1pp1np1/q6p/2PBP2P/2N2P2/PP1Q2P1/3RKB1R b - - 0 1"]

1... c5 2. Be3 Rxb2 3. Qxb2 Nxe4 4. Bd2 Nxd2 (4... Bxc3 5. fxe4) (4... Nxc3) 5. Kxd2

1…c5 2.Be3 Rxb2 3.Qxb2 Nxe4 is the obvious try. But after 4.Bd2 the position is pretty tricky because 4…Nd2 fails to 5.Kxd2, Bxc3 fails to fxe4 and Nxc3 steps into a selfpin. But the selfpin cannot be exploited by white because black has Re8+/Qe5+ coming up. This looks like a pretty crushing attack.

If white prefers to exchange the Bd4 for the Nf6, then the weak d5 square is more than balanced by the weak black squares in whites position. Bd4 is a much bigger threat than Nd5.


What's the best approach to adopting 1.d4?

If you want to start playing 1.d4 you should as first thing have a look at some theory about the Queen's gambit declined, as it is the most natural (and historical) way to play 1.d4: even if you will not end up adopting it in your repertoire, it will give you a taste of the major ideas behind the queen's pawn opening (minority attack usually against c5-c6, occupation of c-d files) and a sense of where the pieces belong.

After you do so you should start preparing for precise defences to play against (as in every opening although White has the first move, the order strongly depends on what Black plays next): in this respect you might have a look at any online database to find what is played most - but to spare the time, among all the most often played are:

Slav defence
semi-Slav
Indian defences (at least King's Indian and Grünfeld)

  Or is the Catalan a better start?

I myself do play the Catalan (when given the chance to do so) and therefore by all means I suggest you to look into it: it is however a heavy theoretical opening (from both sides) but it does provide White with a slight edge throughout the whole game (at best play).

  I am considering the London system against things

The London system is somehow more "natural" to play and it is lately gaining a lot of respect at high level (Carlsen and Aronian above all play it very often): you may find quite a few GM games to take examples from.

In general, as any other opening in chess, you cannot have your way around without putting some study into a few specific lines; however, there is a lot of free content online that you may surf, especially the Saint Louis Chess Club channel contains a lot of opening videos suitable for any level (according to me very thorough).


I disagree with all answers treating the gnat and elephant as allegory for players of varying skill level.

Rather, the actions of the gnat and elephant are the main point. Chess as a game with rules is not very broad. There are only six types of piece. Half the actual number of pieces are identical and have moves that are almost as simple as it is possible to be (with the exception of en passant, and even then, it is not nearly as complicated as many chess teachers and commentators make it out to be). The other pieces are moved in ways so simple a toddler can understand them. The board is a simple square only eight spaces wide. If one only looks from above the surface, chess is indeed narrow enough that a small insect could metaphorically fly across its whole.

However, in the centuries of its play, strategies and tactics have developed almost to excess. There is gambit and counter-gambit and analysis measured in the millions of pages, billions of words spent on dissecting just a few landmark matches together, let alone the game as a whole. If one considers the depth the game can present, it is indeed a sea deep enough to drown the metaphorical elephant in.


The two sources I'd depend upon to answer this question are actual games played by GM's (best), and engine analysis, carried to a depth of at least 24 ply (12 moves by each side).

Here's what I get:

Actual Games

Move     Games  Win %  Latest  Players
4 d4      2947  57.3    2016   Carlsen, Kasparov, Karjakin, Anand
4 Bb5      513  57.8    2016   Grischuk, Karjakin, Morozevich, Adams
4 Bc4      229  47.2    2016   Vallejo Pons, Movsesian, Lu SHanglei, Zhigalko
4 g3       153  48.4    2010   Mamedyarov, Romanishin, Galego, Biyiasas
4 h4        38  43.4    2012   Hamdouchi, Pilavov, Minasian, Pridorozhni

So, the move is pretty unpopular at the highest levels (about 1% of games), and since Black outscores White by 57%-43% in this line, it's no wonder.

Engine Analysis

Engine parameters: Stockfish 7, QuadCore AMD CPU using 4 Cores, Depth=25/39
Line Move    Eval
 a.  4 Bb5   0.17
 b.  4 d4    0.13
 c.  4 h3    0.13
 d.  4 Rb1   0.11
 e.  4 a4    0.10
 f.  4 Bc4   0.09
 g.  4 a3    0.03
 h.  4 Be2   0.01
 i.  4 d3    0.00

That's 9 lines that are better than 4 h4, and the 9th has an evaluation of dead equal, implying that the move 4 h4 must have a lower evaluation. Note that 4 h4 starts at among the top four moves until the engine reaches a depth of about 15-17 ply, and then falls off the map.  So the blowback seems to occur somewhere between move 11 and move 13.


I believe 3...Bf5 is preferred is because they want to play a Caro-Kann and not the French defense.  Black's main problem with his position after 4...e6 is the Bishop on c8.  White still has all his pieces on the first rank while Black has a Bishop developed so any loss of tempo is not really an issue here.


What's my next move against this Caro-Kann variant?

There are in fact quite a few mistakes on both sides, but I can't correct the AI, so this is for White:

3.Qc2 is already bad - it is does not contribute to the fight for the center (and this is a fast one, no time for slow moves). After pawns exchange on e4 black plays Nf6 with tempo and gains the "first move advantage".
6.h3 is slow in that it doesn't develop anything and doesn't stop any threat (Black's white bishop already chose a square which is not g4).
10.Nf3 is better than Ne2 - controls more critical square and looks over Black's weakened kingside.
13.Nb3 is a straight up blunder. 13...Bxb3 with threat on the queen forces 14.Qxb3 with time for Black's 14...hxg3 - up a piece.
15.Nc5 is winning. There are many variations here but after knights are exchanged you threaten 0-0-0 with check and some very strong tactics.
16.Kd2 is weak - centralizing the king while still in the midgame is risky and serves little purpose. Better is 0-0 at least.
17.Rhg1 while not a mistake seems uncalled for. The h rook seems better placed at e1 aiming at the half-open file and close to Black's king (with no castle rights). I think that Bxg2 for Black will be too slow as white has chances of trapping Black's Queen with moves like c4, Nc3 and a3 etc.
You have a better position, don't exchange pieces with 18.Be4. Something like c4 forces his bishop away, then follow with something along the lines of Rooks to e1 and d1, N to c3 (not necessarily in this order) and remember that if Black moves Q to a6 you have c5 with discovery of the bishop on the queen.


I would not normally answer this, but the real answer was deleted by its author for some reason, and is hidden. I also think that the original -3 for the question was more due to the original poster not being a native English speaker so I edited that too.

This is from the game Diaz Carias-Cordovil, 1966 Olympiad. Black resigned after 30.Bh6+, which is the first move of the solution. After Black’s forced Rxh6, White will play Qe5#.

