Can someone explain this computer suggestion to me? [FEN ""]

1. d4 d5 2. c4 dxc4 3. Nf3 e5 4. Nxe5 c5 5. d5 f6 6. Nxc4 b5 7. Nca3 c4 8. Nxb5 Qa5+ 9. N1c3 Bb4 10. Nd4 Bxc3+ 11. Bd2 Bxd2+ 12. Qxd2 Qxd5 13. Rc1 Nh6 14. b3 Nf5 15. bxc4 Qxd4 16. Qxd4 Nxd4 17. g3 Bb7 18. Rg1 O-O 19. e3 Nf3+

In this game, I tried to play the Catalan opening as white, but black didn't go along with it.  Early on I took free pawns (if you think this was mistake, please let me know).

Anyways, the move in question is 11. Bd2.  The computer suggests 11. bxc3, but if I do that, can’t black play Qc3+ and then take my rook?  Or would Bd2 be the appropriate response to Qc3+? It all went down hill for me after this, so I am thinking that I need to learn about this pivotal point.

Well, you were winning handily, and up material, and position. The move Nd4?? blundered a piece, and Bd2 actually makes it clearly worse, which is why the computer liked bxc3. Given two clear choices (that is, not two 0.00 or equivalent), the computer will always pick the one with the higher evaluation, and it did. Here is why it evaluated it as such.

The idea of Qd2, allowing Qxa1 is common because the queen is so out of play. Often, white has a pawn on d4, and there is no pawn on c4 for black, so Nb3 would trap the queen immediately in some similar positions.

The line after Qd2 is a tactical mess, which had it been reached by normal means (one side not losing material early), it probably could fill at least a chapter in a book. I will give a couple of lines, but there were SO many more along the way. There may be improvements for black along the way, but at the very least, despite being up a whole rook, it is actually much more dangerous for black with threats to both the king and queen.

Again, in short, the computer saw a way of keeping the black queen out of the game, and thus, it liked that line better because white may actually be significantly better in all lines, but it is hard to prove. Black is hanging by a thread. The other way was just a really bad game after Bxd2 Qxd2 Qxd2, so the choice to the computer was easy.

It is also worth noting that the black pieces, like the rooks a8 and h8 were also out-of play, and black was behind in development.

 [FEN ""]

 1. d4 d5 2. c4 dxc4 3. Nf3 e5 $4 4. Nxe5 $16 c5 5. d5 f6 6. Nxc4 $18 b5 7. Nca3 c4 $4 8. Nxb5 Qa5+ 9. N1c3 Bb4 10. Nd4 $4 {Losing a piece.} (10. a3 {Your chance to force the Bb4 to make a decision.} Qxb5 (10... Bxc3+ 11. Nxc3 $18) (10... Bc5 11. Bf4 $18) 11. axb4 Qxb4 12. Ra4) 10... Bxc3+ 11. Bd2 (11. bxc3 $1 Qxc3+ 12. Qd2 $1 Qxa1 13. g3 {This is just a better way to give back some of the material. It is very deep, but it almost wins the queen, but in saving it, the king comes under a strong attack because it is stuck in the center.} Nd7 {I will play the best computer moves here...others are worse.} (13... c3 14. Qc2 Na6 15. Nb3 $18) 14. Bg2 Rb8 15. O-O Ne7 (15... Qb1 16. Qe3+ $18) 16. d6 Ng6 17. Be4 Nc5 {The only move along with Rb1.} (17... Rb1 18. Ne6 Nb6 19. Nxg7+ Kf7 20. Qh6 f5 21. Bxb1 Qxg7 22. Qxg7+ Kxg7 23. Bb2+ Kf7 24. Bxh8 Nxh8 $16) 18. Bd5 Bd7 19. Qe3+ Kf8 20. Ba3 Rb1 21. Rxb1 Qxb1+ 22. Kg2 Ne5 23. Bxc5 g5 {Only move.} 24. h4 h6 25. Ne6+ Bxe6 26. Bxe6 Kg7 27. Bb4 $3 Qxb4 (27... Ra8 28. a3 a5 29. Bd5 Rf8 30. Qa7+ Nf7 31. Bxa5 $18) 28. Qxa7+ {Mating.}) 11... Bxd2+ 12. Qxd2 Qxd5 (12... Qxd2+ $1 13. Kxd2 f5 $1 {And Nf6 is strong.}) 13. Rc1 (13. e4 $3 {This almost impossible-to-find move was the ONLY move here, but black retains some advantage.} Qd6 (13... Qxe4+ 14. Be2 $1 {And the h1-a8 diagonal is going to win material for white, or compromise the black king position.} Nc6 {Only move.} (14... Qxg2 $4 15. Bf3 $18) 15. Nxc6 Qxc6 16. Bh5+ g6 17. Bf3 Qe6+ 18. Kd1 $16 {With the dual threats of Re1 and Bxa8.}) 14. Bxc4 Ne7 15. Rc1 Bd7 $15)


