Attacking play in chess How do I play in an attacking manner? I know it sounds silly, but whenever I play, I am usually on the defensive. My opponents attack, forcing me into a corner, and usually won. The few times I attack, the opponent easily rebuffs my attacks, since I often lose control of the situation trying to attack.
Plus, attacking moves do not come obviously to my mind. I find that my opponents usually move in a different manner than I expect them to.
In short, I'm usually good at tactics, but rather less so at strategy.
I'd like some advice.
                    I played black. The game was over in two hours. I would like anyone's opinion on my game.

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

1. e4 e5 2. Nf3 Nc6 3. d4 d6 4. dxe5 dxe5 5. Nc3 Qxd1+ 6. Nxd1 Be6 7. a3 O-O-O 8. Ng5 Rd7 9. Bb5 a6 10. Nxe6 fxe6 11. Bc4 Nd4 12. Ne3 b5 13. Bb3 Nxb3 14. cxb3 Nf6 15. f3 Rd3 16. b4 c5 17. Bd2 cxb4 18. axb4 Bxb4 19. Bxb4 Rxe3+ 20. Kf2 Rb3 21. Bc3 b4 22. Bxe5 Rf8 23. Rxa6 Ng4+ 24. Kg3 Kb7 25. Rxe6 Nxe5 26. Rxe5 Rxb2 27. Re7+ Kb6 28. Rxg7 b3 29. e5 Re2 30. Rb1 b2 31. e6 Re8 32. e7 Rb8 33. Rf7 Ka5 34. Rf8 Rb3 35. e8=Q Rxe8 36. Rxe8 Kb4 37. Rb8+ Kc3 38. Rxb3+ Kxb3 39. f4 Kc2 40. Rxb2+ Kxb2 41. f5 Kc3 42. f6 Kd4 43. f7 Ke5 44. f8=Q Ke6 45. Kf4 Kd5 46. Qe8 Kd6 47. Ke4 Kc5 48. Qd8 Kc4 49. Qd4+ Kb5 50. Kd5 Ka5 51. Kc5 Ka6 52. Qb4 Ka7 53. Kc6 Ka8 54. Qb7# 1-0

My analysis:
1-5: Started off as the Italian game, though this variation is a bit unusual for me.
5... Qxd1 To throw him off balance, hopefully.
6-8: To castle early, bishop placement intended to be safe.
9... a6 Taken from Morphy defense.
10..... General move
11... Nd4 Planning for a fork on King and Rook.
12... b5 Driving away the bishop.
13...Nxb3 I prefer to exchange a Knight for a bishop.
14... Nf6 General development.
15... Rd3 in the futile hope of a pawn win.
16-19: Thought I had a fair exchange.
20... Rb3 Threatening to take away the bishop.
21... b4 felt I had the momentum, wanted to press forwards.
22... Rf8 Defending my knight.
23... Ng4+ Thought I had a brilliant fork.
24...Kb6 To Avoid being skewered by 25. Ra8+
25... Nxe5 At least I had an even exchange.
26... Rxb2 Planning for pawn promotion.
27... Kb6 Wanted my king to be in the middle of the action, not limited to last rank.
28... b3 Furthering pawn promotion
29...Re2 To attack his pawn moving ahead.
30... b2. To save my pawn, and also restrict the movement of the rook on front of me.
31... Re8. To doubly attack his pawn.
32...Rb8 Wanted to support my almost promoted pawn. I had vague plans of bringing my other Rook onto the first rank, let his rook capture mine, and promote my pawn by taking his room.
33... Ka5 Hoping to connect my rooks and also move my king ahead.
34... Rb3 Continuation of my promoting plans. Failed to notice his promoting plans! Got reckless, I guess.

35 onward: Doing my best to delay defeat.

I wonder how he held off my promotion attempts with just one rook, and got his promotion done using the other. Two of my rooks could do nothing

"In short, I'm usually good at tactics" - most of what you wrote up to that point kind of does contradict that: Your attacks are easily rebuffed, you cannot easily find attacking moves, and you fail to correctly predict your opponent's answers.

You have to understand that strategy and tactics go hand in hand. Good strategy uses tactical threats to force your opponent to make trade-offs, and good tactics are almost always prepared by strategically placing the pieces in supportive positions.

My guess is that what you were trying to say is that you are good at solving tactical puzzles where someone else already placed the pieces for you and you just have to find the mate in two or three. Now the question is how to get there, right? For this, try to expand the scope of the puzzles, e.g. try to find mates in 4 or 5, or try tactical problems where the goal is not to mate, but just to win a piece or even just a pawn. And do a lot of these puzzles, the more the better. To improve at "attacking play" you MUST practice how these attacks actually play out. Chess skill is mostly about learning and applying patterns.

Maybe counterintuitively, deepening your tactical understanding will improve your strategical play as well! The better you start recognizing the patterns from your tactical knowledge, the further you will be able to think ahead - hopefully further than your opponent. It works in both ways: On the defense, you might spot sooner that your position is weak to certain tactical motives - before your opponent can actually line up his pieces to exploit this instead of when the attack starts and it's too late. On the offense, you might spot the weaknesses to certain motives in his position and base your strategy around that (pressuring weak points in a way to force him to make concessions elsewhere because he needs to redirect his defenders).

I personally used the IdeaTactics app during an almost 10-year-long hiatus where I only did puzzles frequently while waiting for the bus etc., but did not play on-the-board at all. And I have to say that I am much better now that I started playing for real again, especially in the department of strategy! Of course, real games are good practice too, and you don't have to use this specific app (there are loads that do the same with the same quality). Good luck!

Comment to your analysis

Thanks for explaining your thoughts a little more! I have some thoughts about some of the moves, as well as your general strategy.

1-4: The opening is the Scotch, not the Italian Game (but who cares how it is called, this is just for clarification).

5+6: Good moves that delay his development.

6: While it generally is advisable to castle early, did you have in mind that the game tends to be a lot sharper when both players castled on opposite sides? Sometimes it is better to delay castling to see which side your opponent chooses. Since the queens are already off the board, your king is much safer from sudden mate attacks and can be allowed to remain in the middle for a few more moves. Castling here isn't bad, but it has implications. I would suggest 6.. Be7 first, development + coverage for g5).

7: Unfortunately, you don't give an explanation for Rd7. That move does nothing for your position at all except that it allows White a light pin on your knight in the next move. Where you scared about the possible fork on f7 and wanted to be sure? You didn't have to, because White had no way to attack f7 with another piece anytime soon (the queen was already gone and your bishop prevented his bishop to use the traditional Bc4. And Be2 can be met with Nf6 to control the h5 square while developing). To avoid the isolated doubled pawns, you probably have to play Re8, even though this loses the open d file for now (if Rd6, then Be3, threating Bc5).

9-11: Nothing to complain about.

12+13: The move b5 contradicts your plan from one move before: You force the white bishop to cover c2. Doubling his pawns on b3 might look nice, but it comes at the cost of opening your king's defense. Although, as mentioned, without queens you have a bit more freedom in that regard and your king is not threatened yet.

14+15: Good moves, put pressure onto your opponent.

16: Now your king is completely open. I see your idea, if White takes on c5, you can develop your bishop, free your rook on h8 and attack his knight. But, of course, he is smart enough to see it. Still, no harm so far.

17: Again, you completely step away from your plan from one move before. Remember, you wanted him to take on c5. Why destroy the bait now? Maybe you started feeling the lacking safety of your king, and indeed, he now has the option to pin your pawn with Rc1. You can however catch two flies with one hit: Kb7 not only moves your king out of the soon-to-be-open c file, but also covers the a6 pawn that will be undefended after the exchange on b4, which you can then still do next move with added safety.

18-20: The little combination looks fancy, but it is a terrible exchange in hindsight and the turning point of the game in my opinion. His knight was totally useless on e3 (virtually all of its forward moves are covered - even after it relocates to c2). Meanwhile, your bishop, even though still undeveloped at this point, isn't bad at all: It is a possible defender of d5, it can be used to attack his weak link on e3 some more (likely preventing him from castling) - while at the same time continue to put pressure on b4. Worse, the whole exchange frees White's own bishop to immediately pounce on d5. Your poor pawn structure was up to this point compensated by better piece activity, and you deliberately threw that compensation away. I'd still recommend Kb7 here. General rule of thumb: On the attack, you should not want to swap (unless you can force a mate/material winning combination by doing so) - after all, who is going to continue the attack when the attacking pieces are gone?

21: You felt like you had the momentum - big misconception. You just lost it without noticing, and have to start organising your defense now. You will lose either a6 or d5, but you won the pawn on b4 before, so that's okay. b4 does nothing for you, that bishop wanted to take on d5 anyways. Pressuring the opponent to do moves he intended anyways is not pressure at all.

22+23: Damn, if only your king had been on b7 already, then these moves would have been really cool and turned the game into a win once more.

24: Unfortunately, you have to move your king. I agree that your choice of Kb7 is better than Kd7 despite losing e6 as it doesn't open the king to checks from the rook on h1.

25-26: Reasonable, his bishop was much stronger than your knight.

Rest of the game: Let's face it, at this point you have lost anyways because of this reserve pawns on the kingside. Still, one last misplay before it could come to that, the promotion race. After 32 e7, you both have a similar situation: One rook blocking the enemy pawn, one protecting the own one from the side. You even had the additional advantage that your defending rook attacked his pawn at the same time. So how comes that..

..he hold off your promotion attempts with just one rook? Simple.. he never moved it away from the blocking position. To get past that block, you need at least one of your own rooks (to attack him from the side while covered by the pawn) and either the king or the other rook (to meanwhile defend the pawn).

..and got his promotion done using the other? With a little help from you. You did move your rook away from the blocking square. This greatly facilitates the described method: If he plays Rf7 and Rf8, with your rook still at e8, he only creates one threat (taking your rook with his) and you can simply take on e7 with the attacked rook, nullifying the threat. But after you moved the rook to b8, Rf8 actually creates two threats: Taking on b8 and promoting on e8. You can't cover both with the same rook, as now the attacked rook cannot take the pawn. The other rook is actually meaningless in this situation!

You could have resolved this particular problem earlier with 32 ..Rxe7, but you would have lost the resulting single rook endgame regardless. Maybe with slightly improved odds because your king would have been closer to the kingside compared to the continuation that happened in the game.