 [Event "Olympiad-17 Final C"]
 [Site "Havana"]
 [Date "1966.11.13"]
 [Round "9"]
 [White "Diaz Carias, Salvador"]
 [Black "Cordovil, Joao Maria"]
 [Result "1-0"]
 [ECO "C50"]
 [StartPly "58"]
 [EventDate "1966.11.04"]
 [EventType "team-tourn"]
 [EventRounds "13"]
 [EventCountry "CUB"]
 [SourceTitle "MCD"]
 [WhiteTeam "Venezuela"]
 [BlackTeam "Portugal"]
 [WhiteTeamCountry "VEN"]
 [BlackTeamCountry "POR"]
 [FEN ""]

 1. e4 e5 2. Nf3 Nc6 3. Bb5 Be7 4. d4 d6 5. h3 exd4 6. Nxd4 Nf6 7. Nc3 O-O 8. O-O Nxe4 9. Nxc6 bxc6 10. Nxe4 d5 11. Bd3 dxe4 12. Bxe4 Rb8 13. Qf3 c5 14. Rd1 Bd6 15. Bd2 Qh4 16. Bc3 f5 17. Bd5+ Kh8 18. Re1 f4 19. Re2 h5 20. Rae1 Bg4 21. Re6 Bxe6 22. Rxe6 Rf6 23. Qe4 Rbf8 24. Rxf6 Rxf6 25. Qe8+ Kh7 26. Qg8+ Kh6 27. Be4 Rg6 28. Qh8+ Kg5 29. Bxg7 Be7 30. Bh6+ (30. Bh6+ Rxh6 31. Qe5#) 1-0


What's the main idea of this opening?

Main ideas for white:

surprise weapon as it is rarely played (since it is not all that good)
playing the Dutch opening with an extra tempo, but this is not a big deal IMO
avoiding opening theory as you can basically learn a "system" (certain position of pieces that you want to achieve) and follow this almost independent of what black plays
in some cases the pawn being already on f4 can be handy for kingside attacks

Basically there are three set ups:

stonewall with pawns on f4, e3, d4, c3; gives you good control of dark squares but weakens the light squares; Usually you only play this if black plays d5 at some point as otherwise black has the option to play something like d6 and e5 which is often unpleasant for the stonewall setup
fianchettoed bishop on  b2 often in combinations with pawns on e3 and f4. This gives you good control along the a1-h8 diagonal
fianchettoed bishop on g2. This can lead to king's indian like setups if you combine it with d3, e4.

In the end it depends whether you like the resulting positions. Check a few games from the database and look at the positions around move 10.

  Is the best counter of 1.f4 is 1...d5? Why 1...d5?

Yes, d5 is most popular and best. It takes control of the center, opens the way for the light squared bishop and is just a natural move. A reason not to play 1. ...d5 could be if you are worried about losing control of the dark squares in the center. In that case you could think to wait with d5, perhaps develop the bishop to g7 (which would work well against the white setup number "2" above) and leaving the option open to play d6 e5 later which would work well against the stonewall.

As a former 1. f4 player I would discourage you from playing this or any other off-beat opening if you want to be serious about chess. You can learn a lot more (and get better positions) if you play more normal openings.


How do I know what squares I need to control in a given position?

The best way to know what needs to be done is  to grasp how the pawn structure in the center affects the course of the game.  Read "The Art of The Middle Game" by Alexander Kotov and Paul Keres.  Kotov's chapter explaining the five possible pawn centers and how to proceed is the finest source ever written on this topic.

Those possible centers are: open, closed, fixed, mobile, and dynamic.

An open center is where only one or no K or Q pawns are still on the board. Fast attacks on the K and Q files are required and
immediate castling for safety.
A closed center is where pawns lock in mutual pawn chains such that neither side can advance a central pawn.  Wing attacks become necessary and castling can be delayed.
A fixed center is where the two K pawns face each other so neither can advance and the Q pawns are off the board.  Or, the Q pawns exist in the same manner and the K pawns are gone.  Play will result where each side tries to place a piece(usually a Knight) on the strong point protected by the central pawn such that the piece cannot be attacked by an enemy pawn advance. This is called an advanced outpost and when it occurs, victory for that player is likely.
A mobile center is when one side has both central pawns and the opponent has none.  The constant threat of these pawns advancing keeps the enemy too busy defending and lacking time to mount a counter-attack.
A dynamic center exists when the other four possibilities have not yet been decided. You should try to play for the type of center that will be stronger for your side.

Finally, look at your central pawns. If the K pawn is further advanced, look to attack on that side or in the center.  When the Q pawn is further out, attack on the queen side.  Kotov can provide much more detail.  Read the book!


What's the most prestigious chess competition broadcasted on TV?

I don't think there has been any televised chess tournaments in the English speaking world since the 90s with the Short-Kasparov matches.

From the 1970s through the 1980s there was a show on BBC2 called the Master Game. It seems that some of the episodes have been put on YouTube. See this article as well.

I really think that the major problem with televised chess tournaments in the decade that we live in right now is 3 fold:

There is not enough money in it to attract any but a niche network.
Serious chess coverage has migrated to the Internet and sites like PlayChess.com (from ChessBase), ICC, and Chess.com. Streaming video from these sites can reach a much wider audience than live broadcasts on BBC or ESPN.
The format is not very good for modern TV. The average viewer wants action. It's a sad comment on our society, but we live in the age of reality TV, not in an age where chess is actually appreciated.


I'd recommend starting off with traditional puzzle solving. Once you get to whatever your target range is and have a good accuracy rate (80-100%) and you can finish each of the puzzles in 45 seconds or less, move on to puzzle rush. Of course, when you get to 100 - 200 points below your target, and are accurate and quick, you could gradually start moving on to puzzle rush from the traditional puzzle solving.


Is there an easy way to find out the name of a variation?

My free, open-source software, pgn-extract, provides a file eco.pgn that provides names for ECO codes. This file can be used with pgn-extract to add ECO tags to game scores: see its -e flag. For instance, the tags it produces for the moves: 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 Be7 6.Re1 b5 7.Bb3 d6 8.c3 0-0 9.h3 Na5 10.Bc2 c5 11.d4 Nd7 * are:

[ECO "C96"]
[Opening "Ruy Lopez"]
[Variation "closed, Keres (...Nd7) defence"]

That might provides some degree of what you are looking for.


Would you look for mate, if tactics to win materials are easier to spot?

It makes no difference whether you deliver mate in 3, mate in 33 or your opponent resigns. On the score sheet and the tournament results you get the same score: 1-0. If you see a clear win then play it. Don't waste time looking for a "better" win. There is no such thing unless you are in a hurry to catch the last bus home.

Fixating about what the computer says in such positions is just silly. This is not just my opinion it is also shared by top players. I am currently reading Boris Gelfand's "Positional Decision Making in Chess" and he expresses this view in the book in positions where he is pursuing a positional winning plan and the computer analysis points out a quicker tactical win.


Funny games for 1 player with chess theme

find the most/least attacked square (or some other special square) on the board quickly
arranging pieces on the board with a certain condition (this can be the classic 8 queens problem, but also other pieces with other condition); perhaps not realistic enough for you, though IMO this can teach you a lot about how the pieces move
guess the opening based on some position
guess the move in a famous game; perhaps too close to chess for your purpose
some retrograde problems


In a ChessBase opening tree how can we put a column that displays the percent of time each move is played or a column that displays "Perf" minus "Av"?


50-move rule: only the last 50 or any consecutive 50?

She can claim a draw. Article 9.3 of the FIDE Laws of Chess, 2018, emphasis mine:

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 thelast 50 moves by eachplayer 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.