What to do when your opponent doesn't play along in the opening? I looked around and could not find an answer for this.

I've studied a pretty good amount of opening theory and so I know the "correct" moves for some basic lines.  Most e4 openings and a fair amount of Nimzo-Indian, Pirc, and QGD for D4.

The thing of it is, I often play opponents who have not studied these lines.  So they play the "wrong" moves and I'm not sure how to proceed.

Is it best for me to stop and eat clock time figuring out why the wrong move is wrong?  Or should I keep playing my same opening even though I might be putting myself deeper into a hole?

It sounds like you're a beginner. As such, you should be focusing more on tactics than openings.

First, just because they play a move that's not in your book, doesn't mean it's "wrong". It may be an older line that's not in modern opening books, or just not in the books you have.

That being said, to answer your question, it depends on the opening. In a slow, closed or positional openings, it's not likely to matter too much, when your opponent deviates from your book, just adjust your plans as necessary. If it's a gambit, or tactical opening, you should take some time to check to see if it's a blunder.


Beginner book that has endgame scenarios I’ve been looking for free online books on endgame scenarios, since I'm very bad at them. So far, I haven’t gotten any luck.
By the way, I only know the pieces moves and some other basic stuff.

BCE (Basic Chess Endings) by Fine was the one I used.  It is long out of print.  There are some  newer books but I can't say which of them might be good now.  Also online has the sort of info you want and would be easier to find what you think is good for you.


What is the shortest possible legal game where there are 6 pawns on the a-file or h-file? I was recently reading a post on this forum which said that there must be 15 captured pieces in order for there to be 6 pawns on the a-file or h-file.
That got me thinking how complicated that would be, which got me thinking how many moves would it take for such a thing to happen.
So, what is the minimum length of a legal game (i.e. reachable from starting position) where there are 6 pawns of the same color on either the a-file or h-file?

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

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

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

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

Source: The Die Schwalbe Chess Problem Database


Why does White play Nc4? I was solving some problems on chesstempo. This one caught my eye (the White just played Ng2, we play as the Black):
[FEN "1k5r/pp4p/5b1p/qPP/N2r1p/P4P/K1Q3PP/2R3R w - - 0 1"]

1. Nb2

I saw that the right move was Rd2, yet I failed to foresee White's play.
I reckoned the best move for the White to be Qb1:
[FEN "1k5r/pp4p/5b1p/qPP/N2r1p/P4P/K1Q3PP/2R3R w - - 0 1"]

1. Nb2 Rd2
2. Qb1 Rb2
3. Qb2 Bb2
4. Kb2

I might be missing some moves playing as black, yet it still seems to me that White wins more material playing Qb1 instead of what appeared to be the solution:
[FEN "1k5r/pp4p/5b1p/qPP/N2r1p/P4P/K1Q3PP/2R3R w - - 0 1"]

1. Nb2 Rd2
2. Nc4 Rc2
3. Rc2

Why did White play Nc4, not Qb1? What am I missing? I can't see any forks or something, which would justify the attack on the Queen.

it still seems to me that White wins more material playing Qb1 instead
of what appeared to be the solution

No, if you compare the two final positions the only difference is that in the Nc4 line white has an extra knight and black has an extra bishop, so no difference if you are counting points.

Why did White play Nc4, not Qb1? What am I missing?

Good question!
Both final positions are completely lost for white. The only practical difference is that in the Nc4 line the extra piece for either side creates more possibilities for white to try and create something. Black has more work to do to get the full point. In particular the knight can land on d6 where it is a very good piece.
Another significant point is that in the Qb1 line in the final position Qxb5 comes with check and tempo whereas in the Nc4 line Qxb5 is not check.
Small points perhaps but noting them helps you build your ability to fight on in lost positions.


