How to map file and rank to a square number in TSCP? How can I map file and rank numbers (0-7) to a square number in Tom Kerrigan's Simple Chess Program?

I know how to do the conversion from square number to rank and file, but not the other way around.

The conversions from square to row and column are defined in defs.h as:

#define ROW(x) (x >> 3)
#define COL(x) (x & 7)

so you can apply the inverse to generate the square number:

(row << 3) | col


What is the theory behind Bishop's Opening, Philidor Counter-Attack? What is the theory for this opening for black?

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

1. e4 e5 2. Bc4 c6

I've started playing the Bishop's Opening because it is something different, but I had not seen this counter play before.

It seems weak, because--although it has the advantages of an opening like Caro-Kann by grabbing control over the center--black immediately loses defense of his king pawn (Nc6 is unplayable). Despite this, it seems a solid opening for black.

Black cannot play Nc6 at the moment, that is true. However, it doesn't look like White can exploit this immediately, either.

Black will answer 3 Nf3 by ...d5, gaining tempo on the Bc4 that he can then use to either defend e5 (d7 is open for the knight, at the very least) or counter-pressure e4 (which is equally weak as e5). The whole motive is similar to the classical center attack in the Italian (c3 + d4).

Trading the pawns (4 exd5 cxd5) opens c6 for the knight again and doesn't look very attractive as it yields the center to Black. 5 Bb5+ is toothless, Black will reply ...Bd7 and then take back on d7 with his knight (or simply play Nc6 if the white bishop retreats now). Immediately retreating (by 4 Bb3) doesn't look very good either, Black will gain the initiative.

Of course, White has other options for his third move. 3 d4 is a similar attempt to attack e5. Black can reply 3...d5 again, which leads to a very complicated position. But again, e4 is just as weak as e5 and swapping away e4 opens c6 for the knight. No clear advantage for any side.

Against 3 Nc3 (prevents 3...d5, but doesn't attack e5), Black has time to play 3...Bc5 , followed by 4...d6 (e5 is safe) and he will achieve something similar to a Giuoco Pianissimo Reversed - which is not too bad, really.

So, yeah: Totally playable in my opinion.

Disclaimer: I'm not an actual expert in this opening.


How defend against rooks in 7th rank? I find it hard to defend against rooks placed in 7th rank.
What are the possible defense options?
Please share your knowledge.

[FEN "r4rk1/p1pRR1pp/1p6/8/8/P6P/1P3PP1/6K1 w - - 0 1"]

1.Rxg7+ Kh8
2.Rxh7+ Kg8
3.Rdg7#

In general, prophylaxis can be used to prevent the rooks getting on the 7th. This is the preferred defense; common challenging moves are to contest open columns with your own rooks, or to guard the 7th rank squares with your minor pieces.

In the case that the rooks are already on the 7th, you should secure the most urgent threats (where your king is or where most of your loose material is), and then trade off rooks or go on the offensive.

Hope that helps!


unusual line slav defense [FEN ""]

1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.Nf3

Here we reach slav defense main line and theory goes with 4...e6

As a way to avoid theory as black I used to play in blitz 4...g6, goes with bishop fianchetto and castle.

As white I'm a d4 player and although not many people deviate 4...e6 with 4...g6 this could happen.

Searching in professional games I didn't see many games with 4...g6.

My question is: How white proceed after 4...g6? (there must be a reason why professionals rare play this move)

According to this database:

The next move for white will be:

5.e3 with 40% of win, 46% of draw and 14% of lose. (3538 games were played like that)
5.cxd5 with 48.5% of win, 41.5% of draw. (344 games were played like that)

Example for a game which start like this:

[Event "1st Rottal Open 2017"]
[Site "Pfarrkirchen GER"]
[Round "6.1"]
[Date "2017.4.17"]
[White "Haba, Petr"]
[Black "Riediger, Martin"]
[Result "1/2-1/2"]

[FEN ""]
1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 g6 5.cxd5 cxd5 6.Bf4 a6 7.h3 Bg7 8.e3 Nc6 9.Be2 O-O 10.O-O Bf5 11.Rc1 Ne4 12.Na4 Bd7 13.Qb3 b5 14.Nc5 Nxc5 15.Rxc5 e6 16.Bd6 Re8 17.Ne5 Nxe5 18.dxe5 f6 19.Bc7 Qe7 20.Bd6 Qd8 21.Bc7 Qe7 22.Bd6 1/2-1/2


Between 1.d4 and 1.Nf3, what is the White first move that generally leads to the most solid, positional, slow, closed, strategic and quiet positions? I'm a ~1750 Elo player and I've been thinking of switching my opening repertoire for White.

So my question is: between 1.d4 and 1.Nf3, what is the White first move that generally leads to the most solid, positional, slow, closed, strategic and quiet positions?

.

I am only including 1. d4 and 1. Nf3 in the question, and not 1. e4 and 1. c4.

I think 1. e4 is clearly on average sharper and more tactical than 1. d4 or 1. Nf3 because of the Sicilian (although maybe there is the Rossolimo and the Moscow variations which look pretty slow and solid, I'm not sure...). Also, I hate having a Pawn on e4 not protected by any other of my Pawn during the entire game, I have to constantly watch out for it..

And 1. c4 can also get very sharp and tactical because of 1... e5, the Sicilian Reversed.

.

Of course I know that any of those first moves can lead to any type of positions. But I want to know ON AVERAGE which leads to the least tactical ones.
Just like there are a few quiet and positional lines in the Sicilian, but on average the Sicilian is considered to be a highly tactical opening, certainly not a quiet opening.

And I don't want to get into solid, strategic and quiet positions because I suck at tactics (it's not the case, I played the Sicilian for 3 years, and did more than 5000 tactical puzzles). It's just because I love slow manoeuvring, I want to be able to be perfectly relaxed while playing, and not get into insane positions and stress out knowing that one single inaccuracy can be fatal.
Maybe you still think that playing wild games full of tactics everywhere will make me improve faster, but I don't care because I don't want to become a Grandmaster, I just want to enjoy the game, and I'll enjoy it more if I can get the positions which I personally like (solid, quiet and strategic positions).

I'm a ~1750 Elo player and I've been thinking of switching my opening repertoire for White. ... And I don't want to get into solid, strategic and quiet positions because I suck at tactics (it's not the case, I played the Sicilian for 3 years, and did more than 5000 tactical puzzles). ... Maybe you still think that playing wild games full of tactics everywhere will make me improve faster ...

First of all, it is exactly the quiet positions that help improve a player, not the tactical ones. Everybody learn tactics, anyone can find mate in five when playing their own game so the only thing you should do is just keep solving puzzles and that's it. Your tactical skill will always be high, but never at the level of a GM. Why? Because some sacrifices are positional and are made with the intent of getting long-term compensation instead of mating in five or returning the sacrifices material. In order to master these, you need a strong understanding of middlegame positions that may arise from the openings you play.

Furthermore, with "quiet" play, you actually play chess instead of doing mindless checking for tactics, which will greatly help you improve. In quiet positions, you must still calculate and check for tactics, but you also must frequently decide which pieces are good to exchange and which are not ( this is very helpful when transitioning into endgame -> you would be surprised how often "tactical players" of high skill make banal mistakes in this area! ), you must take into account endgames that may arise and above all, you always have to evaluate pawn structure that may arise after every move played. To master "quiet" games you will need a lot of work on endgames, pawn structures and middlegame plans, but you will get so much in return -> you will be able to effortlessly grind down lesser players, outplay "tactical players" of equal rating, and offer very strong resistance against stronger players. So I understand exactly where you appeal for closed games comes from and will try to help you as best as I can. And for the record, playing "quiet" games will make you become GM faster than playing tactical games. GMs/IMs do not make mistakes in pure tactical positions, those are just well explored and every master knows them by heart. Tell me when was the last time you saw Sicilian Najdorf in World Championship match?? You will always see 1.d4 because of reasons that are too broad to be posted here...

  So my question is: between 1.d4 and 1.Nf3, what is the White first move that generally leads to the most solid, positional, slow, closed, strategic and quiet positions?

These two overlap, technically you can find all the 1.Nf3 openings transpose into certain opening lines that start with 1.d4.

The only sharp opening that is dangerous for your style of play is King's Indian Defense, since it requires a lot of learning, is sharp and some lines are extremely theoretical. Other nonsense, like BenOni or Chigorin defense are just rubbish and should not phase you ( BenOni is nearly refuted with Taimanov attack and you can bypass the Chigorin defense by simply playing Nf3 before you hit with c4 ) since most of the time White has an advantage or can simply dodge them altogether.

The problem with 1.Nf3 approach is that you can not battle Queen's Gambit Declined with favorable version of the Exchange variation and there are other openings where early Nf3 reduces your chances for obtaining an advantage. Still, this move offers you big practical chances to outplay your opponent with transpositional tricks. I haven't played active chess for quite some time ( 10+ years to be precise ) but let me show you on a small example what I am talking about:

[Title "Black wants to play with full center, but is tricked into passive position"]
[fen ""]

1.Nf3 Nc6 2.d4!

and Black has blocked his c-pawn thus condemning himself to passive play if he enters pawn structures with d5+e6, so he should aim for e5+d6 pawn structure with 2...d6 but White may play 3.Bf4, keeping e5 square in his control. The tactical shot 3...Nxd4 fails due to 4.Qxd4! e5 5.Nxe5 dxe5 6.Qxe5+ +-. He could try to go for e5 with 2..Bg4 but then simple e3 will force him to exchange the bishop for a knight in order to enforce ...e5. Although you allowed ...e5 you got bishop pair in return. This is known as trading one advantage for another and is important concept in positional play. With 1.Nf3 most of your games will be of this type, but you will have to cover a lot of theory so you can take the maximum transpositional tricks can offer you. Furthermore, you you have a chance to dodge the sharp lines:

[Title "White dodges King's Indian Defense"]
[fen ""]

1.Nf3 Nf6 2.g3 g6 3.Bg2 Bg7 4.O-O O-O 5.d3!? d6

And now you could play c4, e4 or even c3 going for b4 and action on the queenside. The position is stable for both sides so the player with broader knowledge and higher creativity will prevail. The point of 1.Nf3 is that you must have a vast opening knowledge and strong grasp of typical middlegame positions like Isolated or Hanging pawns, various exchange lines ( like in QGD, Slav, French defense and so on...) and even main lines, so you can successfully decide in which direction to steer the game.

As for 1.d4, things are different. This move reduces the amount of work you must invest in learning the pawn structures/middlegame plans and variations, but offers Black great chances to sharpen the game. Various gambits, King's Indian defense and so on are now a real option. You would have to accept that sometimes you will have to play mind-blowing, wild tactical games, you initially wished to dodge. Your biggest problem will be Nimzo-Indian defense since it scores very well against 1.d4, but you can dodge it by playing Nf3 instead of Nc3. Although the subtle move order can take away best response for Black, you too must pay the price. Black may play Queen's Indian defense, which gives White a small advantage but is considered drawish, or he can trick you and choose to play Queen's Gambit since the most dangerous reply -> the Exchange variation after cxd5, is harmless for him since you have Nf3 instead of Ne2.

In my opinion, 1.Nf3 will offer you solid and strategic positions you seek, but you will have to work harder and be ready to make more draws than wins since most of the time the best options for White can be bypassed by Black.