9.3.2 is the case you describe, where the moves have already been completed. 9.3.1 is the case that counts the move the player is about to make.
Edit: but you link to the other question. In real tournament chess, checkmate would certainly trump this -- checkmate ends the game, so the other player would never get another turn to claim a draw in. But problems are not tournament chess and they use their own conventions, like the famous rule that castling is allowed unless you can prove it isn't.


Would games played between two perfect players always end up on a draw?

The answer is currently unknown. If you don't consider the opening (generally the first 8-15 moves or so), strong AI like Stockfish will generally show a clear optimal move in any position, and the majority of openings tend to yield a draw in these computer matches. However, as there are an incredibly large variety of openings, and this number scales exponentially with the number of moves, it is infeasible, at least in the present, for us to find a definitive answer to this question.


What are the minimum required pieces for checkmate in 3d chess?

The following are minimum involving various pieces:

King + Queen
King + Rook + Any Piece
King + 2 Bishop
King + 2 Knight

This is only the theoretical minimum to actually mate. Whether or not it is possible to force a mate in this situation is a different question. You can see these mates by placing both kings in a corner, one on board 1, and the other on board 3.


(Opening) Traps whose only solution is to grab material

When I answered your other question and mentioned that a semi-bluff sacrifice works better if the best counter is to take the material, I actually had a specific opening line in mind.

I have never played the line with black myself, but I recommended it to a friend, who won some very nice games against stronger opposition.

The line I'm talking about is a sacrificial variation of the Löwenthal-Sicilian. You sac a pawn on your ninth move and continue with a rook sacrifice. The line I give below is just a sample line. There's quite a little tactical labyrinth for white to navigate. There is no direct refutation, only a better endgame for white in some line that I cannot remember. There are a lot of ways for white to go wrong, even if he doesn't take the rook for example, it can be quite tricky to get the knight out again.

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 e5 5. Nb5 a6 6. Nd6+ Bxd6
7. Qxd6 Qf6 8. Qd1 Qg6 9. Nc3 d5 10. Nxd5 Qxe4+ 11.Be3 Nd4 12.Nc7 Ke7
13. Nxa8 Nxc2 14. Kd2 Nxe3 15. fxe3 Nf6 16. Qb3 Rd8 17. Ke1 Ng4


Tricky continuation to the Fried Liver "refuted"

I mean, this is the main line and for a reason.
But I would be very surprised if most people's repertoire ended here, this is where it begins. The line goes
6.Bb5+ c6 7.dxc6 bxc6
And now White has a number of options. In all of them White stays up a pawn however Black gets some counter play. (and there isn't a great line to give back that pawn for initiative, not much to play for tricks)
The two main moves are 8.Be2 and 8.Bd3.
The line might continue 8.Be2 h6 9.Nf3 e4 10.Ne5 and Black will keep some lead in development and try to attack.
The idea of the other move then is to gain access to the e4 square, if 8.Bd3 h6 9.Ne4.
However this move blocks the d pawn so White will need to move that bishop again at a later time. Both of these lines can be very complicated and sharp so White has to be careful.


No.

With two moves as white, you can get out a maximum of one attacker to deliver a check.

With one move as black, there is no weakness you can create that leaves you unable to defend a check from any given attacking vector.


Chess.com has an analysis board meant for doing analysis with other people. But its available only for premium members. Also I am unsure if it has voice support in built when doing the analysis.

For the free alternative, its worth to look at FICS- It has a very cool feature for analysis called "examine", that combined with "mexamine" will give you exactly what you are looking for. Along with this, you could just setup a skype or gtalk (replace your fav free voip program here) for chatting with voice when you are examining the game. You could use Babaschess the free and best FICS client available.


A question about the time to evacuate a queen in a master game

Very good question and I'll try my best to answer properly. As you correctly pointed out, there would be no direct threat on the black queen after 11...exd4 12.exd4 because of the e2 bishop on the e-file (and no good discovery). But if we think further, what does the rook e1 really achieve for the white camp in the current position? Honestly, it's not doing much at all: protecting an already protected bishop and that's about it. Now considering the position after 11...exd4 12.exd4. In that case, the e1-rook is ideally placed on a open file and almost directly facing the black queen. Black would have to lose a tempo at some point by moving his queen and white could prepare an invasion on this e-file. Obviously it's a long-term plan but it's actually what strategy is all about!
To conclude, I would say that 11...exd4 is not a great move because it justify the previous white move 11.Re1.


It really depends on what area of the game you're focusing on improving.

If you want to improve general tactical vision, do a bunch of "cheap tactics". These are tactics that are easy and should take under a minute to solve, and doing many of them helps to improve your implicit tactical abilities during a game (you're able to see basic tactics quicker).

If you're working on your precision, studies are a good choice. Another option is to play through one grandmaster game on the board, and try to understand the main ideas in the game. For example, looking at a Karpov game can improve your pattern recognition for techniques on squeezing the opponent.

The point of studying chess is to make certain skills implicit knowledge... you should be able to subconsciously know certain things during a chess game. Doing cheap tactics improves your implicit tactical skills, and doing a study/looking at master games improves your implicit pattern recognition abilities.


Name of pawn struture in B42 Sicilian defense

According to Johan Hellsten-Play the Kan, there are six structures found in the Kan.

Classical Sicilian Structure
Hedgehog Structure
Enhanced Hedgehog Structure
Maroczy Bind
Aggressive Maroczy Bind
Classical Maroczy Bind


Can you solve this chess problem of a lone knight against numerous opposing pieces?

OK

The check must come from the knight (D'uh!)
The black king must be on c5 for the mate
The white king must be used to cover any empty squares to the right of the black king - thus the white king must move, thus there must be at least one non-checking move
On a non-checking move Black can try to release the prison by Ra4
The only way white can cover this is for the winning check to come from d3, as this covers b4 and the knight can not be captured there (unlike a6 after the rook moves)
When white makes the non-checking move he must be in a position to deal with threats from black, in particular the black queen, and checks from the black knight on c7 and the black bishop on h4
If on the non-checking move white plays Ke6 directly the knight check from d8 will break the prison
Thus the king must go to e4, attracting the black pawn to d5 with check, after which, if the black queen has been eliminated, the white king can go Ke6 Nd8+ Kd7 and it can't at that point be driven away

Putting this all together leads us to
[Event ""]
[Site ""]
[Date "????.??.??"]
[Round ""]
[White ""]
[Black ""]
[Result "1-0"]
[FEN "8/1nq5/bppp4/1p1k1K1N/1rrp3b/2pp2p1/8/n7 w - - 0 1"]

1.Nf4+ Kc5 2.Ne6+ Kd5 3.Nxc7+ Kc5 4.Nxa6+ Kd5 5.Nc7+ Kc5 6.Ne6+ Kd5 7.Nf4+
Kc5 8.Ke4 d5+ 9.Ke5 Bf6+ 10.Ke6 Nd8+ 11.Kd7 Ra4 12.Nxd3# 1-0

I think that's it, though I can't see at the moment what the Black Knight on a1 is doing


Where can I play this 2v2 chess variant online?

In America, we call this variant Bughouse, although most players allow place mate. Most online chess playing sites do have this variant.  Lichess, chess.com, chessclub, freechess, and chess.net.
Another variant is crazyhouse.  Here when you capture a piece, it changes color and becomes one of your drop pieces.  Unfortunately this also allow place mate.