Why is 7...Ne4 8.Bd2 such a popular line in this variation of the Queen's Indian Defence? This is the opening I'm referring to:

[fen ""]
1.d4 Nf6 2.Nf3 e6 3.g3 b6 4.Bg2 Bb7 5.O-O Be7 6.c4 O-O 7.Nc3 Ne4 8.Bd2!?

The other white book moves at this point seem sensible 8.Qc2 or 8.Qd3, or even  8.Nxe4 (which seems to almost always draw).  I'm unsure about 8.Bd2, as it seems to give up the bishop pair (and 8...Nxd2 has been played, e.g., Gelfand vs. Radjabov, 2017) and it puts the bishop on a fairly modest square, but it's listed as having 1500+ master games at LiChess.

Question: Why is 7...Ne4 8.Bd2 such a popular line in this variation of the Queen's Indian Defence?

The most popular continuation on LiChess is the following:

[fen ""]
1.d4 Nf6 2.Nf3 e6 3.g3 b6 4.Bg2 Bb7 5.O-O Be7 6.c4 O-O 7.Nc3 Ne4 8.Bd2 f5 9.d5 Bf6 10.Rc1 Na6 11.a3 Nac5 12.b4 Nxc3 13.Bxc3 Ne4 14. Bxf6 Qxf6

White wants to avoid doubled c-pawns and all of the moves you mention, Qc2, Qd3, Nxe4 and Bd2 achieve this.

As you note, Nxe4, exchanging knights tends to be drawish, so is not what most white players want.

With the queen moves (Qc2, Qd3) your queen will end up on c3, which is a bit of an unusual square for the queen. Also the c1-bishop is not developed yet, so white would still have to connect his rooks and likely move the queen to a better square.

Bd2 is a modest development move for the bishop, but it does make space for the rooks. Also, if black takes Nxc3, Bxc3 and the bishop has found a very nice square on c3.

I would not be concerned about giving up the bishop pair. The black knight on e4 is a rather strong piece while the dark squared bishop is the weaker of white's bishops due to the pawn structure.


What to put in a personal chess database? I was thinking about creating a personalized chess database for my correspondence chess play. What sorts of contents are useful to put in it and is there any big difference in having your own database versus just using one from online. The main factor that contributed me to do this was to deepen my opening knowledge of certain openings. I am open to any other reasons why I should or shouldn't create one.

For correspondence I keep a database of my personal opening book that I extend whenever I encounter a new move.  I include notes on things like why I chose a particular line and both numeric and verbal position assessment.  I also include select text from books or other databases that discuss that position.


Open source chess playing or pgn viewing libraries Is anyone familiar with any open source chess libraries in any language that can do any of the following:

parse PGNs and/or FENs
calculate valid chess moves based on position
process an entire chess game

EDIT:

Sorry, I should be more clear. I'm not looking for open source software, I'm looking for open source programming libraries.

Crafty

Crafty is a strong chess programm and can be used with Winboard, Xboard and Scid. So it is available for all major operating systems.

Scid

Scid can maintain databases of chess games, you can analyse (end) games.The software is available for all major operating systems.

Xboard

Xboard is a user interface to the Internet Chess Server. It uses the X Windows System, so I assume this runs only under GNU/Linux. Xboard can be used as a viewer and supports all forms of chess.


How to improve positional play while keeping the initiative? I consider myself an advanced beginner in the 1400-1500 range. I play for fun, like to do tactics and I try to understand instead of memorizing openings and such.

I've been analyzing some grandmaster games and realized that improving the position of pieces is a critical part of chess. I usually develop pieces pretty quickly and launch attacks as soon as I have  a bit of tempo. I often see weaknesses in my position but I fear that if I stop the attack I'll lose tempo and it'll backfire on me. Sometimes if the game is very closed, I'll try to break through first by sacrificing and gaining some tempo but I feel I should be making sure that every piece is at an optimal position before breaking in. The thing is, I want to make I dictate the game, not the other way around.

How would you recommend that I improve my positional play while keeping in mind tempo? I can think of putting pressure on pieces as being on, but what about pawn development? Moving my knight 3-4 times to put it on a better square? These seem to take too much time, and I realize I am in the wrong here.