General Strategy

There were many good aspects in your play already, so don't give up hope! I also got a much better perspective on why you think you are lacking in the strategy department (correct observation). I think you still live too much in the here-and-now and do not consider longer lasting effects of your moves as much as you should. This goes hand in hand with how you evaluate the pieces (or don't). To you, you swapped two minor pieces (both 3 pawn units, so equal value) and got a pawn out of it (yay). What actually happened is that you swapped one vital of your own pieces for a useless piece of your opponent and a pawn, only to loose 2-3 pawns immediately afterwards as a consequence.

Thus my main advice is to push yourself to a different state of mind:
It is not important what a piece is, or where it is, what truly matters is where it can go. That knight on e3 was bad because it couldn't go anywhere useful soon. Your move 6 ..Be6 was good because now the white bishop on c1 couldn't easily go to a useful square (f7) anymore. This extends not only to the squares that a piece can directly reach, but also those where it can reasonably be without hindrance (e.g. the Be3-Bc5 manoevre to counter 8..Rd6).

If you look at squares rather than pieces, you can develop much better plans by going backwards: Think of the squares in your opponent's structure that you would like to control. Then backtrack and make a plan of how to get your pieces there. Your calculation skills seem to be quite decent, so you can make use of that. If you spot a structure that is vulnerable to some kind of tactic, think of how you can get your pieces into positions where you could actually execute said tactic. Or how your opponent can get stuff into position towards your own weaknesses, even before he starts doing it.

Also, don't be impatient if your opponent finds the right answers to deflect your threats. That does happen. If both opponents play perfectly for the entire game, it will end in a draw. Don't try to force things when they are not there. And remember that chess is a game of tradeoffs: If your opponent replaced a piece to cover a square that you threatened to attack, that piece now does not cover other squares anymore. Maybe you can now attack there?

All of this comes from experience. If you lose again and again because you moved your pawns away from your king, your brain will get the message at some point (as long as you correctly assess your mistakes). So if you want to get better, play, play, play. And look at your games afterwards to see where you went wrong! The best way to do this is in a club with better players that can guide you (you can't put all your games on StackExchange :P).


How to determine if a position is open or closed in a "rigorous" fashion? I am creating a set of chess positions to be used [as a data set] for a project. It's based on supervised machine learning, but I need to have labeled data (see more italicized text below) before any machine learning can be done. I wish to label each position as open or closed or possibly some combination of the two.

I started out with assigning each position to just "open" or "closed," but this wasn't clear for a lot of the positions. Then I decided to go with a third label, semi-open/semi-closed, which is like the middle and in between open and closed. I’ve labeled most of the positions, but there are many positions that I still haven’t comfortably labeled with a distinct class.

I know that open positions are characterized as having pawnless ranks, files, and diagonals, while closed positions have them clogged up with pawns. In open positions you can usually centralize your pieces, while closed positions give you a hard time moving an arbitrary piece to a random location on the board. There are many other related patterns, features, and qualities.

I can easily go with my gut feeling when assigning "closed" to a position that has 7 pawns on each side with each pawn blockading another, and "open" to a position that has pawns only on the flanks and in their starting squares. However, it's hard for me to classify some positions such as these two examples:

[White "Position1"]
[Black "Open/Semi/Closed/Etc"]
[FEN "8/5Qpk/p6p/P1b5/4pPn1/2Pp3P/1P1BbqP1/R3R2K w - - 0 1 "]

[White "Position2"]
[Black "Open/Semi/Closed/Etc"]
[FEN "3r1rk1/pp2pp1p/2p3pb/2P5/4P3/4nNPb/PP2P2P/R1RNK2B w - - 0 1 "]

What would you assign to the examples above and why? For example: one position is more open than the other due to characteristic XYZ, or the second position should not be considered closed since there's an open file, and so on.

Should I just ditch the whole binary-ish labeling (classification) and instead assign a variable number (regression) describing how open or closed a position is (e.g. 0% to 100% open?) Or is there still a way for positions to go into a few categories, which means that we can have "rigorous" definitions of the categories of openness? And "rigorous" as in having few contradictions and preferably can be applied by a human without too much difficulty.

As a chess player who currently studies computer science, I found this question very interesting so here's my thoughts on the topic. You already know how chess books categorize open and closed positions and you may also know that a semi-closed position is one with some of the characteristics of an open but not all. As you understand this makes the line between closed and semi closed positions not easy to be seen. So my recommendation is to use a number to describe the "openness" of a position(although 50% may be a problem). Now some things I thinks you might find useful for implementing you machine learning algorithm. Firstly, I will suggest you to take a look at this article https://chess24.com/en/read/news/how-do-chess-engines-think in the section about position evaluation. Now, some parameters you might use:

Number of pawns(a position with no pawns is apparently wide open).
Number of pawn moves(assuming a position with three pawns each,there's a big difference if they are on f2,g2,f7 and f7,g7,h7 respectively and if they are on c4,d5,e4 and c5,d6,e5.
As you see in 2 you may give an extra weight for pawn moves in the center. Generally it will be a good idea to give extra weight for anything open in the center. This will be more clear in 4.
Number of open and semi-open files. The ones in the center again should have an extra weight.
Open diagonals. Note that diagonals with one or more isolani should be counted almost as opens(As an example think about the Indian's bishop targeting d4 and b2 when the c pawn is not on c3). And you should of course take into consideration the length of the diagonal.

Note that essentially you don't judge the whole position, just the pawn structure. That's why count the available moves of every piece is a mistake. This just measures the mobility of the given piece and doesn't necessarily has something to do with the pawn structure. For example, in a position with no pawns a Knight on a1 has only two moves while in a closed King's Indian the f3 Knight has seven( only one is occupied by the King). Some of them drop the piece but they are legal moves nonetheless.

Hope that helps a bit!


How should black react if white plays "defensively"? I have heard that when White makes defensive moves, Black should take the center and be aggressive.

In such a case, is there a problem with Black making defensive moves too? Is that a bad idea?

Being aggressive and taking the center are two different things.

Regarding being aggressive, if White is making defensive moves, it's OK for Black to do the same as long as each move has a strong purpose.  For example, Black might fix flaws in his position by repositioning poorly placed pieces or securing his King.  If he instead chooses to attack and there are exploitable flaws, his attack can he blunted.

For example, if Black's King is exposed yet he attacked, White would have the opportunity to gain a tempo by moving an endangered piece and checking the King.  This is like giving White two moves in a row on the area of the board where the attack is happening.  Or, worse, White could play a Zwischenzug.  Both these things things make calculation difficult.  Better to first move the King to a safer square.

Taking the center, which is less aggressive, is rarely a bad idea, as long as one can hold onto the real estate.  Taking the center is good preparation for attack and gives one the flexibility in choosing how the attack should be conducted.


Reversed Sicilian - What's wrong with my plan? I played this game in a tournament and lost.

[fen ""]
[StartFlipped "1"]

1.c4 e5 {Starting the reversed sicilian} 2.Nc3 Nc6 3.g3 g6 4.Bg2 Bg7 5.d3 d6 6. Nf3 Nge7 7. O-O O-O 8. Rb1 h6 {Finished the Closed Sicilian setup that I want: h6, Nc6, Ne7, O-O, Bg7, g6, and the d6-e5 pawn chain. This is the exact reverse of Karpov's Closed Sicilian when he is white} 9. b4 {I always want this move by my opponent when playing the Closed Sicilian because his Knight can be a target, but I also needed to oppose his queenside plan, though I was not really sure how to do that. I was thinking that I should try to close the queenside so that I can focus on my attack on the kingside} a6 {I couldn't think of any good way to frustrate his queenside attack, so I played this move because I have seen this in some Karpov's games, but I don't really know its purpose, I just "hope" that I can close the queenside in the future with this move} 10. a4 f5 {Started to attack his unsupported Knight} 11. b5 axb5 12. axb5 Nb8 {I did not know where to put my Knight, but I was thinking that the c5 square will be a good outpost for my Knight, so I retreated to b8} 13. Qb3 Be6 {The purpose of this move is to prevent a possible discovered check} 14. Nd2 Nd7 {Preparing to post my knight to the c5 square, so my b-pawn can't be taken because of the fork threat} 15. Ba3 Rb8 16. Na4 b6 {Closing the queenside at last} 17. Nc3 f4 {Starting my attack on the kingside. My plan is to post a Knight to d4 via the f5 square, then after posting the Knight to the d4 square, I was thinking of attacking the f3 and the e2 squares} 18. Nde4 Nf5 19. Qc2 Nd4 20. Qd1 Nf6 {Vacating the d7 square for my Queen, I was also thinking about removing my opponent's light-squared Bishop to help my attack on the f3 and the e2 squares} 21. Nxf6 Qxf6 22. Nd5 Bxd5 {Now my time trouble has started. I was thinking about putting my queen to Qf7, but after that, there was nothing that I could do to remove his Knight. Then I thought that by simplifying things, I can win a pawn by playing Nc2 at move 27, yes I calculated that, but unfortunately it was a blunder.} 23. Bxd5+ Kh7 24. e3 fxe3 25. fxe3 Qxf1 26. Qxf1 Rxf1 27. Kxf1 Nc2??? {I thought I could win a pawn here that's why I started simplifying things starting from move 22, so I played this move very quick, and immediately after playing this move I realized that I already lost the game} 28. Bc1 e4 29. Bxe4 d5 30. cxd5 h5 31. Ke2 Bf8 32. Bb2 Na3 33. Rf1 Nxb5 34. Rf7+ Kg8 35. Bxg6 Ra8 36. Be5 1-0

I have added comments at the following moves:
1, 8, 9, 10, 12, 13, 14, 16, 17, 20, 22, and 27

I don't really understand how to handle the pawn structures at the queenside.

Is there something wrong with my plans, my thinking process?

My opponent claimed that he was winning the middle game, but I think he was wrong, I think I was winning the middle game here. Am I wrong?

Thanks!

8. ... h6 was unprovoked. Until White threatens to double Q+B on a c1-h6 diagonal, or places the piece ag g5, there is no reason to weaken the Kingside. The plan calls for immediate 8. ... f5, e.g. 8... f5 9. Bg5 h6 10. Bh4, and it is up to Black to decide between 10. ... g5 and 10. ... Bf6, whichever suites your style.

Along the same lines 9. ... a6 seems off. Black shouldn't help White in opening Queenside files. If you want to secure Queenside, 8. ... a5 is in order of the day.
Did you consider 12. ... e4?


What locations in the USA have FIDE approved tournaments frequently? USA does not have a lot of FIDE tournaments.

Are there any locations that have them more often than some small areas that may only hold one and never do another one?

All FIDE rated tournaments have to be registered in advance with FIDE. Once registered with FIDE they appear on the FIDE website. The page for the USA is here.