Short answer:  Yes with minimax you have to search every move.

Minimax is not used due to the exponentially growing search which quickly becomes too big to be useful.  Think O(n2) sort functions.
Many concepts are used to help reduce the number of nodes the search function.  Transposition Tables, fail-safe, branch pruning...

https://web.archive.org/web/20071026090003/http://www.brucemo.com/compchess/programming/index.htm is the Gerbil chess engine with good explanations.

https://chessprogramming.wikispaces.com/Home is more general and discusses other algorithms, but is more technical and is closing soon.


I have the book "1.d4 Volume 2" by Grandmaster Boris Avrukh in front of me. Not the line you're looking at but Avrukh says 3.Bxb5 Bxe4 4.Nf3 Nf6 5.0-0 e6 6. c4 Be7 7.Nc3 Bb7 is perfectly playable for Black.

Avrukh's mainline vs the Polish defence is 1. d4 b5 2. e4 Bb7 3. Bd3 (solidifying the centre and aiming to prove the centre pawns are better than the wing pawns.) Nf6 (3...a6 4.Nf3 transposes to the St. George defense) 4. Nd2 e6 5. Ngf3 a6 6. 0-0 c5 7.dc Bxc5 8. e5 Nd5 9. Ne4 Be7 10. a4 b4 11.Nfd2! (heading for c4 and and freeing the Queen on the d1-h5 diagonal) ... and eventually += on move 18. The main plan for White is to play with pieces in the free space in the centre and possibly aim to attack on the Kingside or fill the holes left behind in Black's pawn structure. For more details buy the book.


How is this a winning position for white?

Qh6 threatens Qg7 mate, so Rg8 was the only way to defend.

Now if white finds a way for a rook to get to the h-line, Qxh7 Kxh7 Rh+ would be mate.

One idea would be 2.Rf3 Bxf3 3.gxf3 and then execute this idea with 4.Qxh7 and Ra2-h2. Unfortunately in this line 3…d5 attacks the h2 square and 4.Qxh7 Kxh7 5.Rh2 is foiled by 5…Qxh2.

So white plays 2.Rf4 first, this threatens g5 and then the execution. Therefore black forces the rook away with 2…e5. But now the Rf3-idea works because d5 no longer allows the queen to attack h2. No more way to prevent Qh7 and mate.

[FEN "r4r1k/pbq2p1p/1p1ppPp1/8/2P3P1/PP6/R2Q2P1/1B3R1K w KQkq - 0 1"]

1. Qh6 Rg8 2. Rf4 e5 3. Rf3 Bxf3 4. gxf3 d5 5.Qxh7 Kxh7 6.Rh2


White's non-e4 opening, do they all need a solid understanding of 1.d4 first?

There are c4/Nf3 lines where White never plays d4 (such as the reverse Dragon or the King's Indian Attack). They are solid but not top-tier openings. Additionally, they do not feature much diversity of pawn structures, which can impede learning.

Specifically after 1. c4 e5, this is less relevant because the game does not usually return to 1. d4 structures.

My advice to a player that is trying to improve would be to play 1. d4 for a while first, or learn enough of the d4 transpositions that there is no fear of being tricked.

If not trying to improve, then almost anything is a reasonable choice.


What are the winning chances of every pieces? (6men egtb)

I don't know a single source tabulating the winning percentages for all 6-piece endings, but at least some amount of summarizing information can probably be found scattered throughout Nunn's Secrets of ... Endings series of books, which are essentially translations from tablebase to human-usable information. But there is a spreadsheet available from Tamplin's chess endgame site, 3-5 Man Results and Maximals, that contains the percentage winning statistics across all < 6-man endgames. A sample of the data:

Endgame     wtm(=)  btm(=)      wtm(1-0)    btm(1-0)        wtm(0-1)    btm(0-1)

KK          100.00  100.00      0.00        0.00            0.00        0.00
KBK         100.00  100.00      0.00        0.00            0.00        0.00
KNK         100.00  100.00      0.00        0.00            0.00        0.00
KPK         23.49   41.91       76.51       58.09           0.00        0.00
KQK         0.00    10.32       100.00      89.68           0.00        0.00
KRK         0.00    9.97        100.00      90.03           0.00        0.00

...

KRNKP       1.53    17.10       98.45       78.39           0.01        4.51
KRNKQ       41.12   19.71       35.44       2.10            23.43       78.19
KRNKR       63.29   93.60       36.63       3.24            0.07        3.16

...

The first, third and fifth numerical columns give the percentage of white-to-move positions that are, respecitively, draws, white wins or black wins. And the other columns give similar information for the black-to-move positions. I'd think it unlikely that a similar table for 6-man positions doesn't already exist out there in the ether somewhere, but I don't know where such is located.

EDIT: Sure enough, the second edition of Nunn's Secrets of Pawnless Endings (and not the first edition which predated available 6-man tablebases) does go at least partly toward what you're after. There is a summary table (pp. 325-329) that, while not providing the numerical detail of the table above, does include for each 6-man piece combination at least an indication of whether it is generally won or drawn (presumably based on whether a majority of positions are theoretically won or not, as above), along with information about the longest win and longest reciprocal zugzwang for each ending.

To use your example, Nunn notes that KRBKNN is generally a win for White, while the longest win is 223 moves from the following position:

[fen "1K6/5BR1/2n5/2n2k2/8/8/8/8 w - - 0 1"]

Some of the endings also get discussed in the text. For instance, Nunn gives an optimal line from the above position and attempts to give annotations that make the very complex play involved understandable. (Partial spoiler: 1.Kc8! is the only winning move at the start.)


When playing a computer opponent what situations should I create to give myself a better chance of winning?

Interesting question, but it's a little bit hard to answer generally.  Any engine has its own quirks, but I'll try to give a few general hints and things to consider.

First, any modern engine on sufficiently fast hardware is going to wipe you off the board.  Even top GM's lose to engines with odds. 1  However, most engines have the hardest time in closed positions where long-term strategy is more important than tactics on any given move.  Games that are very closed (think classical KID lines) are won or lost based on chess understanding, and engines still don't truly understand chess.

One very interesting thing, however, is that some engines actually are vulnerable in extremely tactical games.  Most notably, engines are not always as good as humans when one side has a large attack.  Engines are notoriously bad at overestimating defensive resources and going into a line that is losing for the defender.  However, there is absolutely no margin for error in this case since a single misstep means the loss of the game.  This method (i.e. attacking the computer's king), is a very easy way to win against slightly weaker engines - for example the ones built into Windows and Macs (also the chess games on international flights, but those are really awful...).

To finish, probably the only way to have good chances against a strong machine are to memorize the moves ahead of time.  This might sound fantastic, but it's already been done.  The point is that the engine will spit out the exact same moves every game (under identical conditions), so it's possible to find a hole in the engine's repertoire and steer the game into this gap.

1. Rybka has played many odds matches - most notably against IM Meyer, GM Ehlvest, and GM Milov (who actually won the match!).


How many depth should require to get a draw decision?

Combinational Game Theory tells us that solved games will always result in a draw if both players play optimally.  With non-solved games like chess, one can make a "draw" assumption safely in the start position : no side has played a sub-optimal move ... or any move for that matter.