Comparing 1.d4 vs 1.Nf3 further would be too broad, so I will ask you to leave a comment if you need further help. In the end, here are some books I would recommend:

For 1.d4:

B.Avrukh-Grandmaster repertoire 1;
B.Avrukh-Grandmaster repertoire 2;
B.Avrukh-Grandmaster repertoire 8;
B.Avrukh-Grandmaster repertoire 9;
B.Avrukh-Grandmaster repertoire 10;
B.Avruhk-Grandmaster repertoire 11;
L.Shandorff-Playing the Queens Gambit ( second edition! );

For 1.Nf3:

A.Khalifman-Opening for White according to Kramnik ( all of the books in the series! );

Good luck and best regards.


Can white win in this almost 20 year old puzzle? It's White to move-can they force a win?. The left bottom is a1 as usual.
[FEN "4k2r/6p1/p4pKb/p2N3p/p7/p5Q1/p1n5/qrn5 w - - 9 9"]

Note for people who saw an earlier version: the position was edited (including a swap of the colors) for a more beautiful puzzle by Laska's suggestions. The answer has now been fixed accordingly.
History: I came up with this puzzle when I was a student, almost 20 years ago. It was published in the magazine of my local chess club, but nobody found the answer. A friend popularized it with his new chess-friends after he emigrated to Canada.

The solution is

   1. Qc7 followed by Qe7, Qf7 or Qc8 mate (depending on Black's second move).

This works because

   Black can't castle because either his king or rook on h8 have moved already. As Brian Towers notes, the black a-pawns need to have captured 10 white pieces and/or pawns; there are enough pieces missing, but capturing the white e-pawn (or to the right) doesn't bring you any closer to the a-file. So, one white pawn on the queenside must have been captured on another file; this is possible via promotion, but since there's just one black piece missing (a white-squared bishop) the promotion could have happened on the d-, e-, f-, or h-file. The pawn has either attacked the black king at f7 or d7, or it promoted on e8, forcing the black King to move in all cases. Or it promoted on h8, forcing the black rook to move. Another possibility, as @Laska noted, is that the e-pawn captures the black bishop on the d-file and is captured itself before promotion; however, we only need a single capture on the d-file, and the original white d-pawn must be captured too.


Marshall vs. Queen Endgame In a game of "Sort of Almost Chess", the variant from Mr. Betza that replaces one of the queens with a Marshall (the Rook+Knight compound, also known as the Chancellor, or the Empress in Fairy Chess circles), this surfaced as a possible endgame that was narrowly avoided by a slightly controversial promotion by Black. The Marshall and Queen are represented in the diagram as Knight and Bishop, respectively (given that they can both move as rooks).

    [Date "2018.06.26"]
[Round "-"]
[White "NN"]
[Black "James"]
[Result "?"]
 [FEN "7B/8/6K1/8/8/1k6/6P1/n7 w - - 0 1"]

Given that Black's to move, I'm wondering if it's possible for either side to get a win from this position. A Black Queen (the promotion that actually took place instead of this position) is a forced win for Black with careful play, and Marshall vs. Marshall is almost certainly a draw, but the similar yet different power of the pieces here makes it a complex problem.

Since my Stockfish fork for fairy chess variants already supports Almost Chess, I added Sort of Almost Chess with both sides having all promotion options (which is what you seem to imply in your question).

I ran a search on the given position up to depth 50 with the commands below:

setoption name hash value 1024
setoption name multipv value 30
setoption name UCI_Variant value sortofalmost
position fen 7Q/8/6K1/8/8/1k6/6P1/c7 b - - 0 1
go depth 50

The results below state that white is winning (latest in 23 moves) irrespective of black's next move. Going through some of the variations in the output it seems relatively clear that the chancellor has no way to give a perpetual, so white is able to advance the pawn and finally either promote or force the exchange of queen and chancellor.

info depth 50 seldepth 47 multipv 1 score mate -23 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1a4 h8f6 b3a2 f6e6 a2b2 e6e2 b2c1 e2e3 c1c2 g6f7 a4a5 e3e2 c2b3 e2d3 b3a4 d3d4 a4b3 d4b6 b3a4 b6a5 a4a5 g2g4 a5a6 f7f6 a6b7 g4g5 b7a7 g5g6 a7a6 f6e5 a6b5 g6g7 b5c4 g7g8q c4c3 e5e4 c3c2 e4d4 c2b2 d4c4 b2c2 g8g2 c2d1 c4d3 d1e1 g2g1
info depth 50 seldepth 47 multipv 2 score mate -23 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1e1 h8b8 b3a2 b8a7 a2b3 a7b6 b3c4 b6a6 c4b4 a6d6 b4c4 g2g4 e1a1 d6c6 c4b4 c6e4 b4b3 e4d3 b3b2 d3d4 b2a2 d4a1 a2a1 g6f5 a1b2 f5e5 b2b1 g4g5 b1c1 g5g6 c1d1 g6g7 d1e2 g7g8q e2f3 g8b3 f3e2 e5e4 e2f2 e4f4 f2g2 b3c2 g2f1 f4f3 f1e1 c2c1
info depth 50 seldepth 45 multipv 3 score mate -22 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1g1 h8b8 b3c2 b8c7 c2d3 c7d6 d3e4 d6b4 e4d3 g2g4 g1h1 b4d6 d3e3 d6e5 e3f2 e5f4 f2g1 f4c1 g1h2 c1h1 h2h1 g6f5 h1g2 g4g5 g2f2 g5g6 f2f3 g6g7 f3e3 f5e5 e3d3 g7g8q d3e3 g8b3 e3e2 e5e4 e2f2 e4f4 f2g2 b3c2 g2f1 f4f3 f1e1 c2c1
info depth 50 seldepth 45 multipv 4 score mate -22 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1f1 h8f6 f1g3 g6f7 g3h1 g2g4 h1h7 f7g6 h7h3 g4g5 b3a3 g6f7 a3b4 g5g6 h3h6 f7e6 h6g4 g6g7 b4c4 e6f7 g4g1 f6c6 c4d3 c6g6 g1g6 f7g6 d3e4 g6f6 e4f4 g7g8q f4e4 g8c4 e4f3 c4d3 f3g2 d3e2 g2h3 e2f2 h3g4 f2e3 g4h4 f6f5 h4h5 e3h3
info depth 50 seldepth 45 multipv 5 score mate -22 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1d1 h8f6 b3a4 f6c6 a4b4 c6b6 b4c4 g2g4 d1e1 b6d6 e1a1 d6c6 c4b4 c6e4 b4b3 e4d3 b3b2 d3d4 b2b1 d4a1 b1a1 g6f5 a1b2 f5e5 b2b1 g4g5 b1c1 g5g6 c1d1 g6g7 d1e2 g7g8q e2f3 g8b3 f3e2 e5e4 e2f2 e4f4 f2g2 b3c2 g2g1 f4f3 g1h1 c2g2
info depth 50 seldepth 43 multipv 6 score mate -21 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1c1 h8f6 b3a3 f6d6 a3b3 d6d7 c1c5 d7d1 b3a2 d1d2 a2b3 d2e3 b3b4 e3c5 b4c5 g2g4 c5d6 g6f7 d6c6 g4g5 c6d7 g5g6 d7d6 f7f6 d6d5 g6g7 d5e4 g7g8q e4e3 f6e5 e3f3 g8b3 f3e2 e5e4 e2f2 e4f4 f2g2 b3c2 g2g1 f4f3 g1h1 c2g2
info depth 50 seldepth 43 multipv 7 score mate -20 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1a6 h8f6 a6a4 g6f5 b3a2 f6e6 a2a1 e6e1 a1a2 e1d2 a2a3 d2d3 a3b4 d3e4 b4b5 e4a4 b5a4 g2g4 a4a3 f5e5 a3b2 g4g5 b2b1 g5g6 b1c1 g6g7 c1d2 e5e4 d2c2 e4d4 c2b3 g7g8q b3b2 d4c4 b2c2 g8g2 c2d1 c4d3 d1e1 g2g1
info depth 50 seldepth 41 multipv 8 score mate -20 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1c2 h8b8 b3a2 b8a8 a2b3 a8d5 b3b2 d5e4 c2c1 e4b4 b2c2 b4c5 c2b1 c5c1 b1c1 g2g4 c1d2 g6f5 d2d1 g4g5 d1e2 g5g6 e2e3 g6g7 e3e2 f5e5 e2e3 g7g8q e3f3 g8b3 f3e2 e5e4 e2f2 e4f4 f2g2 b3c2 g2g1 f4f3 g1h1 c2g2
info depth 50 seldepth 39 multipv 9 score mate -19 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1a5 h8b8 b3a2 b8d6 a5a4 d6d5 a2a3 d5d3 a3b2 d3b5 b2a3 b5a4 a3a4 g6f6 a4b5 g2g4 b5b6 g4g5 b6a7 g5g6 a7a6 f6e5 a6b5 g6g7 b5c4 g7g8q c4c3 e5e4 c3c2 e4d4 c2b2 d4c4 b2c2 g8g2 c2d1 c4d3 d1e1 g2g1
info depth 50 seldepth 31 multipv 10 score mate -15 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1a3 h8h3 b3b4 h3a3 b4a3 g2g4 a3b4 g4g5 b4c5 g6f6 c5c6 g5g6 c6d6 g6g7 d6c5 f6e5 c5c4 g7g8q c4c3 e5e4 c3c2 e4d4 c2b2 d4c4 b2c2 g8g2 c2d1 c4d3 d1e1 g2g1
info depth 50 seldepth 31 multipv 11 score mate -15 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1a2 h8g8 b3b2 g8a2 b2a2 g2g4 a2b3 g4g5 b3b4 g6f5 b4b5 f5e5 b5b6 g5g6 b6c5 g6g7 c5c4 g7g8q c4c3 e5e4 c3c2 e4d4 c2b2 d4c4 b2c2 g8g2 c2d1 c4d3 d1e1 g2g1
info depth 50 seldepth 31 multipv 12 score mate -15 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1b1 h8b8 b3c2 b8b1 c2b1 g2g4 b1c2 g4g5 c2d3 g6f5 d3e2 g5g6 e2e3 g6g7 e3e2 f5e5 e2e3 g7g8q e3f3 g8b3 f3e2 e5e4 e2f2 e4f4 f2g2 b3c2 g2g1 f4f3 g1h1 c2g2
info depth 50 seldepth 29 multipv 13 score mate -14 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv b3a2 h8a1 a2a1 g2g4 a1b2 g4g5 b2a1 g6f6 a1b1 g5g6 b1a2 g6g7 a2b2 g7g8q b2c2 g8g3 c2b2 f6e5 b2a2 e5d4 a2b2 g3c3 b2a2 c3b4 a2a1 d4c3 a1a2 b4b2
info depth 50 seldepth 21 multipv 14 score mate -10 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1a7 h8b8 a7b7 b8b7 b3c4 g6f5 c4c5 f5e5 c5c4 b7f3 c4b5 f3c3 b5a6 e5d6 a6a7 c3b2 a7a8 d6c6 a8a7 b2b7
info depth 50 seldepth 19 multipv 15 score mate -9 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1h1 h8h1 b3c3 h1h4 c3b3 h4d4 b3c2 g6f5 c2b3 f5e4 b3a3 e4d3 a3b3 d4b6 b3a2 d3c2 a2a1 b6b1
info depth 50 seldepth 19 multipv 16 score mate -9 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv a1a8 h8a8 b3b4 a8c6 b4b3 c6b5 b3c2 g6f5 c2d2 f5e4 d2c3 e4e3 c3c2 b5b4 c2c1 e3d3 c1d1 b4b1
info depth 50 seldepth 17 multipv 17 score mate -8 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv b3b4 h8a1 b4c4 g6f5 c4d3 a1a4 d3e2 a4d4 e2f1 f5g4 f1e2 g4g3 e2e1 g3f3 e1f1 d4a1
info depth 50 seldepth 17 multipv 18 score mate -8 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv b3a3 h8a1 a3b3 a1d4 b3c2 g6f5 c2b3 f5e4 b3a3 e4d3 a3b3 d4b6 b3a2 d3c2 a2a1 b6b1
info depth 50 seldepth 17 multipv 19 score mate -8 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv b3c2 h8a1 c2d3 g6f5 d3c4 a1a4 c4d3 f5f4 d3c3 f4e3 c3b2 e3d3 b2b1 d3c3 b1c1 a4a1
info depth 50 seldepth 17 multipv 20 score mate -8 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv b3a4 h8a1 a4b3 a1d4 b3c2 g6f5 c2b3 f5e4 b3a3 e4d3 a3b3 d4b6 b3a2 d3c2 a2a1 b6b1
info depth 50 seldepth 17 multipv 21 score mate -8 nodes 860106805 nps 1814762 hashfull 355 tbhits 0 time 473950 pv b3c4 h8a1 c4b3 a1d4 b3c2 g6f5 c2b3 f5e4 b3a3 e4d3 a3b3 d4b6 b3a2 d3c2 a2a1 b6b1