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

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

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

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

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

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

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

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

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


Usefullness of analysing ones own games with an engine There are different opinions on analysing your games with an engine. Some say you shouldn't use an engine at all, and others say you can use it, but you should do your own analysis first. Most say that you shouldn't use the engine without a manual analysis first.

But what can you learn from an engine analysis? They can point out tactical mistakes, but if the mistakes imply you must correctly play a long variation, and you don't manage this, the whole variation fails. But of course, often the mistakes are easy to see. But I have started to ask myself, how valuable is this at pointing out tactical mistakes? Often I can find the easy mistakes by myself, and the hard ones are probably above my understanding.

Maybe the engine is more useful for endgame? But even so, it can be hard to understand the engine moves.

For the opening I think an opening-db or opening books are much better then the engine.

The best option is to probably analyse games with a stronger player/coach, but I do not have that option. You can also try to get help from players on sites, asking for help with analysis. I have tried this on chess.com several times, but I have gotten very few answers. I am trying Chess Stack Exchange to see if I get more responses.

I found this article that has lots of good advice.

First of all it kind of depends on your playing strength, but every player can benefit at least a bit from an engine.

Personally I use the engine for the following analysis:

Opening preperation: I play out different variations of my opening with the engine running. I do this so I dont miss any critical good moves of my opponents. For myself I dont necessarily chose the best engine move, but the move I think fits my style the best. At the end I check if I like the position and what the engine says of it. I dont care about +- 0.2, as long as I feel the position is good for me.
Open issue control: If I play 10+0 or 15+15 online, I dont analyze every game by hand afterwards. But I will go for a quick engine run and check, what kind of mistakes I made (if there are any). This way, I get a overview about my typical mistakes and know where I can improve. I also check, if I followed my prepared opening ideas (if present) and how the position developed.
For club games, I will always first analyze them by hand. The time spent depends a lot about the position and how many ideas I find which are worth analyzing (or ideas I had in the game but could not calculate due to time). Of course I will analyze my mistakes I spot myself. Afterwards I will run the engine and check if I missed any mistakes. In addition I will play out some lines of the engine which I find intresting. Afterwards I think about, wheither I could have spotted it during the game and if it was something I could play myself, regarding the resulting position.

In general, I think an engine gives you intresting insights, but you should always remember, that you dont have to be able to play like the engine. So the engine will find some lines, which you should dismiss, because they are too hard for you.

For additional benefit, you can use a book to improve. I will sit down with a chess book go over some content and later on use the engine to double check the ideas I learned in the book.


How does one know if a position is not reachable from a series of legal moves from the starting position? If one of the following is true, a position is not reachable from the starting position by a series of legal moves:

One side has two or more kings or one side has no kings;
One side has  a total of 10 or more queens and pawns, or a total of 11 or more rooks and pawns, or a total of 11 or more knights and pawns, or a total of 10 or more bishops of the same colour and pawns;
One side has a total number of more than 16 pieces;
At least one pawn is in the first rank or eighth rank;
Both kings are being checked;
The kings can capture each other in the next move;
At least one bishop is in an "impossible square" blocked by pawns in their starting positions, such as the following:

One king is being "impossibly" checked or checkmated such as the following (this should also include the case where a king is being checked by three or more pieces): (I am not sure how to define this more precisely);

One side is checking and it is his turn.

I am sure that this list is not exhaustive. Does one know a complete list? Is there an algorithm determing whether a position is reachable from the starting position by a series of legal moves?

Edit: I would also add the following:

One side has more than 8 pawns.

Here is a retro which needs deep analysis:

[Title "Thierry le Gleuher; Economy Records in Add Unit(s) Problems, 5A"]
[StartFlipped "0"]
[fen "B5bn/5PrR/5prN/6pk/7p/5P2/PPPPPP2/KR1Q2N1 w KQkq - 0 1"]

The stipulation is "Add the missing unit(s)". A solution may be found in entry P1227636 in PDB. In brief:

   To disentangle Black's kingside, White must retract most pieces back home so that White can retract g2xf3. Interleaved with these White moves are 19 Black moves. But, all this time, Black has no retrotempi with units in the diagram, so they must be provided by the added units. The only way is to add black pawns on a3, b3, c3, d3, e3. Each provides 4 retrotempi, except that the b and d pawns can't both retract home, because the bishop on g8 will need to retract to c8 eventually.