There are some famous players who have postulated this rigorously but when it comes to computer evaluations,  you have to take what the engine says with a grain of salt. They are great at analytical positions but are hit-and-miss in other places including the opening.

Most engines will give White an evaluation of around +0.30 at the start (3/10ths of a pawn) but that is not significant to predict that White will be able to sustain a draw if he tries to only play for one even at Master level play.  Nor has Engine vs. Engine competition ever seen a near perfect record of draws all the time. There is too much uncertainty when dealing with complexity like the kind in chess or Go.

In short, the answer to your question really should be "no". There is no such yardstick for draw-depth nor is there any value of attempting to statistically analyze a million games for inferences.

Practically, a draw occurs at the highest levels of play when there is mutually nothing worth playing for (without incurring undue risk).


Multimove variant rules with queen that does two moves in one

A variant that I have played for a while years ago is: white has just the king and the four central pawns (cdef), but is allowed two moves per turn. All usual rules, including en passant and promotion, apply. Check and checkmate are defined via "the player that takes the opposing king wins". The variant is surprisingly balanced, with black probably at a slight advantage (but with a lot more possibilities for blunders).

Given that this variant is playable as it is, I suppose that anything involving a double-moving queen would be ridiculously overpowered for its side.

The white king in this variant can 'make a nearby piece disappear' as you mentioned. It takes a few games to understand the strategies for the two sides: against someone of comparable level who has never played this variant, a player with some experience can often ask them to pick a side, beat them, propose a rematch with sides switched, and then proceed to beat them again. :)


Making the giuoco piano interesting as white

What about slow plan (1.e4, Nf3, Bc4, d3, c3, 0-0, Nd2), then depending on what the opponent does, you can play d4 or move the knight on d2 -> f1 -> g3 (and potentially f5) and make something happen on the king side.


Why is 5. f5 so necessary in the Dzindzi-Indian Opening/Modern Defense: Pterodactyl, Beefeater Variation?

You don't want a White pawn getting to e5, especially with a friend at f4.  White can let you have a c-pawn if he can achieve such a central dominance.

Also, without f5 it is awkward to develop the Ng8 -- you notice none of the variations you show have Nf6.  But now after f5, Nf6 will grip the e4 square.   Thus White often plays e4 anyway!


Why is the centre of the board considered important in chess?

While (e4, d4, e5, d5) are generally regarded as the central squares, the same principle can sometimes be extended to the adjacent squares like (c4, c5, d3, d6, e3, e6, f4, f5). So we have a kind of central polygon -

Controlling the center is not an end in itself but a means to an end. The end results could be any combination of the following-

1. Greater influence over the board.

Normally, if you control the center, then your pieces have more control over the whole board in general. Thus, a knight centralized on e5 generally controls more important squares than a knight passively placed, say, on a4.

Recommended Game:

Karpov vs Kasparov World Championship Match (1985), Game 16 - Kasparov anchors a Black knight on d3 which was famously described as the "octupus", controlling several key squares in White's position and greatly influencing the entire board. White's knights on the other hand are pushed to passive squares like a4 and b1, exerting almost no control over the board.

  [FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
  [White "Karpov"]
  [Black "Kasparov"]

  1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nb5 d6 6. c4 Nf6 7. N1c3 a6
  8. Na3 d5 9. cxd5 exd5 10. exd5 Nb4 11. Be2 Bc5 12. O-O O-O 13. Bf3 Bf5
  14. Bg5 Re8 15. Qd2 b5 16. Rad1 Nd3 17. Nab1 h6 18. Bh4 b4 19. Na4 Bd6
  20. Bg3 Rc8 21. b3 g5 22. Bxd6 Qxd6 23. g3 Nd7 24. Bg2 Qf6 25. a3 a5
  26. axb4 axb4 27. Qa2 Bg6 28. d6 g4 29. Qd2 Kg7 30. f3 Qxd6 31. fxg4 Qd4
  32. Kh1 Nf6 33. Rf4 Ne4 34. Qxd3 Nf2 35. Rxf2 Bxd3 36. Rfd2 Qe3 37. Rxd3 Rc1
  38. Nb2 Qf2 39. Nd2 Rxd1 40. Nxd1 Re1 0-1

2. Greater mobility of pieces.

Often, if the central pawns are not advanced two squares, they can hinder the bishops from development. They provide less space for the pieces to move. If these pawns are advanced to the central squares, then the mobility of the pieces is greatly enhanced. Thus, e2-e4 frees the bishop on f1 and d2-d4 does the same for the bishop on c1. Besides, these moves also make room for the queen on d1 and later for the rooks to come into the game on the d or e files if they have been opened.

Recommended Game:

Paul Morphy vs James McConnell, 1849 - Morphy follows basic opening principles; develops pieces towards the center, advances pawns to e4 and d4, his bishops come to life and the Black queen is at the mercy of his centralized pieces.

  [FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
  [White "Morphy"]
  [Black "McConnell"]

  1. e4 e5 2. Nf3 Qf6 3. Nc3 c6 4. d4 exd4 5. e5 Qg6 6. Bd3 Qxg2 7. Rg1 Qh3
  8. Rg3 Qh5 9. Rg5 Qh3 10. Bf1 Qe6 11. Nxd4 Qe7 12. Ne4 h6 13. Nf5 Qe6 14. Nfd6 Bxd6
  15. Nxd6 Kd8 16. Bc4 Qe7 17. Nxf7 Kc7 18. Qd6 Qxd6 19. exd6 Kb6 20. Be3 c5
  21. Bxc5 Ka5 22. Rg3 b5 23. Ra3 1-0

3. Restricted mobility of enemy pieces.

Suppose white manages to place both pawns on d4 and e4. This makes it difficult for the Black bishops to find good squares like c5 or f5. They thus have to remain passive or try a fianchetto, which might not always be convenient. Also, the pawns on d4 and e4 restrict and also have the ability to attack the Black knights which might normally be developed on c6 or f6. This constant potential to threaten the Black knights can make it difficult for Black to develop pieces comfortably.

Recommended Game:

Karpov vs Kasparov World Championship 1986, Game 5. - Karpov demonstrates how pawns in the center can restrict a fianchettoed Bishop.

  [FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
  [White "Karpov"]
  [Black "Kasparov"]

  1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. Bf4 Bg7 5. e3 c5 6. dxc5 Qa5 7. Rc1 Ne4 8. cxd5 Nxc3
  9. Qd2 Qxa2 10. bxc3 Qxd2 11. Kxd2 Nd7 12. Bb5 O-O 13. Bxd7 Bxd7 14. e4 f5 15. e5 e6
  16. c4 Rfc8 17. c6 bxc6 18. d6 c5 19. h4 h6 20. Nh3 a5 21. f3 a4 22. Rhe1 a3
  23. Nf2 a2 24. Nd3 Ra3 25. Ra1 g5 26. hxg5 hxg5 27. Bxg5 Kf7 28. Bf4 Rb8 29. Rec1 Bc6
  30. Rc3 Ra5 31. Rc2 Rba8 32. Nc1 1-0

4. Pawns move closer to the enemy king.

Generally, in an attack on the enemy king, it is important to have a few pawns near the enemy king to make it difficult for the opposing pieces to defend the position. If the Black king (for example) castles to the kingside, then it usually helps White to have a pawn on e5, because then Black cannot place a knight on f6, which is the most natural defensive position for the knight on the kingside.