As Black, what is the fastest way to beat Gnu Chess on easy mode? This is more of a puzzle. As far as I can ascertain, Gnu-Chess on easy mode always plays the same movesm What is the least amount of moves required to beat Gnu Chess on easy mode? Just to clarify, you are playing as Black, Gnu Chess is playing as White.


Why does the FIDE rating table go beyond 400? The FIDE rating regulations say:

8.5 Determining the rating change for a rated player
8.51 For each game played against a rated player, determine the difference in rating between the player and his opponent, D. [...]
8.54 A difference in rating of more than 400 points shall be counted for rating purposes as though it were a difference of 400 points.
8.55
(a) Use table 8.1(b) to determine the player’s score probability PD [...]

But table 8.1b (which seems to be used only for this purpose) contains entries that go higher than 400. What use are those entries? Why are they there in the first place if they cannot be used?

Why are they there in the first place if they cannot be used?

They were there in the first place because they were used. The 400 point rule came later.

  What use are those entries?

They provide interesting historical context which makes it easier to answer questions like this.

Perhaps a better question would be, why are they still there, or why weren't they removed when the 400 point rule was introduced. There are two obvious answers:

Inertia. It would take effort to remove them
Efficiency. If the 400 point rule is rescinded at some stage then the entries required are already there.


Is it OK to look at the list of played moves during the game to determine the status of the 50 move rule? There are some positions in which you need to know how many moves have been played without pawn move or capture. For example:

[FEN "1R5K/8/8/8/8/8/7R/k7 w - - 98 1000"]

(1R5K/8/8/8/8/8/7R/k7 w - - 98 1000)

Here, white must play Ra2 or Rb1 to force a capture within 1 move. If this is not done the game is drawn due to the 50 move rule.

If the 50 move rule was not a concern it would be an easy mate in 2.

Of course it is very hard to remember how many moves have passed. Is white allowed to look at the scoresheet and count the number of moves during the game?

The rules for this and how it works are spelled out in articles 9.3, 9.4 and 9.5 of the FIDE Laws of Chess. They don't mention whether or not you are allowed to check your scoresheet to do this because you are always allowed to check your scoresheet. You would be very foolish to not check your scoresheet first because there are penalties for an incorrect claim.

Here are articles 93, 9.4 and 9.5 of the FIDE Laws of Chess:

  9.3 The game is drawn, upon a correct claim by a player having the move, if:
  9.3.1 he writes his move, which cannot be changed, on his scoresheet and declares to the arbiter his intention to make this move which will
  result in the last 50 moves by each player having been made without
  the movement of any pawn and without any capture, or
  9.3.2 the last 50 moves by each player have been completed without the movement of any pawn and without any capture.
  9.4 If the player touches a piece as in Article 4.3, he loses the right to claim a draw under Article 9.2 or 9.3 on that move.
  9.5.1 If a player claims a draw under Article 9.2 or 9.3, he or the arbiter shall stop the chessclock (see Article 6.12.1 or 6.12.2). He
  is not allowed to withdraw his claim.
  9.5.2 If the claim is found to be correct, the game is immediately drawn.
  9.5.3 If the claim is found to be incorrect, the arbiter shall add two minutes to the opponent’s remaining thinking time. Then the game shall
  continue. If the claim was based on an intended move, this move must
  be made in accordance with Articles 3 and 4.


Dvoretsky's Endgame Manual vs Fundamental Chess Endings I want to know what the differences are between "Dvoretsky's Endgame Manual" and "Fundamental Chess Endings".

I want to know also if these books are compatible, I mean, if I buy for example "Dvoretsky's Endgame Manual", it would be useless to buy "Fundamental Chess Endings" because they are very similar in his ideas or the examples that they show, or it is OK to have both books? I'm a 2100+ FIDE rated player, and that's why I want to buy these books, because I think they are for my level already.

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

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

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


What are key squares and critical squares? What is the best definition of key squares in king and pawn vs king endgame theory? Please provide graphics if possible. Is there a difference between "key squares" and "critical squares," or are these terms interchangeable?

The terms key squares and critical squares are sometimes used interchangeably in chess literature in king vs king and pawn endgames.

A square is called a key square when the occupation of it by the attacking king will secure a win regardless of which side is to move.

2nd through 4th Ranks
In this example, the key squares for the White pawn are e6, f6, and g6.
[FEN "8/8/8/8/5P2/8/8/8 w - - 0 1"]

A Pawn that Crosses the 5th Rank has More Key Squares
In this example, the pawn on f5 has two sets of key squares: e6, f6, and g6, as well as e7, f7, and g7. If White's king can occupy any of those 6 squares, they can secure the win.
[FEN "8/8/8/5P2/8/8/8/8 w - - 0 1"]

The Rooks Pawn are Exceptions
These positions show a draw regardless of which side has the move.
[FEN "5k1K/8/7P/8/8/8/8/8 w - - 0 1"]

[FEN "7k/8/7K/7P/8/8/8/8 w - - 0 1"]

In the first position, Black can simply shuffle his king between f7 and f8 and White makes no progress. In the second position, the move sequences 1. Kg6 Kg8 2. h6 K8 3. h7 stalemate. The sequence 1... Kg8 `. Kg6 Kh8 3. h6 Kg8 4. h7+ Kh8 with a stalemate, or loss of the pawn.
Related Topics
The Opposition
Rule of the Square
Resources
Wikipedia on key squares
Endgame Simulations (against a computer)
ChessDiary #2 - Monday Endgame Pawn Endgame - Key Squares


Why is it illegal to move into check? In chess, it is against the rules to move into check, or to not move out of check. But why? Obviously, if you went against this rule, you'd immediately lose. But it seems strange to make it illegal to lose in such a way.

Is there a reason for this rule? Is there a reason that chess ends with checkmate rather than capturing the king?

It is basically just a shortcut that cuts the game short by one move once the outcome is obvious. According to Wikipedia, "In early Sanskrit chess (c. 500–700) the king could be captured and this ended the game. The Persians (c. 700–800) introduced the idea of warning that the king was under attack (announcing check in modern terminology). This was done to avoid the early and accidental end of a game. Later the Persians added the additional rule that a king could not be moved into check or left in check. As a result, the king could not be captured."

The one difference from "real chess" that it does cause is actually rather significant. In a normal game of chess, stalemate is declared a draw, as Black has no legal move. For example:

[title "Black to move"]
[FEN "4k3/4P3/4K3/8/8/8/8/8 w - - 0 1"]

If moving into check were allowed and capturing the king ended the game, Black could move his king in this situation and White would capture it, winning the game. Opinions vary, even among grandmasters, whether stalemate is a good rule for chess or not, but in any case it is a consequence of the check rules, and a large fraction of draws are the result of it. Once again Wikipedia has a good summary of the consequences for endgame theory of abolishing the stalemate rule and making capturing the king the requirement to win the game.


Is this the quickest way to clearing the board to two kings? Is 21 moves the least needed to get board down to 2 kings?

[FEN ""]
1. e4 d5 exd5 Qxd5 Qh5 Qxa2 Qxh7 Qxa1 Qxh8 Qxb1 Qxg8 Qxb2 Qxg7 Qxc2 Qxf8 Kd7 Qxf7 Qxc1 Ke2 Qxd2 Kf3 Qxf2 Ke4 Qxf1 Qxe7 Kc6 Qxc7 Kb5 Qxc8 Qxg1 Qxb8 Qxh1 Qxa8 Qxh2 Qxa7 Qxg2 Kd4 Qd5 Kxd5 b6 Qxb6 Kxb6

Samuel Loyd found faster in 1895.

[FEN ""]
1. c4 d5 2. cxd5 Qxd5 3. Qc2 Qxg2 4. Qxc7 Qxg1 5. Qxb7 Qxh2 6. Qxb8 Qe5 7. Qxc8+ Rxc8 8. Rxh7 Qxb2 9. Rxh8 Qxa2 10. Rxg8 Qxd2+ 11. Kxd2 Rxc1 12. Rxg7 Rxb1 13. Rxf7 Rxf1 14. Rxf8+ Kxf8 15. Rxa7 Rxf2 16. Rxe7 Rxe2+ 17. Kxe2 Kxe7

https://pdb.dieschwalbe.de/search.jsp?expression=PROBID=%27P0001931%27

This is 17.0 moves.

It is also possible to do it in 16.5 moves but I can't find it yet. See François Labelle's page.


Do grandmasters ever disagree on what the main purpose of a move was? I don't mean disagreeing on which move should be played, but why the chosen move was played.  The reason why I ask is because if I study a game and read the annotater's explanation, I tend to ask myself if other grandmasters annotating the game would say the same thing or not, or perhaps agree partly but add more important explanations that were not mentioned.  Has anyone encountered this before?  The only reason why I haven't is because I've always only had one annotater to read from regarding a specific move when studying a game (I mean verbal commentary), so I don't get a chance to compare.

For example, one grandmaster says "Played to protect the weak square on e5", and then another says "The piece moves out of the way so that a2-a4 can be played and launch a minority attack.", so they are really saying different things on what the primary purpose on the move was.  Perhaps the first annotater said what he said because the minority attack (or a2-a4 even) was never actually played due to change in circumstances, while the second annotater saw that the minority attack was the original plan but it was changed shortly.  Or perhaps the second annotator was wrong about the move's primary intention (perhaps the minority attack was just a secondary possibility) and it really was meant to protect the e5-square, and that is why a2-a4 was never played.  I just made up that hypothetical example of course.  You can imagine similar "arguments" between grandmasters.

The short answer is "Yes, they most certainly do". Not only that but they often disagree on whether the move is a good move or a bad move! This kind of thing comes from players and annotators having preconceived ideas about the players whose games they are annotating rather than because they are trying to deceive possible future opponents or keep important analysis secret. Players who still have such secrets to keep rarely if ever annotate games and if they do will be mostly bland and just follow the kind of analysis you would get from a computer.