As you can see the US is very poorly served for FIDE rated tournaments. The main centers are New York, San Francisco, LA and St Louis.


What are some of the checkmates with very few moves? I would like to learn about a few checkmates using very few moves. I know a one where you develop the knight and march it directly towards the King. Does anyone know the name of this mate and suggest others?

There are probably as many quick mates as there have been first time players (since we all get caught in these at the start!) but here are a few common ones:

Fool's Mate

This is the shortest possible checkmate in a mere two moves:

[FEN ""]

1. f4 e5 2. g4 Qh4# 0-1

White can also play f3 instead of f4 or move the g pawn before the f pawn.

Scholar's Mate

This mating pattern is also sometimes referred to as "Fool's Mate" and there are two main patterns:

[FEN ""]

1. e4 e5 2. Bc4 (2. Qh5 Nc6 3. Bc4 Nf6 4. Qxf7#) Nc6 3. Qf3 Bc5 4. Qxf7# 1-0

The key is that f7 is insufficiently defended and mate is delivered there.

Légal's Mate

Légal's Mate (also spelled as Légall's Mate) is probably the mate referenced in the question:

[FEN ""]

1.e4 e5 2.Nf3 Nc6 3.Bc4 d6 4.Nc3 Bg4
5.h3 Bh5? 6.Nxe5! Bxd1?? 7.Bxf7+ Ke7 8.Nd5# 1-0


The Bishop's gambit variation of the King's gambit I've been investigating the theory of the King's gambit, and I found the variation in the accepted 3. Nf3 Be7. I didn't like the looks of that for White.
I've started to play the Bishop's gambit, but the problem is that Black can also play the 3... Be7 line. Is there any way to deal with it?

After 1.e4 e5 2.f4 exf4 3.Bc4 Be7 4.Nf3 Bh4+ probably 5.g3!? fxg3 6.0-0 does the job.
[fen ""]

1.e4 e5 2.f4 exf4 3.Bc4 Be7 4.Nf3 Bh4+ 5.g3!? fxg3 6.O-O

In typical King's gambit style, you're down in material and probably a bit worse with perfect play, but you have great compensation and attacking chances. If Black makes a mistake, they will pay the consequences.


How to calculate the number of positions in chess? For  layman, can someone explain how you calculate the number of available positions in a chess game, and how do you get the huge number of 10^120 or 10^46?

We can easily get a reasonably good upper bound on the number of positions. At any point in time, each player has 16 pieces of which the 8 pawns can perhaps be promoted to a knight / bishop / rook / queen. Consider all captured pieces to be off the board but part of the position (this would increase the number of positions but that is fine because we only want an upper bound). Thus in each position the number of combinations of pieces each player has is less than 58. Place the kings on the board first. There are less than 642 ways to do that. Line up the 30 other pieces in any order and place them one by one on the board or off the board (captured). There are at most 6330 ways to do that. This gives a total of less than (58)2×64^2×63^30 < 6×1068 positions. Double that to include whose turn it is. I had ignored castling rights; you can check that it is negligible by similar calculations.
This bound is very much smaller than what you gave in your question, even though it is an extremely loose upper bound, because you had a misconception. The number of possible positions is not at all the same as the number of possible games. For example, there are less than 642 positions with just the 2 kings, but at least 2100 possible games starting from any such position (under the 50-move rule but ignoring 3-fold repetition rule for easy estimation). Moreover, the 10120 estimate is assuming the game lasts 40 moves (2 plies) and each move has about 1000 possibilities. The real total number of possible games (including stupid ones) is obviously way more than that, since we already have 2100 possible KK games alone!


Leaving the score aside, what are the criteria allowing Stockfish to choose its "best move"? I'm trying to understand how a chess engine like Stockfish works. I use Stockfish 10 directly, without an UI.

For example, for this position (white to move)...

r3n1k1/1bpp2pp/pp2p3/2P1P3/R2P4/3B1rPq/7P/1Q3RK1 w - - - 0 26

...Stockfish (depth limited to 31) returns the following informations; I only kept the last lines, eliminating those where the depth was less than 31:

info depth 31 seldepth 47 multipv 1 score cp -771 lowerbound nodes 86977322 nps 1898570 hashfull 990 tbhits 0 time 45812 pv f1f3
info depth 31 seldepth 47 multipv 1 score cp -761 lowerbound nodes 87198087 nps 1898499 hashfull 990 tbhits 0 time 45930 pv f1f3
info depth 31 seldepth 47 multipv 1 score cp -790 upperbound nodes 99439222 nps 1905696 hashfull 992 tbhits 0 time 52180 pv f1f3 b7f3
info depth 31 seldepth 51 multipv 1 score cp -788 nodes 134293602 nps 1906577 hashfull 995 tbhits 0 time 70437 pv d4d5 f3f1 d3f1 h3h5 c5c6 d7c6 a4h4 h5e5 b1h7 g8f8 h4f4 e8f6 h7h8 f8f7 d5e6 e5e6 h8h5 f7e7 h5f3 a8e8 f4c4 b6b5 c4c2 e7d8 f3d3 d8c8 c2e2 f6e4 d3e3 c6c5 f1g2 c5c4 g2e4 b7e4 e3d4 b5b4
bestmove d4d5 weight f3f1

I don't understand what criteria allow Stockfish to say that d4d5 is the best move.
The line corresponding to d4d5...

info depth 31 seldepth 51 multipv 1 score cp -788 nodes 134293602 nps 1906577 hashfull 995 tbhits 0 time 70437 pv d4d5 f3f1 d3f1 h3h5 c5c6 d7c6 a4h4 h5e5 b1h7 g8f8 h4f4 e8f6 h7h8 f8f7 d5e6 e5e6 h8h5 f7e7 h5f3 a8e8 f4c4 b6b5 c4c2 e7d8 f3d3 d8c8 c2e2 f6e4 d3e3 c6c5 f1g2 c5c4 g2e4 b7e4 e3d4 b5b4

... proposes a score ("cp score") equal to -788 which is smaller e.g. than -771 (see the following line) by example:

info depth 31 seldepth 47 multipv 1 score cp -771 lowerbound nodes 86977322 nps 1898570 hashfull 990 tbhits 0 time 45812 pv f1f3

If it is not the cp score that is decisive, what is the criterion used?

Any help would be appreciated !

The first three lines:

info depth 31 seldepth 47 multipv 1 score cp -771 lowerbound nodes 86977322 nps 1898570 hashfull 990 tbhits 0 time 45812 pv f1f3
info depth 31 seldepth 47 multipv 1 score cp -761 lowerbound nodes 87198087 nps 1898499 hashfull 990 tbhits 0 time 45930 pv f1f3
info depth 31 seldepth 47 multipv 1 score cp -790 upperbound nodes 99439222 nps 1905696 hashfull 992 tbhits 0 time 52180 pv f1f3 b7f3

Are not actually complete searches. The lowerbound and upperbound following score cp ... indicates that the value is not the actual value of the move. Instead, the value is a bound that was obtained when stockfish failed outside of its aspiration window.

When this happens, Stockfish needs to perform a search at the same depth again, with a wider aspiration window. This is why you have 4 lines at depth 31: stockfish searched the position a total of 4 times at depth 31 because it failed outside of its aspiration window 3 times in a row. The first three scores are not exact, and hence only the score from the 4th search (which is exact) is used to determine the best move.

So the criterion used to determine the best move is the internal score of the deepest search which did not fail outside of its aspiration window.

The internal score differs from the cp score in that stockfish evaluates positions with a granularity of 1/256 of a pawn, rather than 1/100 of a pawn. So two positions may have the same cp score, but stockfish may still be able to rank them internally.

The answer changes again when stockfish uses multiple threads. In this case, a voting system is used, where each thread has a different voting weight based on its score and max depth reached.


Draw offer without executing move Scenario: It's Player A's move, and without executing a move he offers a draw. Player B replies "Please make a move". Player A then makes a move, where upon player B says: "Ok, I accept". Is it now possible for Player A to say that the draw offer no longer stands, and was in fact nullified when it was not originally accepted during the period between the offer and the move that Player A did?

No, Player A cannot do this. FIDE rules of chess article 9.1.1:

  A player wishing to offer a draw shall do so after having made a move on the
  chessboard and before stopping his clock and starting the opponent’s clock.
  An offer at any other time during play is still valid but Article 12.6 must be
  considered. No conditions can be attached to the offer. In both cases the offer
  cannot be withdrawn and remains valid until the opponent accepts it, rejects
  it orally, rejects it by touching a piece with the intention of moving or
  capturing it, or the game is concluded in some other way.

Key parts highlighted. Player A made the draw offer at one of these "other times", so it's still valid and cannot be withdrawn. Player B asking player A to make a move, and player A actually making a move, are not one of the four actions that can terminate the draw offer, so the offer remains valid.


What are white's plans in this Scotch Gambit position? I'll skip the long explanation, but it's not uncommon for me to reach the following position as White out of the opening:

[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.d4 exd4 4.Bc4 Bb4+ 5.c3 dxc3 6.O-O cxb2 Bxb2

(Black to move, most common replies seem to be ...Nf6 and ...f6, though ...Bf8 is also occasionally played)

A number of sources claim that this position is perhaps equal but White has good chances, and in practice I do alright. The problem is that I have trouble coming up with any short-term plans because White has almost completed development but Black's 'neutral' position means that there is little to do tactically and I'm concerned that by making too many passive developing moves (rooks onto open files, etc.) I'm wasting the development advantage that I've spent material to gain. I can see that here White has pressure on f7 and g7, and there is the possibility of tactics after Re1, but I struggle to come up with a concrete short-term plan.

So, in short, what are White's short-/medium-term plans?

you next moves as white will be 7. Ng5..  and you will activate your Queen - dependig of the Blacks move it may be 8.Qf3 or 8.Qd5

Attack the King and use weakness for f7

Some exmaples:

[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.d4 exd4 4.Bc4 Bb4+ 5.c3 dxc3 6.O-O cxb2 7. Bxb2 Nge7 8. Ng5 O-O 9. Qh5

or:

[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.d4 exd4 4.Bc4 Bb4+ 5.c3 dxc3 6.O-O cxb2 7. Bxb2 Bf8 8. Qd5

7. ... Nf6

[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.d4 exd4 4.Bc4 Bb4+ 5.c3 dxc3 6.O-O cxb2 7. Bxb2 Nf6. 8. e5

or

[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.d4 exd4 4.Bc4 Bb4+ 5.c3 dxc3 6.O-O cxb2 7. Bxb2 Nf6. 8. Ng5

7. ... f6

[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.d4 exd4 4.Bc4 Bb4+ 5.c3 dxc3 6.O-O cxb2 7. Bxb2 f6. 8. Qd5


What plan should I have followed in this particular position? I played a game today where I feel that I had a nice positional advantage (the computer supports my opinion) but I only managed to draw it in the end. This is the position that I consider to be critical:

[fen "2bq1r2/1r1np1kp/pp4p1/2pP1pP1/2P1NQ2/3B3P/PP3P2/R3R1K1 w - - 0 1"]

I am playing White. Here Black played has just played ...f5 and my following moves were Ng3 and h4 (after Rf7). I still had some advantage at that point according to the computer but I lost it a couple of moves later after some inaccuracies. What plan should I have followed? What are White ideas to win in this position?