Thus the position would be illegal if

   5 black pawns were added but any of them were nearer rank 7, because Black would run out of retrotempi, but it would take deep analysis to show that this is the case.

This might be the sort of situation RemcoGerlich was thinking of, seeing that

   Some White pieces need to leave the back rank and move back in a different order.

In case you thought that there's a simpler way to add units:

   A Black piece captured White's c1 bishop on c1. White is not missing anything else, so no Black pawn ever left its file. Thus White's 3 captures g2xf3 and hxgxf were of Black's 3 missing pieces: the f8 bishop, the queen and a knight. So we may add Black pawns but not a piece.


Does Magnus Carlsen have any openings/opening variations named for him? Does Magnus Carlsen have any openings/opening variations named for him?

The last world champion I know of to have an opening variation named for him was Anatoly Karpov (e.g. Caro-Kann, Karpov Variation or Karpov Variation in the Ruy Lopez).

In the old days variations were named after players who did serious theoretical work and/or played one line consistently over a longer period.

As openings got more and more analyzed it got increasingly more difficult to find new variations comparable to those old masters. Nowadays the top players might find a novelty around move 20 or so. If you want, you could call those lines variation and credit them to the player. I am sure some websites do just that, but personally I see a big difference between say the Najdorf variation and those side lines.

So yes, probably somebody somewhere called something a Carlsen variation, but whether you consider it a variation is up to you. Also, perhaps it needs some more time until a line is called variation and maybe in 10 years people will agree to call a line Carlsen variation.


How do you win with a queen against a rook? What's the technique behind the moves of the stronger side in order to win?

Are there situations where the side with K+R can force a draw against K+Q?

I've read plenty of examples of K+Q vs K+R, but they were only mere sequences of moves without explanation, and sometimes I didn't get the logic. The only thing I managed to understand is that the stronger side has to force the Rook away from his King, and then double-attack them with the Queen. But how can I make it happen?

There are several key positions from which it is easy to memorize the win. The basic idea is to drive the opposing king to the edge of the board, and then to the corner, where you can force the rook to separate from the king.

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "King and Queen"]
[Black "King and Rook"]
[Result "*"]
[SetUp "1"]
[FEN "8/6rk/5K2/3Q4/8/8/8/8 w - - 0 0"]
[PlyCount "11"]

1. Qh1+ (1. Qh5+? Kg8 {this is the diagram we want, but the wrong side has the
move.}) 1... Kg8 2. Qh5 {This is the key position to have with black to move.
The rook must leave the king} Rg1 (2... Kf8? 3.Qh6) 3. Qd5+ Kh7 4. Qe4+ Kg8 5. Qa8+ Kh7 6. Qa7+ {
forks the king and rook} *

The first move in the diagram is Qh1+. Qh5+? is a mistake, though the position is the one we want the wrong side is to move.

After 2.Qh5 we have the position we want. The rook must leave the protection of the king, and a series of checks will allow a fork of king and rook by the queen.

If the rook is already separated, then there is usually a sequence of checks that produce the win.

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "King and Queen"]
[Black "King and Rook"]
[Result "*"]
[SetUp "1"]
[FEN "8/8/8/4K3/r6k/8/3Q4/8 w - - 0 3"]
[PlyCount "9"]

3. Kf5 Kg3 4. Qd3+ Kh4 5. Qc2 Ra5+ 6. Kf4 Kh3 7. Qc3+ *


What is the best line of the Colle to play against KID set up by Black? Playing the Colle, if Black plays g6 and then Bg7 what is the best line for White?

The English GM Simon Williams has just tweeted this -

  Just finished filming 'The Colle' a DVD for @ChessBase. I must say
  that the Colle with 1 d4 2 Nf3 3 e3 4 c3 5 Nd2 and 6 Bd3 is basically
  rubbish. But the 'Colle-Zukertort' with 4 b3 is another matter
  entirely... Learnt a lot filming this week.

That sounds reasonable to me. In other words you are wasting your time.

In general the answer to the question "Given that I always play opening X how should I use opening X to reply to opening Y by my opponent?" is nearly always something along the lines of - "You should not dogmatically play opening X in all circumstances. You should always play the position in front of you and try and find the best moves. If your opponent plays something against which your standard opening is rubbish then play something else."