Here is a concrete example of some very explicit disagreement from John Nunn's latest book "John Nunn's Chess Course". It's worth quickly saying that it's not really a chess course. Rather it is an excuse for John Nunn to publish very detailed analyses of some of Lasker's games disguised as a chess course ;-).

  The second example is from much later in Lasker's career ...

  It shows how once a narrative is accepted, the analysis is then
  shoehorned into being consistent with it and objectivity is thrown out
  of the window. The numerous spurious improvements for Black bear
  witness to the power of the consensus and only serve to obscure the
  real point that Lasker skillfully led the game into a deceptive
  position that appeared much better for Black but was not.

  This time the references are to Why Lasker Matters by Soltis
  (Batsford, 2005) and Emanuel Lasker Games 1904 - 1940 by Soloviov
  (Chess Stars, 1998). ... This is another game which has been
  considered little more than a swindle, and it's interesting to see how
  Soltis and Soloviov jump through all sorts of analytical hoops in
  order to keep the narrative intact.

There then follows a detailed analysis of the game interspersed with criticism for Soltis and Soloviov for just getting the analysis wrong. Nunn clearly has a very high opinion of the longest reigning world champion and believes that critics have often done Lasker an injustice which he puts right.

Note that the analysis that Nunn takes issue with is relatively modern. It is not that computers weren't available in 1998 and 2005 for Soloviov and Soltis to use to check their analyses rather that they neglected to use them because they had already made up their minds!


Why was this move in a puzzle? I was on the chess.com app this morning doing the daily puzzle and it wanted me to play Re2. This is questionable to me, because it just delays the mate, but I figured I might have missed something. Then what really perplexed me is that Black then plays Qg7. It appears to me that Black is sacrificing his queen for no reason when he has a mate in 2. I don't see how White has time to mount an attack on Black or come back to defend in time. What am I missing?

[FEN "5r1k/1pQ4p/3nB1p1/3P4/5p2/1P5P/rq5P/4R1RK w - - 0 1"]

1. Re2 Qg7 2. Qxg7+ Kxg7 3. Rxa2

If black plays QxR then white plays Qc3+ with mate to follow. Black's Qg7 stops the mate. With the black queen on b2 white cannot play Qc3. The Re2 move is to divert the black queen

[FEN "5r1k/1pQ4p/3nB1p1/3P4/5p2/1P5P/rq5P/4R1RK w - - 0 1"]

1. Re2 Qxe2 2. Qc3+ Qe5 3. Qxe5+ Rf6 4. Qxf6#


How large can a rating difference become before either player realizes it's not worth engaging in a game? I think the relationship changes as rankings increase. For example, players with ratings lower than 1000 might be able to play all other players in that range and still enjoy themselves, but if a sub-1000 player matched up with a 1400+ player, the two might not enjoy themselves in the same way. At which levels do players begin to learn strategy and stop making mistakes?

One thing is, I think there may be real surprises even if the rating range is quite vast. You'll never know the real strength of an opponent most of the times (because of lack of rated games etc.,) On another perspective, lets say one of the player is 1400 Elo and the opponent is 2000 Elo, it will still result in a good "feeling" for both the players if they take it sportively. The 1400 Elo player will clearly appreciate the consistency in the 2000 Elo player's moves and will really learn a LOT. The other way round, it is a good opportunity for the 2000 Elo player to test out his skill or experimenting things which he would not dare against a player of his own caliber (Like for example sacrificing the Queen for a Knight and Bishop and trying to win in the given situation).

So I feel there is no rating difference that can make the chess game not worth engaging, if you look at the bright sides.


How did Timman decide on d5 in this position? In Gheorghiu-Timman 1982, how did Timman decide to play 34…d5? It seems like an amazing move to find.

 [FEN "2r5/p1r2b2/1p1p1k1p/PP2ppp1/2P2P2/3KP1P1/2RN3P/2R5 b - - 0 1"]

 1... d5

In this position, black clearly is better with heavy pressure down the c-file, but it is clear that c4 is also well defended, and that black cannot bring any additional pressure on c4 except with d5. So, can black do anything else like try and infiltrate with Kg6-h5? I ran some logical lines with Stockfish, but they are labyrinth-like, and while it is clear that black is still the one pushing, nothing was clear. In those lines, black also has to be on the lookout for possible e4 attempts by white, and also axb6 axb6, Ra1-a6 lines that can gain great counterplay should black win b6, and start pushing the b5 pawn.

d5 is a way to increase the advantage, and clarify the position. Timman also saw that the white knight was no match for the good bishop, and better black king position. Gheorgiu should have avoided that at all costs.

 [Event "Olympiad-24"]
 [Site "Valetta"]
 [Date "1980.11.25"]
 [Round "5"]
 [White "Gheorghiu, Florin"]
 [Black "Timman, Jan H"]
 [Result "0-1"]
 [ECO "E32"]
 [WhiteElo "2605"]
 [BlackElo "2600"]
 [PlyCount "106"]
 [EventDate "1980.11.20"]
 [EventType "team-swiss"]
 [EventRounds "14"]
 [EventCountry "MLT"]
 [WhiteTeam "Romania"]
 [BlackTeam "Netherlands"]
 [WhiteTeamCountry "ROU"]
 [BlackTeamCountry "NED"]
 [FEN ""]

 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 O-O 5. a3 Bxc3+ 6. Qxc3 b6 7. Bg5 Bb7 8. e3 d6 9. f3 Nbd7 10. Bd3 c5 11. Ne2 Rc8 12. O-O Ba6 13. b4 cxd4 14. Qxd4 h6 15. Bxf6 Qxf6 16. Qxf6 Nxf6 17. Rac1 Nd7 18. Rfd1 Ne5 19. b5 Bb7 20. f4 Nxd3 21. Rxd3 Rfd8 22. Rdc3 Rc5 23. Nd4 Rdc8 24. Nb3 R5c7 25. a4 Bd5 26. Nd2 f5 27. Kf2 Kf7 28. g3 Ke7 29. Ke2 e5 30. Kd3 Be6 31. a5 g5 32. Nb3 Kf6 33. R3c2 Bf7 34. Nd2 d5 (34... Kg6 35. axb6 axb6 36. Ra1 $11) 35. fxe5+ (35. axb6 axb6 36. Ra2 $2 dxc4+ 37. Kc3 Rc5 {And black is too fast.}) 35... Kxe5 36. cxd5 $2 {Going into the bishop versus knight ending was clearly hopeless.} (36. axb6 $1 axb6 37. c5 $1 Rxc5 (37... bxc5 38. Nf3+ Kf6 39. Kd2 Bh5 40. Nd4 Ke5 41. Nc6+ {And if black hopes to win, he will need to sacrifice the exchange here.}) 38. Rxc5 Rxc5 39. Rxc5 bxc5 40. Kc3 Kd6 41. Nb3 c4 42. Nd4 Kc5 (42... Bg6 43. Kb4) 43. Nxf5 $11 {This leads to an ending that is possibly holding, but would have been very hard to find at the board.}) 36... Rxc2 37. Rxc2 Rxc2 38. Kxc2 Kxd5 39. axb6 axb6 40. Kc3 Bh5 41. Nb3 Be8 42. Kb4 Ke4 43. Nd2+ Kxe3 44. Nc4+ Ke2 45. Nxb6 f4 46. gxf4 gxf4 47. Nd5 f3 48. Nc3+ Ke1 49. Ne4 f2 50. Nxf2 Kxf2 51. Kc5 Bd7 52. b6 Bc8 53. Kd6 h5 0-1


Is there any better play than the 3-move mate? I know how to cause a checkmate in three moves. Are there any better ones? I've been told that  there is a two move one but, I have never found someone who can do it. Is it just a legend that has happened once or twice?

There is a two-move mate: the Fool's Mate. However, it requires White to be, as the name implies, extremely foolish!

[FEN ""]
1.g4 e5 2.f3 Qh4#

As you can see, this mate relies on White advancing pawns without any regard for his King's safety. There's no way to force a two move checkmate (if there were, Chess would be an awfully boring game!).

As to whether it's ever occurred in real (master) play, I can't find any record of it, though the Wikipedia article mentions Teed vs. Delmar, 1896, where a very similar mate is delivered a few moves later.


Facing irregular or uncommon openings How do you deal with this? I'm a bit of a chess perfectionist, and I always want to play the best move, so when I go up against an irregular opening, I don't do badly, but it's hard be 100% sure you made the best move in the opening, and that really bothers me psychologically.

My current method for dealing with these types of situations is to just follow the basic opening principles, but at my level I feel like this is not detailed enough or too vague, since I always try to strive for a certain level of understanding in every position. What can I do to be more flexible in this area of chess? Are there more detailed guides for playing against uncommon openings?

Even though I don't necessarily play badly, I really want to learn to be "comfortable" in all positions. How would I achieve this? Is the answer to play beginners since they tend to play strange openings all the time? I've already done this, but I still don't seem "comfortable" enough. Maybe its all in my head?

What you describe is the best advice to meeting an unusual opening: play by the principles.

In terms of resources, there are 2 I can think of:

Beating Unusual Chess Openings by IM Richard Palliser. By 'unusual', Palliser really means anything other than 1. e4 or 1. d4, so he covers from Black's point of view:

  The respectable (English Opening, Reti and King s Indian Attack) through to the offbeat (Nimzo-Larsen Attack, Bird s Opening) and the totally bizarre (Orang-utan, Grob)

Chess.SE. We are always happy to see questions such as What are the ideas behind the Blackmar-Diemer gambit?


How do people 'see' the position in blindfolded games? How do most people play blindfolded chess? Is it akin to a live video feed in their mind where they can see all of the pieces, or do they just remember what moves have been made so far and go from there?

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.


Can someone explain the positional advantages for white? [FEN "3r1rk1/7p/bq2ppp1/p1R5/Pp2P2P/4QB2/1P3PP1/3R2K1 w - - 0 1"]

As far I can see, Black’s bishop has more scope than the white one, White has some isolated pawns, and the Black pawns rule the 5th rank.S Since Black appears to be better here, then why does the engine show a better evaluation for White much more than I expected?

You evaluate the position statically which only rarely works. As for your static evaluation you are correct, that the black bishop is stronger and that the pawns take some squares on the fifth rank. On the other hand, white has two active rooks vs one black rook.Stockfish gives a static evaluation for this position of +0.76 if white is to move and +0.5 if it is black's move. So statically it is roughly equal with a slight advantage for white.

However, such static evaluation is only really useful (if at all) in quiet and/or closed positions. In open positions like the one here, where there are concrete ideas, the static evaluation does not tell you anything. You should look at least a couple of moves deep to see what plans white and black could follow.

White has at least three obvious ideas: play against the a5 pawn, against the week pawns on e6 and f6 or directly against the black king.

Black has no obvious plan other than exchanging pieces and (if veryvery lucky enter the white position with heavy pieces.

Concretely to your question:

Black’s bishop has more scope than the white one: True, the black bishop has more scope, but there is not much to do along that diagonal.

White has some isolated pawns: Neither player has isolated pawns. Please check what an isolated pawn is.

the Black pawns rule the 5th rank.S: They cover squares on the 5th rank, but hey that's just the 5th rank, i.e., on the black side of the board (in the starting position the pawns rule the 6th rank....). Also (and much more relevant here), since the pawns are next to each other they don't support each other anymore and the pawns on e6 and f6 are weaknesses. Typically, building such horizontal line of pawns to gain space is a good thing to do in the opening phase, when the pawns can be supported by pieces. Towards the endgame such pawn lines can often become weaknesses.