Recommended Game:

Fischer vs Myagmarsuren, 1967 - Bobby Fischer fixes a pawn on e5 to drive the Black knight from f6 and then proceeds to win with a kingside attack in instructive fashion.

  [FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
  [White "Fischer"]
  [Black "Myagmarsuren"]

  1. e4 e6 2. d3 d5 3. Nd2 Nf6 4. g3 c5 5. Bg2 Nc6 6. Ngf3 Be7 7. O-O O-O
  8. e5 Nd7 9. Re1 b5 10. Nf1 b4 11. h4 a5 12. Bf4 a4 13. a3 bxa3 14. bxa3 Na5
  15. Ne3 Ba6 16. Bh3 d4 17. Nf1 Nb6 18. Ng5 Nd5 19. Bd2 Bxg5 20. Bxg5 Qd7
  21. Qh5 Rfc8 22. Nd2 Nc3 23. Bf6 Qe8 24. Ne4 g6 25. Qg5 Nxe4 26. Rxe4 c4
  27. h5 cxd3 28. Rh4 Ra7 29. Bg2 dxc2 30. Qh6 Qf8 31. Qxh7 1-0

5. A favorable exchange of pawns in the center leaving the enemy camp with weaknesses.

Normally, when pawns are placed in the center, the opponent has to challenge them at some point in the future. This can often lead to favorable pawn exchanges and may lead to isolated pawns or backward pawns in the enemy camp, which can be vulnerable in some positions.

Recommended Game:

Rubinstein vs Salwe, 1908 - Here, Rubinstein creates a backward pawn on c6 and then masterfully exploits it.

   [FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
   [White "Rubinstein, Akiba"]
   [Black "Salwe, Georg"]

   1. d4 d5 2. Nf3 c5 3. c4 e6 4. cxd5 exd5 5. Nc3 Nf6 6. g3 Nc6 7. Bg2 cxd4
   8. Nxd4 Qb6 9. Nxc6 bxc6 10. O-O Be7 11. Na4 Qb5 12. Be3 O-O 13. Rc1 Bg4
   14. f3 Be6 15. Bc5 Rfe8 16. Rf2 Nd7 17. Bxe7 Rxe7 18. Qd4 Ree8 19. Bf1 Rec8
   20. e3 Qb7 21. Nc5 Nxc5 22. Rxc5 Rc7 23. Rfc2 Qb6 24. b4 a6 25. Ra5 Rb8
   26. a3 Ra7 27. Rxc6 Qxc6 28. Qxa7 Ra8 29. Qc5 Qb7 30. Kf2 h5 31. Be2 g6
   32. Qd6 Qc8 33. Rc5 Qb7 34. h4 a5 35. Rc7 Qb8 36. b5 a4 37. b6 Ra5 38. b7 1-0

As I mentioned, these are the end results that a side tries to achieve by controlling the center. If the end result is already achieved, or if it can be obtained in a better way, then there is no need to control the center.


During the 1984-1985 Karpov-Kasparov match, what was Karpov's initial weight?

That's a lot, if validated. Karpov was rather slight at the time, something around 60kg or less, so that represents something under 20% of his body weight.

And actually, that's consistent with other facts, given that was a 50+ game match. Fabiano Caruana says he can drop around 10% of his body weight during a difficult tournament. (Said to an ESPN reporter.) Robert Sapolsky, a Stanford researcher, has measured some players at burning 6000 calories per day in a tournament.

Another unverified data point is Rustam Kasimdzhanov losing 17 pounds at the 2004 championship.

A lot was made of this recently, made "sexy" because Magnus Carlson sought the advice of Olympic trainers for his physical conditioning, but it's not a new discovery. Petrosian would also drop a lot of weight during the championship match cycle, and other champions like Botvinnik and Spassky made getting in physical condition an important part of their match preparation.

ESPN, NPR ("The Chess Grandmaster's Diet"), Men's Health, seems like every magazine got in on it last year.

I don't have anything verifiable on the Karpov bit, but the other work I've seen, taken with the comment from Caruana, means I'll accept it as true until someone can disprove it. It's been verified to happen to players other than Karpov, so why not him?


Two or three games is very little to say much. You will not even have encountered all of the main lines after ....a6. Generally the Najdorf Sicilian is rather tactical and opening mistakes can quickly lead to a loss. In some lines white has a very straightforward plan of pushing its h and g pawns and checkmating black.

Practising tactics and studying the opening thoroughly is essential.
For more useful advice it would help to know your playing strength and to see one of your games


White to force the end of the game in two moves

Very nice puzzle! Looks like the solution is as follows:

[FEN "8/8/6p1/5pP1/5P1K/5PpP/4p2p/2Q2Bkr w - - 0 1"]

1. Qe1 g2 (1... exf1=Q 2. Kxg3 Qxe1#) (1... exf1=R 2. Qxg3#) (1... exf1=N 2. Qf2+ Kxf2 (2... gxf2)) (1... exf1=B 2. Kxg3) 2. Bxe2# 1-0

Interestingly, in the different lines, following results are achieved:

White gives a checkmate
Black gives a checkmate
White is stalemated
Black is stalemated


How to play vs 1.e4 e5 2.Nf3 Nc6 3.d4 Nxd4?

After 1.e4 e5 2.Nf3 Nc6 3.d4 Nxd4, both 4.Nxd4 and 4.Nxe5 seem to lead to an advantage for white. However, it's hard to tell which of the two options is best. Therefore it's a matter of taste.

4.Nxd4 exd4 5.Qxd4 transposes to the Scottish main line, where black played the inferior 4....Nxd4. This option is the easiest for white: white stays in his repertoire after 3....exd4, unless he wanted to play a Scottish gambit line, e.g. 4.Bc4 or 4.c3.

However, 4.Nxe5 also yields an advantage for white. After 4....Nc6 5.Nxc6, white has an extra tempo compared to 3....exd4 4.Nxd4 Nf6 5.Nxc6. Instead, black can retreat with 4....Ne6. According to the Game Database of ChessTempo, 5.Bc4 is the most popular reply, but 5.g3 seems an interesting alternative.

Edit: It's important to mention that, after 4.Nxe5, 4....Bc5 is a mistake. One refutation is 5.Nxf7, given by Evargalo, as white regains the piece after 5....Kxf7 6.Qh5+. Instead, black should complicate matters by 5....Qe7 or 5....Qh4. According to Stockfish 9, play should continue with 6.Nxh8 Qxe4+ 7.Be3 Nxc2+ 8.Kd2. Another refutation is the natural 5.Be3. Once again the Nxf7-idea comes into play: 5....Ne6 6.Bxc5 Nxc5 7.Nxf7 Kxf7 8.Qh5+. Black can avoid material losses by 5....Qh4, as 6.Bxd4 is answered by 6....Qxe4+. Nevertheless, white obtains a clear advantage after 6.Nc3 Ne6 7.g3 Qf6 8.Nc4.