Black is very weak on the black squares, on the e file, his e pawn is very weak and his knight and bishop are short of good squares because of his cramped position.

You should try and get your knight to f4 and double your rooks on the e file. I would start with Nc3. This also helps against Black's obvious plan to undermine your center and give himself more space with b5. You may need to play a4 at some stage to control b5 but your immediate priority should be to double on the e file. Once you control the e file you want to either win his e pawn or invade on the e file.

At the same time your queen can exert more control over black squares in his position, either from h6 or maybe along the long diagonal from b2 or c3.


What type of hardware is the most important for analysing with Houdini? I am going to analyse a lot of games with Houdini 3.

The system on which I am going to analyse it is really powerful, but I am curious, what is the most important type of hardware for such analysis?

CPU
RAM
GPU

I am willing to buy some additional computational power, but if needed.

Up till now I have read this and was not able to find the answer.

If someone has any results or have done a strong analysis with Houdini, please give your insights.

You have not read enough of Houdini's online user manual. First look at the 2.1 Installing Houdini page.

Specifically, it says you'll get 30% faster performance with 64-bit over 32-bit. It says it's optimized to use up to 6 cores. And Intel i5 will run it faster than an equivalent speed AMD Opteron. Their home page says it will use up to 4 GB of RAM for hash memory. Obviously from that, you'll want to get the highest clocked Intel i7 you can find with a 4th generation CPU.

But if you get Houdini 3 Pro instead of Houdini 3 Standard, it supports up to 32 cores and 256 GB of hash memory and NUMA-architecture (whatever that is). Their example performance comparison shows on a 16-core dual AMD Opteron-6128 box that Pro has a 20% speed gain over Standard. With the Pro version, you'll want as many cores as you can get, because that's the number of threads you'll be able to run at once. Intel i7 will likely be better than AMD for the Pro version as well.

Definitely read everything in the online Houdini 3 User's Manual, especially section 3 about its configuration. That tells you how to optimize it.


How do I spend time on chess in boring meetings? I will be sitting in two boring meetings and each one is several hours long. I do not need to participate in any way, nor is the information from the meeting useful to me. However, my presence is expected and I am not supposed to look at my books, phone, notebook, etc; but a quick glance at a piece of paper may be tolerable. Chess is my hobby and I am seeking advice on spending time mentally on chess during such meetings. By the way, right now I am unable to play blindfold chess.
Any ideas on how can I enjoy chess in my mind in such situations?

One posibility is to concentrate in problems.
Write on paper the posicion description, using a notation like the following:
This fen:
r1bqk2r/pppp2pp/2n1pn2/5p2/2PP4/5NP1/PP1NPPBP/R2QK2R b KQkq - 0 7

Corresponds to:
W-Ke1,Qd1,Ra1,Rh1,Bg2,Nd2,Nf3,Pa2,b2,c4,d4,e2,f2,g3,h2
B-Ke8,Qd8,Ra8,Rh8,Bc8,Nc6,Nf6,Pa7,b7,c7,d7,e6,f5,g7,h7
Black to move.

Annotate your answer as a continuous line of moves without the move numbers to simulate note taking.


Backwards Chess Program Is there a chess program where you can create a position and the program creates a game, expecting the best possible moves to get there, or the most common?

A problem I would see is some positions might require a terrible move to get there, or have really extensive games to get to that point.

I feel like this could create creative attacks

-Most common= most frequent move, such as how e4 is commonly responded with e5 even though stockfish rates c5 (Sicilian defense) as a higher value choice via the Aplha-Beta Pruning Algorithm.

-"Best" move= pretty much what stockfish/Komodo/ Houdini
Would choose as their algorithm chooses the highest value, safe move, as their programs can go deeper than our abilities

I think this is doable. However, it will depend on the number of pieces in the required position.
You see that many openings can be reached in multiple ways
(X,Y,Z,...) -> P; where X, Y and Z are the sets of moves that get you from the initial position to the required position P.

This problem is NP-hard, because you can never know for sure which road was selected!

The best way for you is to study the positions of known games (which is most of the time is the case). Then search for [1] the game and play it back from the beginning.


Engine with emphasis on strategic/positional analysis Are there engines are especially recommended for strategic/positional analysis? I'm especially looking to use the engine in complex, opening position.

Chess engine is just a tool, your question is like asking which calculator your should use for learning mathematics.

An engine will just give you a score and a computer line, it tells you what you should play but it doesn't tell you what you shouldn't do.

You'll need to work hard, and use the engine to aid your analysis. Consider to pay for a human chess coach.


Why is exposing my queen for capture better in this position (According to computer analysis)? In one my of my game, the following position appeared (me white):

Computer analysis says that I should have played Nf3 (exposing my queen being captured by the bishop). In the proposed scenario by the computer, the opponent will play h3 (capturing my knight) and so I can capture his bishop with my queen.

But another scenario could occur, the opponent will capture my queen with the bishop and I can then play Nf7 (something like the fried liver) and the opponent moves his queen and I can capture the rook (Or he can capture my queen and I capture the bishop with the rook but in this case he can then move his queen to prevent the somewhat-similar-to fried liver attack). But In such case, I think the opponent is in a better situation: He got my queen and I got a pawn and a rook (or a pawn and a bishop), He can no more castle but he has much more material so he can do well.

So why does the computer says that this is a better move? I tried h3 to attach the opponent bishops but computer says this is not a good move!

An explanation for why such an analysis is valid is highly appreciated

Your description of the computer's suggestions doesn't quite match the position, but if you mean the computer suggests Nxe5, that is correct, as Bxd1 leads to a variation of Legal's Mate.

Nxe5  Bxd1
Bxf7+ Ke7
Nd5#

If, instead,

Nxe5 dxe5
Qxg4

and white has won a pawn, and has a big lead in development.


Black opening sequence that is equally solid versus d4 and e4 Is there an opening sequence for black that is equally solid versus d4 and e4?  Obviously you have to take into account white's subsequent moves, but the goal would be to have an opening where the first, say five or six or so moves (maybe with variatios  in move order as needed), would be solid against most common e4 and d4 openings.

You could try Owen's defense, which is very much under-represented in all levels off chess in my opinion. Smirnov's 2-part series is nice and clear (although sometimes slightly over-simplified maybe), and he has another 2-part series about using this strategic system with the white pieces.
I would recommend playing the Colle-Zukertort at white a bit, the ideas are definitely useful for the b6/b3 systems. This also provides a very comfortable and active setup to shoot for as black when your opponent does not put a pawn on e4. The themes from the Breaking Stereotypes series provide some nice complementary insights for these positions as well.

Another option is the Sniper, which is a lot of fun to play and is maybe even more systematic as far as strategical planning is concerned (get king's bishop to the longest diagonal by playing 1. .. g6 2. .. Bg7, then play for central and queen-side activity via the dark squares by playing 3. .. c5) but it's significantly less forced which means the total amount of relevant theory is a lot larger. Also you might end up in some fairly theoretical positions, or positions that are really though to play unprepared. Super flexible though.

And then there's the Hedgehog, which is by far the most systematic and repeatable chess opening I know of. It's not uncommon to play the same 10 to 13 opening moves five times in row or even more, without your opponent even following theoretical variations.
   (btw John Bartholomew is excellent at teaching chess through actual understanding so that's an unrelated recommendation)


How do strong players know opening ideas, plans, etc? A scenario that already happened many times. "GM X" comes out with this new book on "Defense Y" and this book becomes an instant classic for its lucid, clear explanations of the Defense's main themes, ideas, tactical motifs, etc. etc. Assuming that chess knowledge is learned from books, and that there was no previous such book on "Defense Y", how did "GM X" learn all these ideas, plans, etc? Did he learn by himself, playing and analyzing game after game played with "Defense Y", then got all his conclusions about the opening plans? Is there some secret "oral transmission of knowledge" among strong players, GMs, etc. so that other GMs told him what the plans are? Or else?

This kind of book is usually a work of synthesis. The author looks at the available games and takes notice of the various plans employed. It is a matter of noticing and making notes and then writing up a synopsis. An opening book can be written without prior personal experience with this opening. One can also discover a new plan, either by one's own thinking or by looking at the way an engine plays.

Sometimes ideas are transmitted orally. Bologan's book on the King's Indian Defense is by his own admission written on the basis of the notes he took while being tutored by his guru Lanka.


Why is 3. Nc3 played in mainline of the Modern Defense? After:

[FEN ""]

1. e4 g6 2. d4 Bg7

by far the most common third move is 3. Nc3. This goes against the principle of not blocking the c pawn with the knight as white, now of course principles can be broken but I can't see the benefit of doing so here.

The e4 pawn does not need defending, and if the aim is to stop 3... d5 then 3. c4 achieves this as well, then Nc3 can be played later.

So why is it not preferable to play 3. c4 before Nc3?

3. c4 will likely transpose to a King Indian defense while 3. Nc3 will likely lead to a Pirc. 1. e4 players will prefer the more familiar Pirc positions.

The Modern Defense move order lets White decide the main position.


Chess movie as educational incentive I am trying to encourage a young friend to learn chess. He is very interested, just like any child would be with a child's play. I am wondering which movie about chess to choose, that could cause more interest and improved learning to him.

Searching for Bobby Fisher maybe.
Trailer: https://www.youtube.com/watch?v=8khmNiamBxo

http://www.imdb.com/title/tt0108065/


Is It Good Or Bad To Trade Too Much? One aspect of my style in chess is that I like to trade a lot.

Is trading too much bad?

Trading for the sake of trading is bound to be in your opponent's favour more often than not.

Generally speaking, recapturing often activates the piece that can capture back. Consider two rooks on an open file, both protected by another, pretty passive rook on the a-file. The side that trades loses control of the open file and is stuck with the a-file rook, but the sides that recaptures gets to move his previously passive rook from the a-file to the open file.