Assuming it is white to move,my engine says about +3, (which means white is clearly winning) and gives the following line: 1. Rxd8 Qxd8 (or Rxd8 which is slightly worse) 2. e5

If black captures fxe5 or allows white to capture exf6, he will end up with a very weak isolated pawn on e6 (in addition to the weak pawn on a5) and a rather open king (ideas with Qe5, Rc7 or h5 look very scary for black).

If black closes the position with f5, the engine likes to go for the a5 pawn by exchanging queens with Qg5. Another viable option could be h5 with an attack on the king. In any case, black is left with weak pawns on e6 and a5.

So in summary, it is basically black's weak pawns that make the difference.

If in the initial position you...

move the pawn from f6 to f7, the evaluation improves for black to +2, because the pawn structure is much more stable.
remove all the pawns on the a and b files, the evaluation improves for black to +1 only.


Tablebases say this position is drawn, but Stockfish disagrees-What does that mean? Today I found myself in the below position as black (me to play). My gut told me it should be a draw, but as my opponent and I are both fairly weak there was a significant chance one of us would blunder, so I decided to play on just to see what would happen, and sure enough we ended up exchanging rooks and that was that
After the game, I checked this on tablebase and it's very clear that this is a drawn position. However, Lichess shows this position as -0.6 and chess.com shows it as -0.88 (I assume they use different versions of Stockfish). I'm having trouble understanding what Stockfish feels my advantage here is or what those numbers really mean. If it's a definite draw then I'd expect it to show +0.0.
Is it saying there are more ways for white to blunder than black, so that is more likely to happen? Is there some tactic or 'style' I could employ here that might increase my chances of inducing a mistake by my opponent? Am I overthinking this and should just offer a draw in this position?
[FEN "8/8/2r2k2/R4P2/4n3/1K6/8/8 b - - 0 1"]

If the tablebase says that it's a draw with optimal play from both sides, then you can always ignore whatever Stockfish or any other engine says. The tablebase knows the objective evaluation for any position with 7 pieces or less.
What Stockfish 11 (or any earlier version) does is calculate as far as it can ahead, evaluate the positions it reaches in its search, and then use those numbers to give an evaluation for the starting position (obviously a lot more is involved, but that's the basic idea). If Stockfish reaches a position where Black's still up a knight, it will usually give some evaluation in Black's favour due to how its evaluation function works. It has no way of knowing that it's certain K+R will draw against K+R+N, unless this knowledge was explicitly programmed into it. Stockfish will only say it is a draw once: it's calculated a forced repetition will happen, it sees that a K+R vs K+R is forced, or the game has reached the 50 move rule (or will imminently do so). Although if you were to hook up Stockfish with a tablebase (some people do this, such as serious correspondence players), Stockfish should always give the tablebase evaluation in positions with 7 pieces or less.
However, it's worthwhile noting that Stockfish NNUE (as well as Stockfish 12 I'd assume) gives an evaluation of equality, with the number somewhere around -0.13 for a K+R vs K+R+N endgame I set up, after not thinking for too long. In the position you have with the pawn, NNUE started giving a 0.00 evaluation once it reached around depth 20. This is probably because "it" had experience playing this K+R vs K+R+N endgame, and in all normal circumstances the result is a draw. So, NNUE's neural net evaluates this endgame appropriately as equal. Note that this is all without the use of a tablebase.


Can solving lots of mate in one (or two) problems be beneficial? I am a ~1500 player on chess.com (so I'm in the online beginner-intermediate range).

There is a book titled "Chess: 5334 Problems, Combinations and Games" by Lazlo Polgar, father of Judit, Susan and Sofia. From amazon:

  Chess analyzes more than 5,000 unique instructional situations, many taken from real matches, including 306 problems for checkmate in one move, 3,412 mates in two moves, 744 mates in three moves, 600 miniature games, 144 simple endgames, and 128 tournament game combinations.

Mate in one and two problems aren't usually too difficult to solve with experience. But my question is, does the difficulty of the problem matter? Isn't pattern recognition a crucial part of studying chess? I feel like I can get a lot more from simple mate in one (or two) problems then just solving them, and going to the next problem right away.

For example, these simple situations seem to be really beneficial, if I think about them as positions I want to achieve in real games, and if I try to analyze the position.

Or maybe I am dead wrong about this, and I should concentrate on doing problems, that are difficult to solve.

Any opinions?

There's a wide array of opinions as to the debate on whether simple problems done repetitively, or more challenging problems are better for improvement at tactics.

My personal opinion is that both have their place and both improve different essential things. Getting those simple problems down cold is very good for pattern recognition and board vision, but the more challenging problems improve tactical analysis abilities, problem solving skills, and help prepare a player for tournament situations.

As for whether your collection of thousands of mate in 1 or 2's would be very helpful, I'd say that mating patterns are certainly important to practice but I don't know if you really need to train with quite so many. It certainly wouldn't hurt, but you might have faster growth practicing with the mating problems on chesstempo. They have them tagged and you can create your own sets of problems if you're a member.


Moves to test a notation generator I've made a small program that takes a list of moves in ICCF notation and translates them to the following:

SAN
FAN
LAN
MAN
RAN
CRAN
Smith
Descriptive
Coordinate
ICCF

For example, a starting move of 2133 (Nc3 in SAN):

SAN  FAN  LAN     MAN  RAN     CRAN  Smith  Descriptive  Coord  ICCF  Comments
Nc3  ♘c3  Nb1-c3  Nc3  Nb1-c3  Nc3   b1c3   QN1N-QB3     B1-C3  2133

Unfortunately, I'm having some difficulty understanding a few of the rules of the various notation formats (especially Descriptive - as you can see, it doesn't currently omit the unambiguous ranks/files because I haven't implemented the check for unambiguous destination ranks/files yet... so it's possibly a bit too descriptive). For example, checks (e.g. +) are added to the end of a move, but promotions (e.g. Q) are also added to the end of a move. What if both happen at the same time? For that particular situation, I'm pretty sure the check is listed after the promotion indicator, but I'm even more sure that there are other situations I'm not even thinking of.

What I'm hoping for (and haven't been able to find with a few Google searches, as I don't even know what search terms would produce it if it existed) is a sample game with moves that create these uncommon notations, so that I can input them into my program as a kind of test suite, see what it produces, and check the results. Alternatively, a simple list of these situations (e.g. "a pawn that captures a piece into a promotion, for a check") would be good too.

If, once I've done that, I can't tell if the program's output is even correct, I'll ask a separate question about it.

Chessbase 6 light version, free if you can find it, has an option to view the notation in descriptive notation.
http://forums.ubi.com/showthread.php/499956-How-to-Convert-Descriptive-to-Algebraic-Forums may be a useful link.

The promotion does go before the check. There is no check before the promotion.  Some people put an "=" before the promotion.

An interesting game to try to convert would be one with multiply Queens.  This gives a promotion and ambiguity.  You should also get a game with Queenside castling.  When I test my move generator, I setup a semi-random position to test each position.  To test your output, I agree with Tony Ennis, convert it to algebraic and play through the game.  If all else fails, post them online and ask for someone to check the result.

Descriptive notation lesson:
The first character is the piece being moved, pawns are not considered a pieces except for when they are capturing.  The second character is "-" for a normal move or "x" for captures; if a Pawn captures, use the piece symbol, "PxP."  The third character is the square where it lands.  The files are named after the piece's home square.  The third character is the rank counting from the side which made the move.  "e4" is written as "P-K4" if White played the move else "P-K5."

Note:  The old style did not include a rank if it is the first.

Ambiguity is settled by an expanded description.  The first method is to try to expand the destination square.  That is if you move a Bishop to "N5", if both Bishop can reach "N5", the square is expanded to either "QN5" or "KN5."  If two pieces can reach the same square, the piece is expanded by the original side it started on.  That is if both Knights can go to "Q2," you prefix the piece with its starting side, e.g. "QN-Q2."  If a promotion occurred, you have to use long notation, "QN5-N6."

Castling was "castles" with the expanded form being "castlesQ."  In modern times, people adopt the algebraic form.


Who are the strongest non-professional GMs? As title above states, who are currently the strongest non-professional chess players? By this, I mean players who have a full-time job outside of chess. For example, I remember German GM Georg Meier mentioning in an interview in 2018 that he has a full-time job in a bank.

Up until recently, that title would have gone to Teimour Radjabov without question in my mind. Since April of 2015 until last month, he has only played 149 games. That is not many for a top-flight GM over four and a half years. That said, he just won the right to play in the Candidate's, so he may becoming more active again.

Quite a number of old GMs were musicians and engineers. GM Mark Taimanov was also famous as top concert pianist in the Soviet Union. Mikhail Botvinnik was famous for being an electrical engineer and computer scientist while also being the world champion at the same time. Dr. Ruben Fine was a Doctor of psychology. GM Helmut Pfleger of Germany is an MD.

GM Lars Bo Hansen is 2560, and is an Assistant Professor of Sport Management and Business Strategy at Florida Institute of Technology in Melbourne, Florida.

As stated by Ian Bush, Luke McShane is considered the strongest with an outside full-time job, but I am not sure I would give him the title "of strongest non-professional GM" based solely on that as he plays a fair amount, and has played 182 games in the same time frame as I listed for Radjabov. Based on that, and the 100-point difference, I still have to go with Radjabov.

Here is a cool list of chess players, who have doctorates.


Does black have an advantage if white plays 1. h4 White would playing as if they are black, but with the insertion of h4. Does this insertion give enough advantage to white to at least equalize? Does the insertion of h4 weaken white's position even more than if white skipped his first move.

Imagine a variation that there is white's Bg5 or Ng5 which should be met h6. I mean theoretical lines. And then play with black as you were white. I think that 1. h4 makes white worse than black usually is.

White has difficulties with castling short
g4 instantly weak


What is the number of legal positions in a chess game? There have been several questions regarding the possible number of chess games. for example; Database of every possible move in chess. However,can there be an estimate on the number of "allowable" chess positions?
For another example, White pawns cannot occupy the first row and Black pawns cannot occupy the eighth row. If a given chess piece is occupying a square, then another chess piece cannot occupy that. Using simple elimination rules coded, can we have an estimate on the number of unique positions that chess pieces can have since they would be reducing in number? An upper bound on positions before applying any elimination rules would be the sum of (64 C 32 + 64 C 32 ... + 64 C 2). This is less than 10^20. With elimination rules, they should be significantly lower.
Any ideas on how elimination rules are written for chess pieces?

Upper bounds on the number of allowable positions are discussed on the Shannon number  Wikipedia page.
There is an accepted upper bound of 5×10^52 by Vicor Allis, and a less verified upper bound of 2^155 (approx 10^46.7) by John Tromp.
By comparison, the number of atoms on earth is about 10^50.


Hosting bughouse server for local competition? I'm interested in running a local competition for bughouse engines. What chess server software can I use to run the games? The most relevant question I found was but the answer is almost 4 years old.
Is there an well-maintained open source chess server I can use to host a bughouse server?