      [StartPly "5"]

      [FEN ""]
      1.e4 e5 2.Nf3 Nc6 3.d4 Nxd4 (3...exd4 4.Nxd4 (4.c3)(4.Bc4) Nxd4 (4...Nf6 5.Nxc6) 5.Qxd4) 4.Nxe5 (4.Nxd4 exd4 5.Qxd4) Bc5? (4...Nc6 5.Nxc6)(4...Ne6 5.Bc4 (5.g3)) 5.Be3 (5.Nxf7 Qe7 (5...Kxf7 6.Qh5+)(5...Qh4 6.Nxh8 Qxe4+) 6.Nxh8 Qxe4+ 7.Be3 Nxc2+ 8.Kd2 Bxe3+ 9.fxe3 Nxa1 10.Nc3) Qh4 (5...Ne6 6.Bxc5 Nxc5 7.Nxf7 Kxf7 8.Qh5+) 6.Nc3 (6.Bxd4 Qxe4+) Ne6 7.g3 Qf6 8.Nc4


What is the longest sequence of consecutive captures in a FIDE rated game?

According to Tim Krabbé, the record is 17 moves and it's tied between the following games:

Blodig - Wimmer, Germany 1988

[FEN ""]
[StartPly "23"]
[Site "Germany"]
[Date "1988"]
[Result "0-1"]
[White "Blodig"]
[Black "Wimmer"]

1.g3 e5 2.Bg2 d5 3.d3 Nf6 4.Nf3 Nc6 5.O-O h6 6.c3 Be6 7.Nbd2 Qd7 8.b4 a6 9.a4 Bd6 10.Bb2 O-O 11.b5 Na5 12.c4 dxc4 13.dxc4 Nxc4 14.Nxc4 Bxc4 15.Nxe5 Bxe5 16.Bxe5 Qxd1 17.Rfxd1 axb5 18.Bxb7 Rxa4 19.Rxa4 bxa4 20.Bxc7 Bxe2 21.Rd4 Re8 22.Bd6 Rd8 23.Be5 Rxd4 24.Bxd4 a3 25.f3 a2 26.Kf2 Bc4 27.Bc6 Nh7 28.h4 Nf8 29.Ba4 Ne6 30.Ba1 Nc5 31.Bc2 Bb3 32.Bf5 g6 33.Bh3 Be6 34.Bxe6 fxe6 35.Ke3 Nb3 0-1

Rudd - Roberson, British ch, Swansea 2006

[FEN ""]
[Event "British Championship"]
[Site "Swansea WLS"]
[Date "2006.08.11"]
[EventDate "2006.08.07"]
[Round "5"]
[Result "1/2-1/2"]
[White "Jack Rudd"]
[Black "Peter T Roberson"]
[ECO "A65"]
[WhiteElo "2328"]
[BlackElo "2122"]
[PlyCount "288"]
[StartPly "29"]

1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6
7. Nge2 Bg7 8. Ng3 O-O 9. Be2 Na6 10. O-O Nc7 11. Bg5 Re8
12. Qd2 a6 13. a4 Bd7 14. f4 b5 15. e5 dxe5 16. fxe5 Rxe5
17. axb5 Bxb5 18. Bxb5 Nxb5 19. Nxb5 axb5 20. Rxa8 Qxa8
21. Bxf6 Bxf6 22. Rxf6 Qxd5 23. Qxd5 Rxd5 24. Ne4 Re5 25. Nc3
b4 26. Na4 c4 27. Rb6 c3 28. bxc3 bxc3 29. Nxc3 Re7 30. Kf2
Kg7 31. Kf3 h5 32. Ne4 Ra7 33. Rb3 Re7 34. g3 Ra7 35. Nd6 Ra6
36. Ne8+ Kf8 37. Rb8 Ke7 38. Nc7 Ra5 39. Nb5 Ra2 40. h4 Ra1
41. Rb7+ Ke6 42. Nd4+ Kf6 43. Kg2 Ra2+ 44. Kh3 Rf2 45. Rb3 Kg7
46. Nf3 Ra2 47. Ng5 Ra7 48. Kg2 Re7 49. Kf3 Ra7 50. Rb4 Re7
51. Ne4 Ra7 52. Nd6 Ra6 53. Rd4 Ra1 54. Rf4 Ra3+ 55. Kg2 Ra2+
56. Rf2 Ra7 57. Rb2 Ra6 58. Ne4 Ra7 59. Kf3 Re7 60. Kf4 Kg8
61. Nd6 Re6 62. Rb8+ Kg7 63. Ne8+ Kh6 64. Rd8 Re7 65. Nd6 Kg7
66. Re8 Ra7 67. Rb8 Ra4+ 68. Ke5 Ra5+ 69. Rb5 Ra3 70. Rb7 Rf3
71. Ne4 Re3 72. Kd4 Re1 73. Ng5 Rf1 74. Ke5 Kf8 75. Kd6 Rd1+
76. Kc7 Rc1+ 77. Kd8 Rd1+ 78. Rd7 Rf1 79. Ne4 Ra1 80. Nd6 Rf1
81. Re7 Rf2 82. Re4 Rd2 83. Kd7 Ra2 84. g4 hxg4 85. Rxg4 Kg7
86. Rf4 Ra7+ 87. Kc6 Re7 88. Kd5 f5 89. Ra4 Kf6 90. Ra6 Kg7
91. h5 Re1 92. hxg6 Kxg6 93. Ne4+ Kg7 94. Ng3 Rb1 95. Nxf5+
Kf7 96. Ke5 Re1+ 97. Kf4 Rf1+ 98. Ke5 Re1+ 99. Kd5 Rd1+
100. Nd4 Ke7 101. Re6+ Kf7 102. Re2 Ra1 103. Kd6 Ra6+ 104. Nc6
Ra1 105. Ne5+ Kf6 106. Rf2+ Kg5 107. Ke6 Ra6+ 108. Kf7 Ra7+
109. Kg8 Ra8+ 110. Kg7 Ra7+ 111. Nf7+ Kg4 112. Rf6 Rb7
113. Kg6 Kg3 114. Nd6 Ra7 115. Kg5 Ra5+ 116. Nf5+ Kf3 117. Re6
Rb5 118. Re3+ Kf2 119. Ra3 Rb4 120. Ne3 Rb5+ 121. Kh4 Rb4+
122. Kh3 Rb8 123. Nf5 Rh8+ 124. Kg4 Rg8+ 125. Kf4 Ke2 126. Rc3
Kd2 127. Rc7 Kd3 128. Ke5 Re8+ 129. Kd5 Rd8+ 130. Nd6 Rh8
131. Nf7 Rh5+ 132. Ne5+ Ke3 133. Rc2 Rh8 134. Rc3+ Kd2
135. Rg3 Rd8+ 136. Ke4 Re8 137. Rd3+ Kc2 138. Rd5 Rh8 139. Nf3
Re8+ 140. Kd4 Rg8 141. Rc5+ Kb3 142. Kd3 Rg3 143. Rf5 Rh3
144. Rf4 Rg3 1/2-1/2


Be2 makes no threat, leaves g2 undefended, and seals in the Queen.  Black has Bg4 which prevents 6... Bg4 7.Nf3 Bxf3 8.gxf3 as this leaves White with crummy pawns.

Black also has Be7 followed by Bh4, exploiting White's weak black Kingside squares.