Also, if you delay trading, you keep options open. As long as you still have several options, the opponent has to keep defences up against all of them, but as soon as you actually choose one (make the trade), that releases tension and usually frees up the game of the opponent a bit. Don't release tension without a reason.

Worst, if the opponent knows that you like to trade, he may offer trades that work in his favour positionally, and you'll go for them. That will get you a bad position very quickly.

A trade is a way to change the nature of the position. Only go for trades that change the position in your favour, otherwise keeping the opponent guessing is better.


What are weak squares in chess; how can they help to mate another player? I read this concept in a book but I didn't understand much about the concept. Can anybody explain this concept with an example?

This is a very common example.

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

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


What are the biggest free chess databases? Is it legal to download games from them? Are there some free chess game databases where it is possible and allowed to download games? Is it possible to use this information for my own purposes? For example, would be allowed to make a machine learning app that learned from the downloaded games?

FICS database

Lichess database

Million base 2.2

PGNMentor

Is it possible to use this information for my own purposes

Absolutely! Nobody has the copyright. Enjoy your machine learning adventure!


Piece down vs rook for bishop exchange I was recently in a situation in which my bishop was pinned with my queen behind it and my only options were
- losing the bishop.
- defending with the rook which would allow an exchange of my rook for his bishop.

I know both cases are bad but, which one would be worse, or should I say less bad? It could maybe depend on the position as well but I'm looking for an "in general" kind of answer.

Thank you.

In general, it is better to be an exchange (rook vs. minor piece) down than a minor piece. If you look at the standard table for piece value, you see that being an exchange down is only 5-3 = 2 points, while being a minor piece down is 3 points.


Why are there no more adjournments? I keep reading about adjournments in books, but why don't we use them anymore? They seem like cool analysis sessions.

Primarily because computers have rendered adjournments obsolete. In addition, with the advent of digital clocks with delay or increment, it is much more fair to have people play it out over the board. It is much better to have the players decide it than having a team of people helping them overnight, or nowadays, a strong computer.


1998 USCF Chess Rankings Is there a place to look up rankings of USCF players for a previous year?  Specifically, I would like to know who was #3 in the USCF in 1998 (for reasons not relevant to the question) - but figured a broader question would be more useful to others.

I tried USCF's Top 100 Lists, but it doesn't seem to go back nearly that far.  My other Google searching turned up even less.

At one time, there was an annual rating list published each year in the January issue of Chess Life.  They don't do that anymore, and I'm not sure if they still did it in 1998 (or, I assume what you'd really want would be such a list that would have been published in January 1999, which would have the year end ratings for 1998).  If they still did, if you can find a library that has back issues of Chess Life, you could look there.  Or, House of Staunton / USCF Sales has the January 1999 back issue available for $1.00.

If you can find someone who has been a USCF TD for that long, and if they're a bit of a packrat, they might still have the 1998 annual rating list, though you'd have to sort it yourself.  And it might be on floppy disk...  I looked on the USCF web site in the TD/Affiliate area, and they don't have rating supplements online that go back nearly that far.


Calculation for game phase What is the best or alternative ways to detect game phase by a chess AI? What is a good algorithm to use? Chess programming wiki says to count material or pieces? What would be the expected piece or material counts to use?

I have an idea to use average pieces on a file and its standard deviation but that’s intensive math to use? And I’m unsure of its applicability?

This is a tricky question, and I'm sure there's no definitive solution.

Lichess uses this definition (https://lichess.org/qa/102/how-are-the-mid-game-and-end-game-dividers-determined)

Opening is obvious, starts on move 1.

Mid-game is less obvious, and is still in testing. The long-and-short of the current heuristics are that the mid-game occurs when either:
- The position is adequately complex and enough pieces are developed.
- 2 sets of minor or major pieces have been taken off the board. (This is mainly useful for when the position is quite open)

End-game is slightly more straight forward, when there are less than 7 minor and major pieces on the board the end-game has begun (so, perhaps 2 rooks and a bishop Vs 2 bishops and a knight). This is not technically where everyone would draw the line, but it's a good indicator that either 1. The end-game has begun 2. The end-game will begin soon.

Stockfish uses interpolation between the middlegame and endgame. This is done by counting non-pawn materials (https://github.com/official-stockfish/Stockfish/blob/03a9b3bd8d79e1677f1c74cf7d8f8036795675c6/src/material.cpp)

// Map total non-pawn material into [PHASE_ENDGAME, PHASE_MIDGAME]
e->gamePhase = Phase(((npm - EndgameLimit) * PHASE_MIDGAME) / (MidgameLimit - EndgameLimit));

You will need to make a decision on what material counts you want to use.

Suggestions:

If your engine supports opening book, you might want to use that
You might use the move counts (it's in the FEN string) for opening vs middlgame
Endgame is generally defined as number of X pieces and N pawns on the board (you decide what X and N should be). N<=3 is almost always an endgame.
Lichess's definitions have worked quite well practically.


How do I install SCID Chess on a Mac? I tried to download SCID for Mac and when I downloaded the latest version, I got a scid-src.zip. When I extracted this, I get a bunch of folders and source files. How do I launch this application? I see no launcher file.

Thank you,
Sean

I don't think SCID supports Mac OSX officially. The files you have are raw sources, which you'll need to compile with TCL. Why not try a newer (and better) SCID alternative?

Download SCID vs PC

http://scidvspc.sourceforge.net


Why Kirsan Ilyumzhinov is so popular in the chess world? Kirsan Ilyumzhinov has just been re-elected as the next FIDE president again. He's so far beaten two World Chess Champions in the elections - Karpov and Kasparov, both by some absolutely big margins.

What is his claim to (chess) fame?" What do people like about him to give him so much power? He's the real king in chess, the most powerful chess personnel in the world and dominating the chess scene.

I thought that Nigel Short summed it up pretty well here: http://www.chess.com/news/breaking-ilyumzhinov-beats-kasparov-110-61-at-fide-presidential-elections-4528

"There's nothing wrong with chess players. If you ask in the playing hall, I'll bet 9 out of 10 will vote for Kasparov. The problem is: delegates. If the delegate has received an incentive to vote in a particular way, it doesn't matter whatever reason or logic is presented to him."

Basically, many delegates voting for Ilyumzhinov received some strong form of compensation to do so. He consistently wins because he has money (much of which he gained while ruling Kalmykia) and has zero moral compunctions about how he uses it.


Making an inferior move to get out of threefold repetition? Let's say it's the last day of a tournament and white needs to win a game in order to advance to the next stage or something like that. Unfortunately, he reaches a position where there is no way to progress without making things worse somehow, and so he begins repeating the same position.

However, he doesn't want to claim a draw since it would ruin the tournament for him. Black realizes what's going on and also refuses to claim a draw, hoping that eventually white will give in and make an inferior move in an attempt to win.

Would black's behavior be considered unsporting in such a situation? Has something like this happened in a tournament before? Could this theoretically go on forever in a game with time increment?

Could this theoretically go on forever in a game with time increment?

No, because the arbiter would step in and declare the game drawn after the fifth repetition of the position.

According to the FIDE Laws of Chess -

  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.

and -

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


Am I improving my tactical knowledge by explaining solutons to my wife? I recently started to teach the game to my wife, yay for me :) So now she's somewhat comfortable with how the pieces move and the basic opening principles but as soon as she gets to the middle game she never knows what to do next so I started showing her tactical puzzles, we are doing the book by Fred Reinfeld "1001 Winning Chess Sacrifices and Combinations".

Since she is not experienced once I've set up the position I see the solution and explain to her the tactical weaknesses in order to point her in the direction of the solution. She still needs some time to find it but eventually she gets it.

My question is, since I am not finding the solution by myself it would seem that I am not benefitting from these exercises but since I explain to her in detail that in a particular position there is a weak pawn, or an overload piece or a way to force a pin could this be helping me as well or the only way to improve tactical knowledge is by solving the puzzles, period?

Since you are teaching your wife, who's new at chess, these tactics are perhaps a bit too easy for you. They probably won't do much for your standard game.

That said, by explaining the patterns to her and doing a lot of 'easier' tactics, you are definitely helping your blitz/bullet games.

Basically you'll be able to see tactics faster in your games, but your ability to see more complicated tactics is remaining more or less unchanged. To really hone your tactics, you're going to need to improve your ability to calculate deep, and consider several different lines when perhaps the solution isn't as obvious.

Teaching is great for reminding yourself of the basics, but if you want to improve, you're going to need to do more than teach. Find some more difficult tactics for yourself, play some challenging games, study more opening lines, and analyze your shortcomings.

Hope this answers your question.


Why do modern Grandmasters prefer playing quiet openings? I am rated 1450 and I am have been analyzing GM level games since I began playing chess. I noticed that most GMs consistently play balanced almost boring openings against each other and that only a handful of top level GMs consistently play double edged/ aggressive openings.
For example MVL is one of the few top players that plays the Sicilian as black exclusively. Finally I want to make it clear that I understand that while most openings aren't as crazy as as the Sicilian (at GM level) I know that they are complicated and challenging in their own right.

Aggressive openings often rely too much on preparation and most top players would rather play something "quieter", trying to outplay their opponent later on, rather than exposing themselves to being surprised by a novelty thier opponent spent hours or even days analyzing at home.
Also note that the theory of some of those "sharper" openings is so deep these days that sometimes they're just "known to be a draw". Take the Poisoned Pawn variation of the Najdorf Sicilian for instance.
That being said, it's worth noting that lots of interesting and even "chaotic" ideas are appearing all the time in openings that used to be considered "quiet".


Is it possible to extract "sub-scores" from an engine's evaluation? Does anyone know of an engine that gives "sub-scores" (e.g., for material, king safety, space, activity) in addition to its total evaluation? Lots of people have wished over the years that engines could help players understand why their moves are bad, and although having access to sub-scores wouldn't be a total solution, it might help. Even if the engine doesn't output these scores directly, if they're part of the evaluation--and if the engine is open-source--a sufficiently interested user might be able to make use of them.

Of course, I'm assuming that something like a "sub-score" is part of some modern engine's evaluation function. They could all be too advanced and/or non-linear for that now.

What about?

The eval command will do what you want. However, it's not useful for chess learning. They are just static evaluations. What you're after is more like extracting features from the analysis. Stockfish doesn't have it.


How to get to 2000 ELO rating I'm a 1800 chess player.

I know pretty much all the basics in every fields of the game.

I know the main lines of openings, I know tactics, I know end game. Average in all of it (=1800 player). I would say I'm a little bit more of a tactic player though.