As the question you linked indicates there is a way to run bughouse engine games via FICS using XBoard/Winboard, which I also explained in my answer to a related question.
However, if all of your engines are anyway running locally, that is neither very convenient nor an efficient way of running such matches, since the server communication in principle is completely unnecessary. Unfortunately, there does not seem to be any tool for engine matches similar to cutechess as there is for other chess variants.
Therefore, a few months ago I started to develop fairyfishtest as a script for testing bughouse (and many other variants) based on and for my engine Fairy-Stockfish, but it should also work with other CECP engines. It currently still has two issues with bughouse rules, but those are far from impossible to solve.
There is also a fork of python-chess that supports bughouse, but there does not seem to be any documentation on it, so I do not know whether/how it can be used for engine testing in bughouse.


Challenge: Create the longest set of moves where the game is able to be perfectly reproduced from only the current board state and move number The challenge is to create the longest list of half moves whereby an AI could re-create that list of moves perfectly, only given the ending board state and the number of moves.
As example I will first give a short example that does NOT work.
[FEN ""]

1. a3 a6 2. b3

From that final board state, it is impossible to differentiate it from  1. b3 a6 2. a3.
And a short example that DOES work.
[FEN ""]
1. a3 a6 2. a4 a5

There is no way to get this board state in exactly two moves other than what was done here.
Scoring will work like this.

+1 point per move.
+5 points if the game is complete, i.e. the last move in the sequence is checkmate.

This is my best solution so far.
[FEN ""]

1. a4 h5 2. a5 h4 3. a6 h3 4. axb7 hxg2 5. Rxa7 Rxh2 6. Rxa8 Rxh1 7. Rxb8 Rxg1 8. Rxc8 Rxf1

This would score 21 points: 1 point for each of the 16 moves plus 5 points for ending in a checkmate for black.
Note: Opening pawns moving 2 spaces instead of one is necessary in this particular solution.  A 9 turn game where the pawns each move one space per turn would be undifferentiated from an identical game where pawns open with the two space move and then rooks spend an extra turn making their first capture. Also, the game cannot be extended by slipping in Bxg2 at any point in time for White, because it would be unclear, when looking back, when such a move had occurred, since there are several possible turns for such a move to occur.

The current length record is an astounding 57.5 moves (115 half-moves).
[Title "Dmitri W. Pronkin & Andriy Frolkin, Die Schwalbe 06/1989, 1st Prize, PG in 57.5"]
[FEN ""]

1. a4 h5 2. a5 h4 3. a6 h3 4. axb7 hxg2 5. h4 d5 6. h5 d4 7. h6 d3 8. h7 dxc2 9. d4 a5 10. Bh6 c1=R 11. e4 Rc5 12. Ne2 Rh5 13. e5 c5 14. e6 Nc6 15. b8=R a4 16. Rb4 a3 17. Ra4 c4 18. b4 c3 19. b5 c2 20. b6 c1=R 21. b7 Rc4 22. b8=R Qa5+ 23. Rbb4 Bb7 24. Nbc3 O-O-O 25. exf7 e5 26. Rc1 Bc5 27. f8=R a2 28. Rf3 a1=R 29. Na2 g1=R 30. Rfa3 Rg6 31. f4 Re6 32. f5 g5 33. f6 g4 34. f7 g3 35. f8=R g2 36. Rf5 g1=R 37. Bf8 Rg7 38. Ng3 e4 39. Bd3 e3 40. O-O e2 41. Rcc3 e1=R 42. Bc2 R1e3 43. d5 Rdd7 44. d6 Rdf7 45. d7+ Kb8 46. Qd6+ Ka8 47. Qc7 Nge7 48. d8=R+ Nc8 49. Rdd3 Rhg8 50. h8=R Rae1 51. Rh6 R1e2 52. R1f2 Rce4 53. Kf1 Bd4 54. Rfc5 Ne5 55. Nf5 Nc4 56. Nd6 Nb2 57. Rbc4 Nb6 58. Qb8+

This length record was reportedly beaten in 2017 by Pronkin, Frolkin and Keym (to 58.5 moves) but unfortunately it turned that the longer problem had more than one solution. I do not know if the authors managed to make the problem sound.
Although this problem is not computer-checked, it has withstood human testing for 41 years, so it might as well be considered computer checked by the greatest computer of them all-the human mind.


How to learn e4 e5 as black? I'm about 1800 FIDE and I wanted to incorporate e4 e5 to my repertoire as black, however, as soon as i started studying it, it became clear to me that its one of the most complex openings to prepare.

So can you guide me to the right approach in learning this opening? What are the best resources? Where can i learn the ideas instead of just memorizing lines? Do you have an tips regarding this opening? And who are the best practitioners or e4 e5?

much appreciated!

There are a lot of good resources on 1. e4 e5 lines.  I would recommend you combine some study of an up-to-date theoretical work (Bologan's two books, Black Weapons, and Bologan's Ruy Lopez are very good, and all you would need for a long time) with going through some games.  For example, if you want to get a good feel for where your pieces belong and typical maneuvering in closed Ruy Lopez positions, going through Karpov's games as Black in these lines can teach you a lot.

Ultimately, you are going to have to memorize some sharp lines.  Many of the gambits played in the Romantic era in chess come after 1.e4 e5, and it is simply not possible to play these positions correctly without learning some theory.  The good news is that Black usually has a number of sound options against White's sharper tries.

The big advantage of 1.e4 e5 over all other defenses to 1.e4 is that once you learn the various gambits and deviations (Scotch, Vienna, Ponziani, etc.), you have a choice among a large number of completely sound Ruy Lopez systems with Black, all of which are eminently playable, many of which are quite different from each other, and all of which give you chances to play for a win.  This is why many of the top players use 1...e5 as their main defense to 1.e4.  It is a great opening to choose for the long term, because if you get bored with one Ruy Lopez system you can just learn another.


Should an arbiter claim draw at a K+R vs K+R endgame? I was asked for first time to help at a non federated tournament for kids to arbitrate their games, played at 30 minutes with no increment time.
It was a scholar tournament and they made mistakes as leaving checkmates in one, let the queen to be captured etc.

At one game both kids arrived to a K+R K+R endgame. There was not a way to quickly gain the rook and win the game and both kids had time.
One kid claimed it was a draw. We were two arbiters (not experts, just two 1900 helping a bit at the club).
We claimed draw.

Was it a correct decision or we should have left the kids play?

You can declare a draw and in fact you are required to declare a draw but only after you have counted 75 moves by each side without a capture or a pawn move. This is according to the FIDE Laws of Chess article 9.6.2:

  9.6 If one or both of the following occur(s) then the game is drawn:

  9.6.1 the same position has appeared, as in 9.2.2 at least five times.

  9.6.2 any series of at least 75 moves have been made by each player without the movement of any pawn and without any capture. If the last
  move resulted in checkmate, that shall take precedence

Of course the players are also free to agree a draw between them.

EDIT: blues makes the following comment:

  III.5.1 may also apply. If the arbiter agrees that the opponent cannot
  win by normal means, or that the opponent has been making no effort to
  win the game by normal means, he shall declare the game drawn.
  Otherwise he shall postpone his decision or reject the claim. This
  does not require 75 moves or fivefold repetition

I will answer that here since there is insufficient room in a comment to do so.

Guidelines III.5.1 almost certainly does not apply in this case. III.5.1 is not standalone. It is part of section III and is dependent on earlier parts of III.

Let's take a look.

  Guidelines III. Games without increment including Quickplay Finishes

  III.1 A ‘quickplay finish’ is the phase of a game when all the remaining moves must be completed in a finite time.

  III.2.1 The Guidelines below concerning the final period of the game including Quickplay Finishes, shall only be used at an event if their
  use has been announced beforehand.

  III.2.2 These Guidelines shall apply only to standard chess and rapid chess games without increment and not to blitz games.

First, according to the OP, the time control was all moves in 30 minutes, so a rapid time control and no increments mean it is possible that III applies. However according to III.2.1 these shall only be used at an event if their use has been announced beforehand. They were almost certainly not announced beforehand, else the two arbiters would have at least know of their existence and they appear not to.

Suppose they were announced beforehand. Then we come to:

  III.4 If the player having the move has less than two minutes left on
  his clock, he may request that an increment extra five seconds be
  introduced for both players. This constitutes the offer of a draw. If
  the offer refused, and the arbiter agrees to the request, the clocks
  shall then be set with the extra time; the opponent shall be awarded
  two extra minutes and the game shall continue.

The OP in one of his comments seems to say that both players still had 25 minutes left. This would mean this does not apply. Nevertheless supposing the player did have less than 2 minutes left, the arbiters cannot apply this rule unless the player specifically asks for it. The arbiters are not allowed to help the players in any way and may not volunteer this information during the game. They may only make announcements informing all players before the game.

Continuing, we finally reach the part blues references:

  III.5 If Article III.4 does not apply and the player having the move has less than two minutes left on his clock, he may claim a draw
  before his flag falls. He shall summon the arbiter and may stop the
  chessclock (see Article 6.12.2). He may claim on the basis that his
  opponent cannot win by normal means, and/or that his opponent has been
  making no effort to win by normal means

First, this can only apply if III.4 does not apply. The only way that can happen is if there are no digital clocks capable of being set with the required time and increment. If such clocks are available then III.4 applies and III.5 does not apply.

Suppose, however, that all the previous counterfactual "if onlys" apply then III.5 can only apply if the player also knows the rule and makes the specific request in the correct manner. Again, even if the arbiter knows the rule he may not help the player by volunteering the information.

Hence my original conclusion that - Guidelines III.5.1 almost certainly does not apply in this case.


Comprehensive list of ECO codes together with the list of moves I am looking for a comprehensive list of ECO codes with various variations together with a corresponding list of moves. Basically something like:

B01 Scandinavian (centre counter) defence 1. e4 d5
B01 Scandinavian defence, Lasker variation 1. e4 d5 2. exd5 Qxd5 3. Nc3 Qa5 4. d4 Nf6 5. Nf3 Bg4 6. h3
B01 Scandinavian defence 1. e4 d5 2. exd5 Qxd5 3. Nc3 Qa5 4. d4 Nf6 5. Nf3 Bf5

The best I was able to find is this resourse, but it is kind of bad, because all they can give me about Sicilian is this:

B20-B99 Sicilian defence1. e4 c5


Ranking systems that take into account the size of the victory I run competitions, not in chess, but my question relates to chess Ranking systems, and will give an example of the issue I face. Game 1:

Alice scores 5, Bob 4, Chris 3.

I use the glicko-2 and elo Ranking system to break that down into two wins for Alice (over each other player) and one win for Bob (over Chris).

My problem is that if the result was:

Alice 10, Bob 4, Chris 3

That is a much bigger win for Alice, but the ranking system sees the result as no different from the first.

Has anyone come across a ranking system that takes into account margins of victory etc.?

If you're interested in use (more than in development), you should give a try to rankade, our ranking system that features rankings, stats, and more.

Rankade doesn't use Elo, but its algorithm (called ree algorithm), although more complex, is similar to Elo if you play 1-on-1 matches only.

Opposite to Elo and Glicko  (here's a comparison), rankade can manage any kind of match (one-on-one, faction vs. faction (two teams, which may be asymmetrical),
multiplayer, multi-faction, cooperative games, single player games, and so on), so you can insert one match with Alice 5, Bob 4, Chris 3 output (without breaking down one actual match in multiple fake matches). Anyway, rankade - like all aforementioned ranking systems - does not incorporate margin of victory (even if you can easily manage this issue using weight feature, and/or insert scores for stats).


Are there any (free) games databases out there? I am searching for a broad and extensive games database (i.e. games played between real players.)

I can hardly seem to find any (even paid ones.) - However all sorts of chess software has these built in.

Where can I get my hands on one?