Against the KID the Colle is a silly opening to play. The same could probably be said of the London. Classical lines involving putting your pawns on c4, d4 and e4 with a knight on c3 can't be bad but obviously there is a lot to learn.

If you want to frighten your opponent and take him out of his comfort zone then something like the Barry / 150 attack should do the job. That is where you play d4, Bf4, Nf3 following up with e4 if your opponent doesn't play d5 and then aiming for Qd2, 0-0-0 and an early h4.

I believe that along with the Colle DVD he has also been working on a DVD about the Torre attack. When these are released (probably take a couple of months for Chessbase to do their editing, tidying up and marketing) you might be interested.

Disclaimer: I have nothing to do with either Chessbase or Simon Williams although I have bought their DVDs in the past.


How to decide when is a3/h3 needed? a3/h3 are frequently used to prevent the bishops from pinning the knights.

I always have a hard time deciding whether to play them or not. Playing them loses moves and tempo while not playing can also sometimes become annoying (for example, if the knight is pinned after the bishop has already moved OR worse, if the bishop cannot come back to remove the pin).

Can the experts here help the rest of us with some thumb rules and/or examples?

Let's stick to one color, white here, and everything we'll say will generally hold true for black as well.

Rule of thumb: On the one hand, you generally don't want to move your king-side pawns (such as h3) when you've castled short, unless you have to, and we will expand on what "have to" entails here. The immediate exception to that is when you decide to fianchetto your king-side bishop, e.g., in the Catalan where then you play g3. On the other hand, your queen-side pawns (assuming you've castled short) are to be used more actively to either gain space or prevent an spatial expansion by your opponent.  (the rule is naturally to be taken with caution, chess rarely lends itself to these kinds of generalizations)

The more common cases are when a bishop is pinning your knight on g4 and h3 is an immediate way to try and challenge the bishop, asking it where it wants to go. But there are cases where g4 is not being exploited for a pin but rather as an intermediate square to re-route a knight (to e5 for instance). In either case, if the pin is problematic to deal with, which may be so if you've already made a commitment with your light square bishop and it cannot return to e2, or if the knight re-routing would be an improvement for your  opponent, then you really want to play h3 in a prophylactic way to prevent all of that. Here's an example in the Benko gambit:

 [Title "Benko gambit declined - preventive example"]
 [fen ""]

 1.d4 Nf6 2.c4 c5 3.d5 b5 4.Nf3 g6 5.Qc2 Bg7 6.e4 d6 7.h3 {Stopping any future knight re-routes to e5 via g4, and specially securing e3 for the c1 bishop. Bg4 is altogether less of a concern here in comparison}

And below you find two prophylactic examples of a3 and h3 where they are purely strategic and intentional:

 [title "a) Nimzo-Indian b)London system - (deliberate examples)"]
 [fen ""]

 1.d4 Nf6 (1...d5 2.Nf3 Nf6 3.Bf4 e6 4.e3 Be7 5.Nbd2 O-O 6.h3 {this is largely to secure the h2 square so that we can preserve our dark square bishop for instance against Nh5.}) 2.c4 e6 3.Nc3 Bb4 4.Qc2 O-O 5.a3 {white by choice, not forced, plays a3 to resolve the pressure on c3 in order to finish development more deliberately, with choices such as Bg5 becoming easier to make} Bxc3+ 6.Qxc3 b6 7.Bg5

Then there are reactive cases where tactically one may not have a choice but to challenge a piece on g4 or b4 respectively, in which case although there's no doubt your opponent would be forcing your hand into playing h3 (a3), but you will have to include that move and accept a small set-back. Extreme cases are when a mate is threatened, e.g., a queen on h5 and knight on g4.

Why moving the castled-side pawns would generally be a set-back?

Main reason for that is two-fold: First, as obvious as it may sound, you'd be permanently committing to a pawn structure, second and tightly related to the first, you'd be creating targets for your opponent. The latter may be, to name a few, in the form of weakened dark squares, for instance if there's a dark-square battery on the c7-h2 diagonal that you'd want to preferably deal with by playing g3, but having previously played h3 may make that difficult and g3 would expose h3 and g3 itself to potential sacrifices. Another type of target would be, a pawn push on the king-side by your opponent, challenging h3 with g4 attempting to undermine your king-side pawns and open a file towards your king.