I know that I need to study to get to 2000 which is the dream for me.

My question is:
What would be the best things to train to really get to 2000 ELO without too much work?

Should I become a tactical beast and just learn easy openings?
Should I dig deeper in all openings (which is a pretty big work)?
Should focus on finals?

I know all of this important, but it's a lot of studying for these 200 points I'm missing. I really wonder if there's a shortcut to reach just 2000, I don't plan to become a master with all the knowledge needed for that.

The best thing to train is (almost) always calculation:

Get a set of maybe 1000 3-5 move combinations and go through those problems until you basically know them by heart. That's to enable pattern recognition.
Apart from that set, concentrate on calculating long variations in your training instead of just seeing tactical shots. The Yusupov books are a good source.
Maybe try to learn to play blindfold. That demands a lot of concentration and improves your visualisation

The next best thing to train is positional understanding:

Play tournament games against strong players.
Analyse these games with strong players.
A big part of positional play is connected to typical opening setups. So if you spend time on the opening, spend it by learning about typical ideas.
This Aagaard book I liked.

I wouldn't worry too much about the endgame or the opening. Good endgame play builds on strong calculation, good opening play builds on positional understanding. Just learning stuff by heart without having this foundation is not going to benefit you much. And the essentials you'll probably pick up anyway.


Solving a problem from a Jan Prezewoznik book The following position is White to move:

[fen "1Q5r/1p2kppp/1q2b3/r1p3P1/p2pB3/P2P3P/1PP1P3/1KR2R2 w - - 0 1"]

I'm a newbie in chess and I want to know, how to solve this problem in a quick way.

The nature of the problem that this position presents is first this: to correctly assess the situation on the board, and in particular to recognize the immediate and impending problems White is facing. As this answer will show, there is a lot of concrete analyzing one can do from this position, but the point I want to stress is that just answering that first question (and with only simple calculating) goes a very long way toward narrowing down what moves are even reasonable to consider, and can ultimately lead to 1.Rxf7+ as mentioned in Dag's comment above. What follows is one rough path of thought that one might take when facing this position in a game, and some analysis follows below.

Obviously White's queen is attacked, and something must be done about that, so that already cuts down our options considerably. There is a free rook on offer via 1.Qxh8, so what happens if we just take it? The thing to note there is that after the direct 1...Rb5, all three of Black's pieces are bearing down on the white king, while the four white pieces are all unable to help defend. It turns out that to stave off mate there, White would need to shed a losing amount of material. Once one sees this 1...Rb5 threat at all, it's pretty clear that any of 1.Qh2/Qg3/Qf4 leave the queen similarly out of play such that White is unable to defend properly against 1...Rb5.

1.Qe5 is a different case, as it can potentially serve a defensive purpose (supporting Bd5 to nullify the black bishop) and has some bite to it by keeping the queen in the vicinity of the black king. In its favor, Black could no longer respond with 1...Rb5? without the tables turning (see analysis below). Since e5 was the only remaining safe square for the queen, we might feel satisfied with that choice.

But here we should do a little concrete calculating: instead of 1...Rb5?, the move 1...c4 unveils a new attack on the queen and threatens 1...c3; because of that, it's almost game over by that point. But 1.Qe5 seemed like the only place we could put the queen, so we might need to bite the bullet and answer 1...c4 best we can. There the options would be truly limited, and the only way to keep the game going at all from there would be avoiding ...c3 by stirring things up with the desperado sacrifice 2.Rxf7+. (As noted in the analysis, Black actually does need to take care in those complications, and so though this whole approach is objectively not the best from the starting position, it might be a decent practical play.)

With all that laid out, though, we could now at least ask ourselves, what if we try the same complicating idea from the start? The play will be similar to after 1.Qe5 c4 2.Rxf7+, and at this point the only way to decide between that path and 1.Rxf7+ is to bear down and try to calculate the consequences of each (as in the analysis tree below). But note that we're able to get down to these two basic options just by looking a couple of moves deep in combination with a general sense of danger (e.g. our pieces out of play while our opponent's pieces are all attacking). If all goes right in our calculations, we'll find that in fact 1.Rxf7+ gives at least a perpetual (which isn't trivial to work out in full from the start); but again, we're forced into the idea from more general considerations before even getting bogged down in variations.

[FEN "1Q5r/1p2kppp/1q2b3/r1p3P1/p2pB3/P2P3P/1PP1P3/1KR2R2 w - - 0 1"]

1.Rxf7+
    ( 1.Qe5 c4 2.Rxf7+ Kxf7 3.Rf1+ Ke8
        ( 3...Ke7 $2 4.Qxg7+ Kd6 5.Qxh8 c3 6.Qf8+ Kc7 7.Qe7+ Bd7 8.Qb4 $10
        )
    4.Qb8+ Qd8
        ( 4...Kd7 $2 5.Qxh8 c3 6.Qxg7+ Kd6 7.Qf8+ Kc7 8.Qe7+ Bd7 9.Qb4 $10
        )
    5.Qxb7 Qd6 {White has no perpetual, and ultimately the extra black
    rook will tell against the extra white pawns.} )
1...Bxf7
    ( 1...Kxf7 2.Rf1+ Ke7 3.Qxh8 Rb5 4.Qxg7+ Kd6 5.Qf8+ Kd7 6.Rf7+ Bxf7 7.
    Qxf7+ Kc8 8.Qe8+ Kc7 9.Qe7+ Kb8 10.Qe8+ Ka7 11.Ka1 Rxb2 12.Qxa4+ Kb8
    13.Qe8+ Ka7 $10 )
2.Qe5+ Qe6
    ( 2...Kd7 3.Bf5+ $16 )
    ( 2...Be6 3.Qxg7+ Kd6 4.Qxh8 Rb5 5.Qf8+ Kd7 6.Qg7+ $10 )
3.Qc7+ Ke8 4.Qb8+
    ( 4.Qxa5 Qa2# )
4...Kd7 5.Qxb7+ $10 *


Taxicab distance for bishops I have two questions related to defining distances in chess. On this wiki page, this subject is briefly touched, by saying that the taxicab (also called Manhattan) distance is used for rooks, which as shown here, is given by: |a_2-_a_1|+|b_2-b_1| where (a1,b1) is the coordinate of first square, and (a2,b2) that of the second. Now this is easy to see because the chessboard can be mapped to xy coordinate system, with square a1 being (1,1), etc. But for the bishops, it says, that the taxicab distance is again used with the difference of only counting squares of same color and by rotating the chessboard 45 degrees, while using the diagonals as axes now.

Is there a simple formula giving the taxicab distance for bishops similar to that of rooks, using coordinates?
Lastly, the same article mentions the Chebyshev distance (minimum number of moves for the king to go from one square to another), being used for both the kings and queens on board. But knowing the queen moves both like the bishops and rooks, wouldn't a variant of the taxicab distance be more meaningful here?
Any links, or literature suggestions on such ideas (defining distances etc) in chess, would be much appreciated.

It would seem to be max( |a_2-a_1|, |b_2-b_1| ). Whichever of the horizontal or vertical distances is greater, the bishop will always travel over at least that many squares and does not need to travel over any more than that many squares.
This article seems to use distance to mean "number of squares passed over while moving the piece from the source to the destination". In that sense the distance from a1 to c3 for a queen is 2 (Chebyshev distance), not 4 (Manhattan distance); it goes to b2 and then c3, not through b1, c1, and c2.


Where do I play online games with a long time control? I don't have a lot of opportunity to play serious OTB games, so I'd like to play chess online. On chess.com, though, the longest standard time control is 30 min per person, presumably there are not many players wanting to play at longer time controls there. I prefer to have more time, though.

Is there a website where there are enough people willing to play 1 to 1.5 hour (per person) games, so that you are paired within a reasonable amount of time (say, 15 minutes)? (Preferably based on online rating, of course.)

On chess.com, there are at least two groups of people interested in games with long time controls (e.g. 90'+30'' and 45'+45''): the Slow Chess League and the Slow LIVE Chess Association.

They have regular Swiss style tournaments where you have to agree on a date with your opponent under pretty elaborate rules (including penalties for not showing up).

This is not exactly what you asked (random, instantaneous pairing), but probably the better way. The problem with long time controls online is not only finding people who want to play, but discouraging people from losing interest and quitting.

As far as I know, these were founded on ICC when chess.com didn't exist yet. So maybe there is something similar on ICC.


Move my king to check My rook was targeting the opponent's king but her knight was in between
I moved my knight to the check place checked by same knight
Can I move my king to that place

My rook was targeting the opponent's king but her knight was in between

This is what is called an (absolute) pin in chess, i.e. the knight is pinned by the rook and cannot move, because it would put the king in check (which is not allowed).

  I moved my knight to the check place checked by same knight

The way I understand it, what you mean is something like: I moved my knight to a square attacked by the pinned knight. Of course this is perfectly legal as there are no restrictions put on the movement of your knight.

  Can I move my king to that place

No, you cannot move your king to a square attacked by an enemy piece, even if the piece is pinned.

If you think of "winning in chess" as "who captures the enemy king first", all of this makes sense. Specifically, the pinned knight would move first to capture your king, just before you could capture her king (which is now under attack since the knight has moved).

If you search a bit on stackexchange you will find many questions regarding this problem, such as: this question.


Why does Black play Bh3+? This puzzle on chesstempo caught my eye (we play as White):
[FEN "2b2rk/1p3ppp/r/p1p/3pP1Pq/1P1P/P3BPK/1RB1QR2 b - - 0 1"]

1. Bg4

I reckon Black needs to try skewering the rook with the bishop that captured the pawn.
I made a wrong move. It doesn't much matter to the question, yet I wanted to show this nice way Black may mate after my mistake:
[FEN "2b2rk/1p3ppp/r/p1p/3pP1Pq/1P1P/P3BPK/1RB1QR2 b - - 0 1"]

1. Bg4 Bg4
2. Qg4 Kh2
3. Qh4 Kg2
4. Rg6 Kf3
5. Qg4

Anyway, the right move was this:
[FEN "2b2rk/1p3ppp/r/p1p/3pP1Pq/1P1P/P3BPK/1RB1QR2 b - - 0 1"]

1. Bg4 Rh1

I see no point to Bh3+ now, yet Black plays just that and gets the bishop captured:
[FEN "2b2rk/1p3ppp/r/p1p/3pP1Pq/1P1P/P3BPK/1RB1QR2 b - - 0 1"]

1. Bg4 Rh1
2. Bh3+ Rh3

The king protects the rook, therefore it shan't be captured by the queen.
Why does Black play Bh3+?