I will use it for a lot of analyses on different players, openings etc.

Hope someone can help me out!

There is a pretty big one if you are willing to spend some 40 euro.

This (Million Base 2.2) is the biggest free database I know of.


Is it legal to move a piece if your opponent has not hit the clock? I have played some rapid and blitz games in my city,
it was not a tournament, but a friendly match, but there's
something that bother me almost always that I've played:

I move my piece and as my hand is still in the air moving
towards the clock, and even I have not hit it yet,
my opponent has already moved a piece. Is it legal?

Yes, it is.

Let's take a closer look: Article 1.1 of the FIDE rules states:

  A player is said to ‘have the move’ when his opponent’s move has been
  ‘made’.

Article 4 clarifies how a move is supposed to be made. Specifically:

  When, as a legal move or part of a legal move, a piece has been
  released on a square, it cannot be moved to another square on this
  move.

At that point a move has been "made".

Note, however, the provision in article 6.2:

  A player must be allowed to stop his clock after making his move, even
  after the opponent has made his next move.

Even if your opponent already moved, you still have the right to press your clock.


What is the native Mac Chess app's rating? Is there a good alternative? I can't find anywhere what the rating of the Mac's native Chess app is at each level.

Is there a Chess app for Mac that shows the strength bar during the game?

The Mac Chess app engine is the Sjeng engine.

On the old Sjeng website (because Apple Chess is using the old Sjeng) is says:

  For standard chess, Sjeng's rating is probably about 2450 ELO

And I'm assuming that is at its best.

As for looking at each level, there isn't much of a way to know because, beyond the 3 moves ahead area, it starts counting in seconds, and in that realm it depends on the power of the computer. The more powerful the computer, the better it plays because it can look more moves ahead in that time.

TLDR - An estimated 2450 at it's best. It's not a very powerful engine, but it can still whoop most players on it's hardest difficulty.


Sicilian Defense: Smith-Morra Accepted, Scheveningen Formation, 7.O-O [fen "r1bqk1nr/pp2bppp/2npp3/8/2B1P3/2N1BN2/PP3PPP/R2Q1RK1 b kq - 3 8"]

What could be the best possible response to 8. Be3 for black? Would it be pushing the e pawn by a square, or developing the knight to f6?

What are the best possibilities in this continuation?

I wouldn't go for 8...e5 in this position. When black plays e5 in Scheveningen/Najdorf and even in Smith-Morra gambit, it is usually connected with a win of tempo (attacking the knight on d4) or black is forced to do so because white is threatening e5. This simply isn't the case in the position above, as 9. e5 won't do much harm.

Finally, the 8...e5 move can cause you a lot of trouble because of the weak d5 square and the a2-g8 diagonal. Therefore, I would suggest you leaving e5 for future.

8...Nf6 is a much more logical developing move and I would play it. Not surprisingly, it stands as the move #1 in my database with a great statistic (72.1% for black). For example:

[fen "r1bqk1nr/pp2bppp/2npp3/8/2B1P3/2N1BN2/PP3PPP/R2Q1RK1 b kq - 3 8"]

8...Nf6 9.Qe2 O-O 10.Rfd1 {and only then (when white threatens e5) play 10...e5 yourself} 10...e5

Another try for black is 8...a6 (covering the b5 square), but I think there will be enough time for that after finishing the development (if needed at all).

EDIT: As @Evargalo noted in the comments, in the 8...Nf6 line I gave above, you can also try 9...Ng4 with the idea of blocking the e5 break by putting a knight on e5:

[fen "r1bqk2r/pp2bppp/2nppn2/8/2B1P3/2N1BN2/PP2QPPP/R4RK1 b kq - 4 9"]

9...Ng4 10.Bf4 Nge5

The key idea of the manoeuvre is that black doesn't mind doubled pawns on the e-file, because he is pawn up and thanks to those pawns he can control the central squares d4 and d5.

Other possibilities shown by @Evargalo are to deviate from standard set-ups in Smith-Morra gambit by playing 10...Qa5 or 10...Bd7, I guess they are at least as good as 10...e5 so thanks to Evargalo for pointing them out.


Joining a FIDE tournament abroad without a rating I am an unrated USCF member, ~1800 @ lichess.org. I've been travelling from place to place for years, and was thinking about joining FIDE rated tournaments to adjust to OTB and become rated. But, if I look at the tournament's requirements, I notice that tournaments consistently need players from abroad to have a FIDE ID before entering. i.e. for the Dubrovnik Open; "Svi zainteresirani šahisti iz zemlje i inozemstva s FIDE ID brojem."

Is there any way around this(such as getting an ID without a rating), or is someone in this situation barred from tournaments until they settle down?

Often tournaments have a B- (or C-) open in which even unrated players can take part.

But I have also encountered the regulation that unrated players need to provide an estimate of their playing strength, given by their federation, to take part in an open. Maybe that would be an option for you.

Apart from reading tournament regulations carefully you can always just write to the organisers explaining your situation. They should usually be quite accommodating, and if they aren't maybe this shouldn't be the tournament of your choice anyway.


Kasparov trying to poison Kamsky Did the mature Gata Kamsky ever try to explain the accusations against Kasparov in the early 1990s about Kasparov trying to poison him? I remember at least a couple interviews in New in Chess magazine where the accusations were made.

I do not know for sure, but my guess is that those accusations largely came from Kamsky's father, who was quite belligerent at the time.  In later intereviews, Kamsky tended to avoid discussing his father and that period in his career, so I doubt it has been revisited.


Losing to low rated players I’ve been having this problem for a while and every answer on the Internet I see is "Oh just dont be too confident.” But that’s not the issue I have as I try my hardest in all my chess games. I’m rated 1600 on average. Lately I’ve been swinging to 1660 as I practice every day. I regularly crush 1300-1500 players and find my favorite games are against those in the 1600 range because I feel it’s the most even of a match for me.

However, when I play on chess.com (I have an account there from when I first started playing) I’m playing 800-900 rated players, and I easily have a 30% win rate. I cannot even begin to understand why the play I see from scholastic rated players trumps that of 1600 rated players without a single doubt.

This must have some kind of outside source, as when I play OTB chess with actual players who are most likely around 800-900 I have no problem beating them and enjoy sharing with them the good/bad moves of the game we played.

Pardon the salt, I know losing is part of the game but it feels pretty awful to work really hard and get good at chess just to be consistently beaten by beginners.

Well, if your statistics are accurate (and not just based off games you remember), then there are a few possibilities:

1) The 1300-1500 players you play in OTB in your area are overrated. Or

2) The 800-900 players online are underrated.

Also, if you think you're good at chess but are beaten by these players online, are they really beginners? Online ratings especially at a low level aren't always representative of playing strength.


Do strong players move their pieces with different relative frequencies than weak players? This question is an offshoot of Ramon Snir's earlier one about how often different types of pieces get moved, on average, in a game of chess. My question:

  Do the relative numbers of moves for the given types of pieces differ when one looks at the games of stronger players as opposed to the games of weaker players? (For example, maybe the weaker players tend to make more pawn moves at the expense of piece moves, or they make too many queen moves. I don't know.)

I was able to give an answer to the earlier question using raw data that had been extracted from a large database by someone else. That data came from a sample of 4M+ games, ranging from grandmaster play down to weak amateur play, and the aggregate numbers for move totals that are given there don't discriminate on the basis of player strength. Answering my question will require getting separate data for games between strong players and games between weak players, and I am looking for answers backed up by data rather than anecdotes.

Here's a more specific form of my question:

  Is there some Elo rating threshold N such that, when one looks at the average numbers of moves in a game broken down by type of piece, there's a significant difference between what one finds in games featuring players above N, and what one finds in games featuring players below N.

It would be interesting if more of this sort of thing could be found too, i.e. concrete differences between stronger and weaker players that can be detected by data mining. Such findings could point to specific behaviors that hold players back, or conversely ones that propel them forward. Now, maybe there aren't any such differences to be found just by looking at this kind of data, but I'd be interested to know that too.

Here is a quick an dirty analysis based on the "Million Base" PGN database.  I did this in a bit of a rush, so there may well be errors in my programming or logic.  Please don't use it for anything too serious.  Update - Note: Actually, I've just noticed I made a mistake with the data set, and limited it to the first 1 million records.  I'll post an update when I get some free time to run it again on the full thing.  In the meantime, these numbers should be interesting, nevertheless.

Obtaining the data:

I obtained the Million Base 1.74 file from this URL, since the top-5000.nl site seems to 404 when you actually try to download it.  The file contains just over 1 million games in PGN export format (that is to say, easy to parse).

Unfortunately, more than 60% of the games lacked any rating information (I was looking for "WhiteELO" and "BlackELO" tags), and even fewer had ratings for both players.  In the end, I decided to get as large a sample size as I could, and counted a player's moves if his or her rating was known, regardless of the other player's rating.

Process:

The games were parsed one by one, and if a player's rating was known, all of their moves for that game would be added to the aggregate for the player's rating group.  I chose to divide the ratings into groups of 100, so e.g. 1600 to 1699 was a single group.

Since the actual movetext in PGN is SAN, I used the following shortcut to count the moves:  Knight (N), Bishop (B), Rook (R), Queen (Q) and King (K) moves all begin with their piece's letter.  Castling (O-O and O-O-O) was counted separately, as a special case.  All remaining moves were counted as pawn moves without further examination.

No data cleanup was done.  There was no attempt to identify outliers and remove them (e.g. exceedingly short and long games, etc).  I kept, but did not include in the following analysis, the results from ratings below 1600 - the sample size for these games was well below 100, leading to large variations in results.  The raw data is provided at the end of this post.

Some shortcomings of the information:  at the moment, I've only collected very basic totals, and provided averages.  I am pretty sure that in general, the data is NOT normally distributed, but won't be able to say more without actually outputting the raw counts and running them through a statistical program.  I may do so, if there's interest.  For the moment, this means no confidence intervals, or other information about the distribution of the numbers that those averages represent.  I also haven't checked how many years the data set spans - if it represents many years, it may be beneficial to attempt to correct for the overall strength of the field.

Some Trends:

A word on player ratings - the most frequent rating groups encountered were, in order:  2400 to 2500, 2500 to 2600, and 2300 to 2400.  These rating groups provided 72% of the games counted.

Looking at the actual results, average game length was a bit of a surprise:

The sub-2000 rating groups all had significantly shorter games than the higher groups.  This may well be explained by the possibility that they were playing stronger opponents (see the average rating, above), and that they were defeated in fewer moves.  This seems to go against the slightly shorter games played by the top rating group, although that may be contributed to a smaller sample size.

The relatively large differences in average game length meant that providing the frequency of moving a certain piece, rather than the total number of times a piece is moved, is perhaps the more fair comparison.  Calculating the frequencies results in the following graph:

The following trends seem to be present:

The frequency of knight moves seems to trend slightly downwards with rating.
Bishop moves trend downwards until about 2000, then slowly trend upwards.
Rook moves trend sharply upward at roughly the same point, and stay more frequent than Bishop moves in high-level play.
Pawn moves seem to trend slightly downwards with increased rating.  A large exception is the top category, 2800 to 2900.  This brings us to the next point:
The top rating category provides outliers or counter-trends in quite a number of measurements.  This may be explained in a variety of ways - 1) the sample size is fairly low at 363, not tiny, but 10% of the next smallest sample size included.  2) Since they are at the top of the ratings groups, they never play "stronger" opponents than themselves.  3) Or simply at this level, their play style has transcended the levels below them.  My guess would be a combination of 1) and 2).
The differences in queen moves and castling moves is very small without any real trends, other than a tiny trend downwards in both cases.
The frequency of king moves has some of the largest differences.  No clear trend is visible, and it seems to change direction 3 or 4 times.