Finally, Black also can move either Knight. Black simply has no problems.


I don't think there is an official listing of previous title regulations. You just have to glean what you can from internet searches.

Here's what I found.

  From the 1st July 2009 the following changes will apply to FIDE
  titles.

  1) Only one player can having a rating uplift, instead of two.

  2) The rating of the player uplifted has been reduced by 50 points.
  Hence the uplift for a GM norm is now 2200 (was 2250), IM norm 2050
  (was 2100).

  3) Performance requirements and requirements of the opponents’ ratings
  have been changed to even tens. i.e GM norm used to be 2601
  performance, now 2600, minimum average rating of opponents used to be
  2381, now 2380.

  4) For any given title norm at least 1/3 of a players opponents must
  hold that title. i.e. For a GM norm 1/3 must hold GM title. Whilst in
  comparison to the old regulations this makes no change to a 9 round
  event, it would effect a 12 round event where 4 GM's would be required
  (used to be 3).

Going back to the beginning, this chessbase article fills in some of the history - https://en.chessbase.com/post/a-gm-is-a-gm--fide-title-devaluation-270613

Summarizing -

When grandmaster titles were first awarded in 1950, they were given to the world champion Mikhail Botvinnik and all those who had qualified or been seeded in the inaugural Candidates Tournament: Isaac Boleslavsky, Igor Bondarevsky, David Bronstein, Max Euwe, Reuben Fine, Salo Flohr, Paul Keres, Alexander Kotov, Andor Lilienthal, Miguel Najdorf, Samuel Reshevsky, Vasily Smyslov, Gideon Ståhlberg, and László Szabó.

The title was also given to older living players who were recognized as having been world class at their peak: Ossip Bernstein, Oldrich Duras, Ernst Grünfeld, Borislav Kostic, Grigory Levenfish, Géza Maróczy, Jacques Mieses, Viacheslav Ragozin, Akiba Rubinstein, Friedrich Sämisch, Savielly Tartakower, and Milan Vidmar.

In 1957 the regulations were set to give the GM title automatically to the world champion and to any player qualifying from the Interzonal tournament to play in the Candidates.

In 1965  the rules were tightened up so that a player had to score 40% in the Candidates Tournament, or reach the quarter finals of the Candidates Matches to get the title.

In 1970 the modern system was initiated whereby you had to get your rating up to a certain ELO rating - 2450 - and to get 3 "norms" in a 3 year period. A "norm" was a rating performance of 2551 or above in a suitable tournament.

Since 1970 that basic formula has been tweaked with changes to the ratings involved and the type and makeup of qualifying tournaments in terms of how many of the other players must be from different federations, how many have the GM title, what the time controls are, how many players, etc., etc.


Your GUI design is bad. I'd just do this:

White pawn x3
White queen x1
Black pawn x2
....

Draw a chess piece and add a number to it's top-right corner. It's like how iOS and Android show the number of unread SMS messages you have.

Nobody wants to count the number of pawns in your panel. Just add a number.


That indicates slightly more than just the time control:

6SS indicates a 6-round Swiss system tournament.
40/120 indicates that each side will have 120 minutes to make the first 40 moves of the game.
sd30 indicates that after the first 40-move time control is met, each side will have an additional 30 minutes for the remainder of the game ("sd" = sudden death).
d5 indicates that there will be a 5-second delay on each move, during which one's clock will not yet have started to tick.


Average ELO of Tradewise Gibraltar Chess Festival 2016?

If I didn't mess up my script the average Elo of the Gibraltar Masters 2016 is 2321.64.

That is category III and nowhere near a super tournament.

But of course if you only look at the top seeds the average is very comparable to super tournaments. (The top nine would be category XXI)

Basically after the first 4-5 rounds you have a full fledged super tournament going on at first 5 boards.


What is the advantage in knowing the fastest winning sequence if I can win with few more moves than fastest sequence?

There is no advantage if your goal is to improve your OTB rating.   The time wasted solving a problem in fewer moves would be better spent learning things that you could use in your games.


Is it wise to resign a game if the win is only apparent too many moves ahead?

The time to resign is when think your opponent will win.  Against a beginner, I would never resign, because they will most probably blunder and lose.  Against a decent club player, I could resign after being a rook down in a lost position.  Against a GM, I would resign after the 12th move if I thought I had a bad position (it's a good learning possibility to see the technique).

I find it insulting to not resign when your opponent has a won game. (An exception can be made for cases like checkmating with a knight and bishop).

In the case of a computer, it can only do as it's programmed to do.  (Although humans now stop the game when an endgame database position has been reached to prevent the human from making a mistake the the computer looks up in a book.  This is cheating if a human did it, why not the computer?)  I don't think that the computer should resign this early, but he late should the computer resign?


As of 2016 There are a few Android based e-ink readers, most notably by Onyx and a whole bunch of rebrands ranging in size from 6 inches to 9.7 inches.

I highly recommend checking out mobileread.com for all e-ink reader related information.

Usually they do not run the latest Android (i think 4.4.2 is about as good as it gets).

Another minus is that they do not run the most powerful CPUs(to both save on costs and also to preserve power). Still for running Stockfish they should be good enough.


How relevant is historical performance for Elo rating?

Let's say a FIDE player is rated 1800, and has k=20. Every month this player plays in one 4-game tournament, in which they play against opponents all rated exactly 2000, and scores exactly 50%. How fast does the rating converge?
After six months, they would be rated 1898. After one year, the player's rating would be 1949. After 18 months,the rating would be 1975, and after two years, it would be 1987. So it seems that the player is getting approximately halfway to their performance rating every six months or so in this scenario.
After 32 months, the player would be rated 1997, and after that the rating no longer moves because a rating difference of 3 has an expected score of 50% according to the table FIDE uses.


1.e4 Nc6 2.d4 d5:

  3.Nc3

scores best for White according to my database and it is the move I play.

3...dxe4

Your opponent can go into the French Defense with 3...e6, but this is not a good French with the N on c6 blocking the c-pawn.

4.d5 Ne5 is the most common.

5.Qd4 Ng6

Now White can consider Qxe4, h2-h4, f3... White has many aggressive options.

The safe 6.Qxe4 Nf6 7.Qa4+ Bd7 8.Qb3 continues to give Black problems.
The pawn sac offer of f2-f3 seems to have clear compensation based on the development advantage it gives.  But the problem with non-queen moves is that they allow Black to play e7-e5 which is close to equal.

  Alternatively 2.Nf3

a common line is 1.e4 Nc6 2.Nf3 offering Black to return to a standard opening with 2...e5.  If 2...d5 you get an odd Scandinvian/Center-counter.  Black usually plays 2...d6 and after 3.d4 Bg4 4.Bb5 a6 5.Bxc6 White scores better.


Can you capture a pawn en passant with a king?

An en passant capture is a move that involves pawns, exclusively. In particular, the king is not allowed to capture en passant.

From Wikipedia (link):

  It is a special pawn capture, that can only occur immediately after a pawn moves two ranks forward from its starting position, and an enemy pawn could have captured it had the pawn moved only one square forward. The opponent captures the just-moved pawn "as it passes" through the first square. The resulting position is the same as if the pawn had moved only one square forward and the enemy pawn had captured it normally.