Black is going to lose the bishop regardless. White is attacking the queen in such a way that it will have to move (or be captured), and there are no available safe squares from which it can continue to protect black's bishop. After the queen retreats, white will be free to capture the bishop with his bishop. By playing Bh3 first, black can at least generate some small counterplay by opening up the file so his rook can come check the white king, while white's bishop remains on a somewhat passive square.


How can I know my rating in chess I play chess sometimes.
I don't know any chess strategy. I just know the direction of each piece.
How can I know my rating?

If you do not play in tournaments, then you do not have a rating. You are unrated.

If you play online, then you will have a rating. However, this is unofficial and cannot be used anywhere else.


Positional thinking by Grandmasters How do Grandmasters think in an unknown position and make the best move?

When a GM, or even lesser strong players reach a position that is totally unfamiliar, they have to break it down into components. They evaluate the following for BOTH sides. In general, a lot of this is done subconsciously by strong players.

Material, and what pieces are better. Sometimes a well-placed knight can be better than a rook, for example.
Can any of the pieces be shut out of play?
King safety.
Are there any direct threats?
Pawn structure and any corresponding weaknesses. (like doubled pawns, but not all doubled pawns are weak or bad as sometimes they provide great protection...more in the endgame can they really be a big problem, but you have to judge this carefully.)
How many pawn islands does each side have? (less is usually better)
Where are the pawn majorities? (Usually a q-side pawn majority is easier to mobilize)
Passed pawns.
Who has more space?
Who better controls the center?
Are there open lines, and who can control them?
Are there half-open files that you can put pressure down?
Strong outposts like being able to put a knight on d6, or a bishop on h6. This can disrupt communication between the two sides of the board, and make defense moving from one side to the other very difficult.
Any colored square weaknesses, like being weak on the light or dark squares.
Any lead in development for either side.
Which trades are good for me, and bad for him? (exchanges are one of the least written about subjects in chess, but they are one of the most important factors in chess as you get stronger. Too bad it has not been translated, but there is a book in Russian called "The Encyclopedia of Exchanges".)
Related to number 16, and that is who has the better endgame if certain trades happen?

Finally, based on these factors, players weigh them based on experience and importance, and then they come up with a list of candidate moves, and they calculate likely continuations.

I might have missed a point, but that is a pretty complete list.


Chess Research Analysis Setup For research purposes, I would like to have a chess engine hooked up to a tablebase where I can be guaranteed that the chess engine is looking at ALL moves and calls the tablebase in real time in small positions. Chess engines may discard some moves on the way to calling the tablebase later, and I need to avoid that, for my purposes. At the very least I have to know that no moves, no matter how silly, have been discarded. Can anyone advise me as to what the best available setup is for this purpose? Or whether some code should be added to an open source engine?

You might find some luck looking to chess problem solvers. In chess compositions, a problem is 'cooked' if it has more than one solution (usually) or any solution that is unintended. If possible, problems are listed as C+ if they are proven by a computer to have only the intended solution(s). Obviously, these solvers do not throw away any moves to make such a proof.

Popeye Solver is one such solver. You can find more information about it on Wikipedia and the web.

You weren't very clear on what you were trying to accomplish though (this would have been important), so I'm not sure if it will work for you or not. Typically, with a program such as popeye it has a position, a stipulation, and a set of conditions. For example, a FEN position, "mate in 5", and "orthodox chess" (or perhaps varying rules).


Take my Queen, Please I find the conclusion of the following game very aesthetic. White could have won by taking in d3 or in f5, but played the cute Qe5, which

sacrifices the Queen,
puts Queens side-by-side (in the middle of the board but not necessarily),
and is the best move (that mates in five).

Do you know any other game with the same pattern?

[fen "5r1k/p1R4p/8/5q2/4Q3/3r4/P5PP/5RK1 w - - 0 1"]
[title "Jozsef Horvath vs Gerhard Adensamer, Dornbirn op (1990)"]

1. Qe5+!! 1-0

Adams - Torre comes to mind. It does not fully answer your requirements - some sacs are not side by side, some are not in the middle of the board - but still...

[fen "2r1r1k1/1p1q1ppp/3p1b2/p2P4/3Q4/5N2/PP2RPPP/4R1K1 w - - 1 0"]

1. Qg4 Qb5
2. Qc4 Qd7
3. Qc7 Qb5
4. a4 Qa4
5. Re4 Qb5
6. Qb7 1-0


How to play against the inverted Philidor opening with Black I was playing with the Black pieces online today, and faced a very strange opening:
[fen ""]
1. e4 e5 2. Nf3 Nc6 3. d3 Nf6 4. Be2

I check the database, and it seems that 4...d5 is good for black but I didn't understand the strategy behind it at all. Here are a few moves from the database:
[fen ""]
1. e4 e5 2. Nf3 Nc6 3. d3 Nf6 4. Be2 d5 5. Nbd2 Bc5 6. O-O O-O 7. c3 a5 8. Qc2 Re8 9. b3

I don't understand what Black is playing for here. Like what the plans are. I would really appreciate some feedback or references where I can read more about it. My understanding is that the Black pieces look like a position from an Italian opening. But I felt that the Italian plans don't work here tactically (like maneuvering Nc6-e7-g6).
I'm also open to other suggestions, such as playing 5...g6 (but I also didn't understand the plans behind it in this position).

The basic idea with ...d5, ...Bc5 is just to gain some centre space. I wouldn't really compare this position's plans to the Italian, as they're not that similar. Black's pushed ...d5 early on, and the opponent's (White) knight is on d2 instead of c3.
Analysis for 8.b3: one move for Black in the database is 8...Re8 (or 8...Qe7), supporting the e5-pawn. Now playing ...d4 is an idea, since cxd4 can be answered with ...Nxd4 (as the e5-pawn won't hang). In the case of 9.Bb2, 9...Bb6 10.Re1 Bg4 11.Qc2 Qd6 looks nice for Black. Pushing ...d4 at some point is still in the cards. Black could also consider some ...Qc5 move, pinning the c3-pawn and targeting the f2-pawn. Adding more pressure on the d-file with ...Rad8 looks reasonable.
Analysis for 8.Qc2: 8...Re8 9.b3 could be met with 9...Ba7 (or 9...Bb6), preventing White's queen from x-raying the bishop. This makes ...d4 safer to play. After 10.Bb2 h6 (stopping Ng5 if Black decides to play ...Be6 at some point) 11.Rfe1 Qd6 12.Bf1 Bg4, we have a similar position to what was reached for the line looked at in 8.b3. The plans are similar to what they were there.


Where can I find a rarity table of chess player ratings? Now it's fine either as percentage of all FIDE players registered or just as number itself (like either 1/100k players are rated above X, or 23 players rated above X, respectively).  Let's say by their peak rating and not necessarily current one.

If unclear what I mean, let's take an example: Last time I checked there were 10 players who reached a rating of over 2800 ELO at some point in their career.  I don't know how many FIDE players there are, but if, say, a million, then rarity here is 10/1,000,000.  Or we could simply use the number 10.

Now I'm looking for something similar but in a table, like with +2700, +2600, and all the way down.  Do you think such information is available?  Thanks.

edit: I wanted specific numbers which the other thread had not provided. I am happy with the answer I've chosen now.

According to the list downloaded here, there are currently 261782 players with a FIDE rating. I wrote a small program to analyze it, and here are the results:

-------------------------
Rating  Number of players
2800+   5
2750+   18
2700+   43
2650+   114
2600+   262
2550+   514
2500+   921
2450+   1641
2400+   3130
2350+   5223
2300+   8669
2250+   13791
2200+   21033
2150+   30045
2100+   41411
2050+   54631
2000+   69229
1950+   83243
1900+   97932
1850+   112783
1800+   127483
1750+   141826
1700+   155776
1650+   168856
1600+   180987
1550+   192154
1500+   202332

Keep in mind that there are a lot of countries where club level players (1500 - 2000) have a national rating but not a FIDE rating.

For reference, here is the Java program I wrote. Feel free to modify it for your own analysis.

public static void main(String[] args) throws Exception {
    BufferedReader reader = new BufferedReader(new FileReader("rating.txt"));
    String line;
    int[] frequencies = new int[3000];
    boolean first = true;
    while ((line = reader.readLine()) != null) {
        if (first) {
            first = false;
            continue;
        }

        frequencies[Integer.valueOf(line.substring(113, 117))]++;
    }

    int total = 0;
    for (int rating = 3000 - 1; rating >= 0; rating--) {
        total += frequencies[rating];
        if (rating % 50 == 0) {
            System.out.println(rating + "+\t" + total);
        }
    }
}


What is a chess database used for? I frequently see advice about how to learn chess that include links to databases, or how to set them up, or a question here about Analysis where the accepted answer says to just add some stuff to your database.

But what is that database, really? I never saw an explanation for that.

And how would a beginner use a database? Why does everyone talk about databases but never explain what they are in first place?

I assume they are important, since seemingly there are lots of companies that get lots of money solely by selling chess databases...

what is that database, really?

A chess database is basically a collection of chess games, i.e. a collection of moves with metadata such as player names, date, Elo rating of players, place, opening name ... It can also include comments/annotations for some or all games.

There are various websites such as lichess, chesstempo, 365chess where you can access chess databases for free. Alternatively you can download database files from the internet or buy them from somewhere like ChessBase and access them on your computer. For this you need a program/application such as Scid (free) or ChessBase (not free) which can read the database files and allows you to play through the games and do all kinds of searches/manipulations to the database files.

Also you can of course manually add your (or anybody else's) games to the database.

how a beginner use a database?

You don't, really. As a beginner you should focus on learning general principles of playing chess and studying tactics. You don't really need a database for either.

How can a database be used?

Databases are immensely useful for studying openings. They allow you to keep all the variations/sidelines nicely ordered, you can add comments to moves, you can see which line is the most popular, which line has the highest winning percentage (or which line is more drawish, which more risky...), you can filter games (e.g. show only recent, or only games of high rated players or only white wins, or only a certain variation...). Based on this you can build an opening repertoire (which you could save in a separate database) and/or expand your opening knowledge. Also chess database software works well together with chess engines which gives you further possibilities for study. Unlike books, a database can always updated (e.g. from twic), so you always have the latest developments in opening theory at hand.
You can also use the database to study middle- or endgame plans. For instance you can search the database for specific positions and/or material distributions and then see how a grandmaster plays these positions.
You can prepare for a game against an opponent by studying his/her games beforehand (assuming there are games of your opponent in the database) looking for weaknesses in the opening repertoire or weaknesses in playing certain types of positions.
You could use it to follow your favorite chess player's games just for fun.