Further Analysis

Some ideas for future analysis:

Basic statistical fixes:  I feel that extremely short and long games should probably be excluded.  Also, the distribution of the actual counts might be very telling.
Splitting the analysis further up may also yield interesting results.  For example, I would be interested to know how the frequencies for black and white match up (Are they the same, or different?  Why?).
Categorisation by difference in rating might also be interesting, do players playing a much stronger opponent (say, 200 ratings above them) play with different move frequencies?  Unfortunately this requires both players' ELO to be known, which is rare in this data set.
Tendency to short vs. long-castle might also vary by rating.
Piece promotion statistics, some light structural analysis (e.g. incidence of doubled pawns, en passant, pins, forks, shown by rating) might be insightful.
"Heat-maps" of piece placement on the actual board, shown by rating might also be quite intersting.

Aggregate data in CSV format

For those who want to play with the data, feel free.

Rating Range,Sample Size,Average Game Length,Average Pawn Moves,Average Knight Moves,Average Bishop Moves,Average Rook Moves,Average Queen Moves,Average King Moves,Average Castling

1100 to 1200,4,28.500,7.000,4.000,4.000,6.500,3.750,2.750,0.500
1300 to 1400,16,34.125,9.250,6.813,5.000,4.438,4.563,3.188,0.875
1400 to 1500,35,33.800,9.400,6.114,5.514,4.514,4.057,3.400,0.800
1500 to 1600,61,33.607,8.705,7.459,4.984,4.443,4.033,3.148,0.836
1600 to 1700,163,33.153,9.227,6.485,5.110,4.699,3.969,2.816,0.847
1700 to 1800,301,31.811,8.894,6.223,5.402,4.468,3.734,2.296,0.794
1800 to 1900,307,34.251,9.537,6.642,5.577,4.889,4.039,2.759,0.808
1900 to 2000,450,35.551,9.731,6.778,5.451,5.444,4.442,2.871,0.833
2000 to 2100,3958,38.731,10.302,7.095,6.072,6.242,4.668,3.481,0.871
2100 to 2200,11217,38.905,10.501,7.116,6.086,6.245,4.629,3.445,0.884
2200 to 2300,50848,39.446,10.595,7.167,6.174,6.420,4.717,3.484,0.889
2300 to 2400,79322,39.248,10.551,7.141,6.141,6.469,4.653,3.402,0.891
2400 to 2500,111867,38.394,10.398,7.013,6.086,6.294,4.542,3.168,0.893
2500 to 2600,92225,38.308,10.396,6.972,6.082,6.344,4.515,3.104,0.896
2600 to 2700,33193,39.340,10.565,7.061,6.295,6.579,4.630,3.318,0.891
2700 to 2800,4805,40.938,10.945,7.221,6.725,6.930,4.726,3.494,0.895
2800 to 2900,363,38.865,11.311,6.879,6.284,6.160,4.391,2.983,0.857


How to find training games? My coach wants me to play 100 slow games per year (slow: G/60 or slower) against USCF 2000-2100 opposition (roughly 1930-2030 FIDE).

I just played in the U2100 North American Open last week, which was good for 7 games, but traveling and paying high entry fees is a tough way to get games.  Playing slow games online is difficult because no one wants to sit for 5 hours online, not to mention the chances of running into cheaters.

Finally, I live in Boulder CO which is a pretty dead chess scene, so finding live opposition is quite difficult.

What is the "best" way to find training partners, either live or via video Skype (to forestall cheating and give a "live" feeling) in the proper rating range?  It doesn't seem USCF publishes email lists of players, so it's difficult to reach out to their members.

There is an online chess league, All Nations Chess League, pretty much the same as a regular chess league, but online. I used to play there 7 years ago, at the time they were playing league matches on playchess.com, probably the same today too. ANCL community was quite respected in playchess.com.

And about cheat: They are investigating games upon complaint, there are statistical techniques to reveal cheaters. But it rarely happens in ANCL. All the players there are real chess fans, they simply don't play for cheating. After all, who would like to spend tons of time playing chess to cheat? It's not like cheating in a blitz game, a cheater wouldn't devote that much time to chess.

I recommend you to play there.


Question on FEN and castling I was reading about FEN notation, and noticed the following line in the relevant Wikipedia article:

  If neither side can castle, this is "-". Otherwise, this has one or more letters: "K" (White can castle kingside), "Q" (White can castle queenside), "k" (Black can castle kingside), and/or "q" (Black can castle queenside).

Why do we need to mark the ability to castle each side separately?  I can't imagine a circumstance where one would be able to castle kingside, but not queenside unless the reason you can't do one is because it would be illegal to castle in one of the directions.  But if this is the only reason, why would this need to be documented when recording a game in FEN?  Maybe there is something about castling I'm misunderstanding.

If one of the rooks has moved from its starting position, it is no longer legal to castle with that rook.

For example, if white plays 1. a4 2. Ra3 3. Ra1, white can no longer castle long, even though the king and rook are both in their normal positions.

For this reason, the FEN string must encode whether or not castling is legal (because both king and rook can be on the proper squares, but castling can still be illegal).


Do grandmasters practice blindfold chess or does it come naturally with practice? Since grandmasters are good at calculation, do they practice blindfold for improving calculations, or does it come naturally over time by solving a lot of  complex calculations?

Your question is quite interesting. If you are new to blindfold, I think this thread will help you: Can playing blindfold chess be learned or is it a natural skill?
Now, back to your query. I have discussed this topic with a GM, who is one year senior at my college. According to him, playing blindfold is "NOT impossible", but it's fairly difficult. As they participate in lots of classical tournaments where they have to write the scoresheet by hand, it is easy for them to quickly visualize the board. Also, their training process helps them to calculate from certain positions without playing the moves. But, on the other hand, it is fairly difficult to keep up every possible move, visualize every possible position and that needs intense focus and concentration. But, since they are calculating and visualizing chess more often than normal people, it is comparatively easy for them to play blindfold chess after practising for some time.
In a nutshell: it doesn't come naturally over time without practice, even if you are a GM.


How did the Fried Liver Attack get its name? Many chess openings get their name from a player who invented it and/or played it and/or documented it. Place names are also frequently used, denoting where an opening was first played or became prominent, or perhaps where players who used it were from. Other openings may take their name from some sort of description of style or some other feature of the opening.

The Fried Liver Attack doesn't seem to follow any of these patterns. Where does the name come from?

From the Wikipedia article on the Fried Liver,

  Italian way of cooking liver ("Fegatello" means to put the liver in a
  net and cook it over a fire, or, in modern times, in a pan. Here we
  can see a metaphor for what happens to Black’s king in this line: it
  is cooked like a "fegatello". Usually Black’s king is caught in the
  mating net and White increases the heat move by move – "dead as a
  piece of liver".)


What is Indian Castling exactly? Western castling doesn’t exist in historical Indian Chess (Chaturanga). Instead, in some versions, there is a cool move whereby each king can once in the game make a knight's move.
I read that it is can’t be used after check. But is that correct? Is it indeed a right which is lost for good after being checked, or is it something which cannot be exercised while the king is in check, but the right will return after the check no longer applies?
I guess I am hoping that it can be exercised even when in check, because it’s so cool to have a chance to escape otherwise certain loss - like James Bond.
How do the two kings interact directly? Must they avoid being a knight move apart. And if one has used its ability can the the other check it allowing bare K to checkmate e.g. K+N?
And how universal in Indian chess is this rule, please?
EDIT: The reason for this is that I think that Chaturanga can be interesting for chess problems, particularly retrograde analysis, but we need to agree a standard "canonical" version of the rules. The get-out-of-jail-free card is a unique mechanism like nothing else in chess, but I can't find a clear definition of how anyone uses it.
EDIT 2: Some relevant links:

https://en.wikipedia.org/wiki/Indian_chess
https://en.wikipedia.org/wiki/History_of_chess#Origin
https://www.chessvariants.com/historic.dir/hindustani.html
https://www.chessvariants.com/historic.dir/chaturanga.html

The last link given is the most relevant, see John Gollon's account. However, I submit that the text is not clear, and I'm looking for another primary source.

I was reading through "American Chess Magazine Volume 1" on Google Books, which is from 1897. There is an old article on the origins of chess therein, with the basic summary of how the game to be: it's reminiscent of today's Wikipedia as it was at the time. To my surprise, on page 264, there was direct mention of what you speak of! It occurs when speaking of chess's predecessor, Shatranj, which itself is a form of the much older, four-player game Chaturanga, aka "Indian Chess."
Here is the relevant text.

The King was limited Shatranj, as in our game, to a move of one square in any direction, except that once during a game he was allowed the move of a Knight ; i.e, from his own square to King's Knight's second square, to King's Bishop, third square, to Queen's third square, or to Queen's Bishop's second square. This Knight move was omitted and Castling substituted.

At the end of page 265, it says:

In all variations of Chaturanga, the common origin is shown by the retention of one object, viz.: the capture of the opponent's King. When this is accomplished it is a checkmate, "Shiek-Mate," the death of the King--the game is finished.

So there is a primary source, I suppose. It seems to me that the special knight move can only be used by an unmoved king. Also , reading into it, that an opponent can walk their king into a king's knight move range. Shatranj is a variation of Chaturanga, I think, and if the goal is to capture the king. So "stalemate" as we know it doesn't exist, and therefore so doesn't check. I admit that this interpretation of the check is my opinion, so it is still unclear, but what is clear is where on the board "Indian Castling" can take place.


Is 9...Nxe5 recommended in this line of the Short Variation of the Advance Caro-Kann? This question relates to the following possible continuation of the Short Variation of the Advance Caro-Kann:

[fen ""]
1.e4 c6 2.d4 d5 3.e5 Bf5 4.Nf3 e6 5.Be2 c5 6.O-O Nc6 7.c3 Bg6 8.a3 cxd4 9.Nxd4

This arose in an opening video by an Indian GM, and he said 9.Nxd4 was a poor move because white's f4 and g4 push lose its venom.  I was wondering if it simply drops a pawn.

Question: Is 9...Nxe5 recommended here?

Stockfish recommends it, but that's different to being practically playable by humans.  Stockfish plays:

[fen ""]
1.e4 c6 2.d4 d5 3.e5 Bf5 4.Nf3 e6 5.Be2 c5 6.O-O Nc6 7.c3 Bg6 8.a3 cxd4 9.Nxd4 Nxe5 10.Bf4 Bd6 (10...Nc6 11.Qa4 Qd7 12.Bb5 Rc8 13.c4 Nf6 14.Nc3 a6) (10...Nd7 11.Nb5 e5 12.Qxd5 exf4 13.Qxb7 Rc8 14.Re1 Bc5 15. b4 Ne7 16.bxc5 Nxc5 17.Qxa7 O-O) 11.Bb5+ Kf8 12.Re1 Nc4 13.Bxd6 Nxd6

Some of these lines are sharp, and may not be easily playable by humans.  Perhaps there's a reasonable alternative here.

I think when Stockfish is saying +1 for black you kind of have to go for it - yes white gets a flurry of initiative but you can't avoid mess in every game. It's hard for humans to play messy positions but it will be hard for your opponent too.