ICCF rule for analyzing position with another human I do know for certain that on ICCF engines are allowed, but the question is whether analyzing the position with a human is allowed? I know that on chess.com if you let someone play on your profile you will get banned. The reason is that if it's allowed I am planning to post a question regarding my current position on a game on the ICCF.

Yes, it is legal.

ICCF: Says nothing about it, or assistance of any kind, and you can even use computers legally. Here are their rules.

USCF: "3. You may consult chess books and periodicals but not other players." Here are their rules.

With regards to the ICCF rules, my guess is that they just decided it was too hard to police computer used, so they just allow it. Books have always been permitted. Human assistance also.


What is the record for the most pawns, of both sides, on a file in a professional chess game? Some of us have heard about the famous game Kovacs-Barth, Balatonbereny 1994, which has the longest known surviving quadrupled pawn structure . It is one of many games with quadrupled pawns for one side, since quintupled hasn’t occurred yet. However, when it comes to counting pawns of both sides, has a higher number been reached? Hextupled pawns are the obvious limit, but it is a matter of finding such a game.

I did some searching on Tim Krabbe's site and, in Journal Entry #278, I found that Krabbe gave a unique game in which there are 6 pawns on the c-file, 3 per side, on move 21! This is the obviously the maximum.
[Title "Sevcikova-Blichova, ch girls u12, Slovakia, 1999"]
[FEN ""]
[startply "42"]

1. e4 e5 2. Nf3 Nf6 3. Nc3 Nc6 4. Bb5 Bb4 5. a3 Bxc3 6. dxc3 Nxe4 7. Bxc6 dxc6 8. Qxd8+ Kxd8 9. Nxe5 Rf8 10. O-O Bf5 11. Be3 Nd6 12. Rac1 Re8 13. Rfe1 f6 14. Nd3 Nc4 15. Rcd1 Ke7 16. Bxa7+ Kf7 17. Bc5 Rxe1+ 18. Rxe1 Re8 19. Rxe8 Kxe8 20. b3 b6 21. bxc4 bxc5 22. a4 Bxd3 23. cxd3 Kd7 24. a5 Kc8 25. f4 Kb7 26. g4 Ka6 27. Kf2 g5 28. fxg5 fxg5 29. Kf3 Kxa5 30. d4 Kb6 31. d5 cxd5 32. cxd5 c6 33. d6 Kb7 34. Ke4 Kc8 35. Kf5 Kd7 36. Kxg5 Kxd6 37. Kh6 Kd5 38. Kxh7 Kc4 39. g5 Kxc3 40. g6 c4 41. g7 Kb2 42. g8=Q c3 43. Qb8+ Kc2 44. Kg6 Kd2 45. Qd6+ Kc2 46. Qxc6 Kd2 47. Qd5+ Kc2 48. h4 Kb2 49. Qb5+ Ka1 50. h5 c2 51. Qc5 Kb1 52. h6 c1=Q 53. Qxc1+ 1-0

For one side, the recuring record is four, as shared by many. There is no known case of quintupled pawns yet, for which the stars must align. However, as mentioned, the most notable example is the game in which the structure survived an astonishing 23 moves.
[Title "Gabor M Kovacs-Rainer Barth, Balatonbereny Open, 1994"]
[FEN ""]
[startply "43"]

1. e4 Nf6 2. Nc3 d5 3. exd5 Nxd5 4. Bc4 c6 5. d4 g6 6. Nge2 Be6 7. Bb3 Nxc3 8. bxc3 Bxb3 9. axb3 Bg7 10. O-O O-O 11. f4 Na6 12. Ba3 Re8 13. Qd3 Qb6 14. f5 c5 15. fxg6 fxg6 16. Qc4+ e6 17. dxc5 Qc6 18. Rad1 b5 19. Nd4 Qxg2+ 20. Kxg2 bxc4 21. Nb5 Reb8 22. bxc4 Rc8 23. Nd6 Rc6 24. Ne4 Rac8 25. Rd7 R6c7 26. Rd6 Rc6 27. Rfd1 Bf8 28. Rxc6 Rxc6 29. Rd8 Kf7 30. Rd7+ Be7 31. Rxa7 h6 32. Bc1 g5 33. h4 gxh4 34. Bf4 e5 35. Bxe5 Re6 36. Nd6+ Kg6 37. Bd4 Nb8 38. Ra8 Nc6 39. Rg8+ Kh5  40. Nf5 Rg6+ 41. Rxg6 Kxg6 42. Nxe7+ Nxe7 43. Kh3 Nc6 44. Kxh4

Interestingly, the 6 pawns game is an example of 2+1, 2+2, and 2+3 pawn structures. I wondered if 3+1 had ever occurred, and I found such an example. It occurs on move 10, although faster has surely been done.
[Title "Jorn Sloth-Grigory Sanakoev, CORR, 1992"]
[FEN ""]
[startply "20"]

1. c4 Nf6 2. Nc3 e5 3. Nf3 Nc6 4. e3 Bb4 5. Qc2 O-O 6. Nd5 Re87. Qf5 d6 8. Nxf6+ gxf6 9. Qh5 e4 10. a3 exf3 11. axb4 Nxb4 12. Ra4 Re5 13. Qh6 fxg2 14. Rg1 Bg4 15. Rxb4 gxf1=Q+ 16. Kxf1 Rg5 17. Rg3 Rg6 18. Qf4 Qd7 19. f3 c5 20. Rb5 Bf5 21. e4 Be6 22. d3 f5 23. b4 b6 24. Bb2 f6 25. Kg1 Rf8 26. Ba1 Kf7 27. Bc3 Kg8 28. Qh6 fxe4 29. Rxg6+ hxg6 30. Qxg6+ Qg7 31. Qxg7+ Kxg7 32. bxc5 dxc5 33. fxe4 Rd8 34. Rb3 Kg6 35. Bb2 f5 36. Kf2 fxe4 37. Ke3 exd3 38. Rxd3 Re8 39. Kf4 Bxc4 40. Rg3+ Kf7 41. Rg7+ Ke6 42. Rxa7 Kd5 43. Rd7+ Kc6 44. Rd2 b5 45. h4 Bf7 46. Be5 b4 47. Rd6+ Kb5 48. Rd7 Bg6 49. Rb7+ Kc4 50. Rb6 Bh5 51. Rh6 Be2 52. h5 Rf8+ 53. Kg5 Bd3

This leaves 4+1 and 4+2 pawn structures are still yet to known to me. 4+1 has probably occurred, but I severely doubt the existence of a 4+2.
Lastly, here is a game in which tripled pawns occur on move 7. However, the actual record may be 6 moves, if not 5.
[Title "Gerhard Kiefer-Peter Krauseneck, Bundesliga Germnay, 1982"]
[FEN ""]
[startply "13"]

1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. dxc5 Qc7 6. Nf3 Bxc3+ 7. bxc3 Qxc5 8. Bd3 Nc6 9. O-O Nge7 10. Rb1 Qxc3 11. Rb5 Nd4 12. Nxd4 Qxd4 13. Rxb7 Qxe5 14. Bb2 Qd6 15. Rb3 f6 16. Qh5+ Kf8 17. c4 dxc4 18. Bxc4 Qc6 19. Bb


How can I speed up my check detection in Javascript? I am trying to write a simple chess engine in Javascript. It performs very slowly but I have finally rooted down the problem to check detection. How might I speed up this check detection? If you have any questions or need any clarifications feel free to ask.

Check detection takes approximately 10-20 milliseconds.

Here is the code:

function availableInvalidSpots(board, player) {
    let validPositions = [];
    let playerPositions = getAllPieces(player, board);
    for (position = 0; position < playerPositions.length; position++) {
        validPositions.push(getUncheckedMoves(playerPositions[position], board));
    }
    return validPositions;
}

function getPiecePosition(piece, board) {
    for (rowCount = 0; rowCount < 8; rowCount++) {
        for (columnCount = 0; columnCount < 8; columnCount++) {
            if (board[rowCount][columnCount].pieceName == piece) {
                return {
                    x: columnCount,
                    y: rowCount
                };
            }
        }
    }
}

function getPlayerInfo(pieceType) {
    return (pieceType == blackPieces ? {
        king: "blackKing",
        opponent: whitePieces
    } : {
        king: "whiteKing",
        opponent: blackPieces
    });
}

function setPlayerInfo(player, board) {
    let PLAYER = getPlayerInfo(player);
    let opponent = PLAYER.opponent;
    king = PLAYER.king;
    kingPosition = getPiecePosition(king, board);
    opponentMoves = availableInvalidSpots(board, opponent);
}

function isPlayerInCheck(player, board) {
    setPlayerInfo(player, board);

    for (opponentMove = 0; opponentMove < opponentMoves.length; opponentMove++) {
        for (square = 0; square < opponentMoves[opponentMove].move.length; square++) {
            if (opponentMoves[opponentMove].move[square].to.x == kingPosition.x && opponentMoves[opponentMove].move[square].to.y == kingPosition.y) {
                return true;
            }
        }
    }
    return false;
}

It looks like your engine is using very simple for loop and arrays. Your code simply loop over again and again, possibly repeat each search iteration.

That’s obviously not good. Chess engine can’t run fast if it has to loop like that. If the position had no check surely all CPU time wasted?

My recommendation is change your data structure to a bitboard. Bitboard will allow you run check detection quickly, just do a AND the pieces your opponent can attack and your king position.


How do I determine the bye player in a given round of a round-robin tournament? The Berger tables for round-robin tournaments state:

  Where there is an odd number of players, the highest number counts as a bye.

As far as I understand this statement correctly, this means that, for example, in an 8-player round-robin, the 8th seeded player will always be the bye player and hence will not play any game.

What else could this mean?

It means that in the pairings given in the tables, if there are an odd number of players (so not an 8-person round-robin for instance), the player playing against the highest number receives a bye.

For instance, for 5 players (use the 5-6 player table):

Round 1: #1 gets a bye
Round 2: #4 gets a bye
Round 3: #2 gets a bye
Round 4: #5 gets a bye
Round 5: #3 gets a bye


Is it technically a checkmate if the king is not in check, but all moves will result in check? In other words, after white's move, black king is not in check.  It is now black's move, but any move that black could make results in check.  Is this a checkmate?  Is there a chess term for this situation?

Putting your king in check is not a legal move as you've realized.
Of course, if Black has any OTHER legal moves he can and should play one of them!
If a side TO MOVE does not have ANY legal moves, that would be a stalemate, not a checkmate (which is delivered only by the side making the check)