The takeaway here can be generalized: pawn moves in chess are always a commitment, the later you have to commit to them, the more pawn structures you can opt for, and conversely, the sooner you commit to one, be it willingly or forced by your opponent, the earlier you create targets for your opponent. Targets are not always weak pieces/pawns (such as back pawns, or isolated ones), but they can also be strategic targets that can be exploited in your position, prime example being weakened-black/white-squares, or more abstractly, your pawn-breaks in the position can become limited, and the few remaining ones can more easily be prevented/delayed by your opponent, which ultimately means you will have a hard time undermining your opponent's structure and creating active play. This is closely related to space control in chess, which you can read more about here. With all of this in mind, now you can see for example why the English opening is generally is hard to face: it is extremely versatile in pawn structures it can lead to, consequently, the opponent has a harder time to resolve the dilemma of which plan to opt for! Instead, e4 and d4 openings are more committal by definition (as we start by moving a central pawn already), so we can more reliably establish systems against them

Now let's take an extreme example where our rule of thumb is being perfectly illustrated:

 [title "Michael Adams vs Garry Kasparov, Linares 2005"]
 [fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Be3 e6 7.Be2 Qc7 8.Qd2 b5 9.a3 Bb7 10.f3 Nc6 11.O-O-O b4 12.axb4 Nxb4 13.g4 Be7 14.g5 Nd7 15.h4 Nc5 16.Kb1 Rb8 17.h5 O-O 18.g6 Bf6 19.Rdg1 Ba8 20.Bg5 Be5 21.gxh7+ Kxh7 22.Nb3 Nxc2 23.Nxc5 Na3+ 24.Ka2 Qxc5 25.Na4 Nc2 26.Kb1 Qa3 0-1

Notice how Kasparov pushes with a6-b5-b4 on the queen-side in order to launch his attack on white's long castled king and yet never moves any of his king-side pawns until the end as to avoid giving white any entry-points or targets. Notice how Adams had to play earlier a3 in order to prevent b4 as it would force his c3 knight to be mis-placed in turn weakening the e4 support. And having committed to a3 is precisely the target Kasparov used with b5-b4 to open the b-file, which he then exploited beautifully. This is a cherry picked example, but it's very appropriate here because all of our previous points culminate in one game! More generally, Sicilian players are accustomed to this type of pawn structures (i.e., knowing not to commit their king-side pawns and just push as fast as possible on the queen-side).


Who is best at promoting chess? Should FIDE be the one to promote chess.  Or USCF and other national NCFs?

Should it be tournament promoters who profit from more players attending?

Is it the job of local clubs to promote chess?

All of the above??

I have seen local clubs fail because they promote chess instead of promoting the club for the benefit of the players in their town.  I see small towns have successful clubs with no dues and many rated events with dozens of players ,  when some larger cities charge too much, throw the dues money around like they printed it, and rarely have a rated tournament which is usually very poorly attended.

Clearly tournament promoters need to promote chess so they can generate profits.

FIDE needs to promote chess with less urgency as they are the one in charge of chess and the size is less important to them, but still significant.

National federations would tend to be in the middle although IMHO leaning more to needing the members to pay dues so they can survive and thrive.

Now I see that some schools promote chess.  WHY?

Simple answer: it is everybody's job to promote chess.

FIDE stands for "Fédération Internationale des Échecs" which stands for "International Chess Federation". It is their job to promote international chess -

World Championships
Candidates tournaments
Continental Championships
Olympiads

It is the job of the national federations to promote chess at the national and regional level -

National Championships
National Leagues
Regional Championships
Regional Leagues

It is the job of clubs and their affiliates (in some countries the national federation is also run completely by the clubs) to promote chess at the local level

Local Leagues
Local congresses

It is the job of internet companies to promote chess online (although FIDE and the federations sometimes like to try as well)

It is the job of rich sponsors to fill in the gaps and provide the icing on the cake. Here I'm thinking of lucrative, major opens like the Isle of Man, Gibraltar and the big events run out of St Louis Chess club (and bankrolled by Rex Sinquefield)

No one group of organizers is best overall. It would be ridiculous for FIDE to try and run every minor city league. It would be equally ridiculous for clubs to run the World Championships.

Note that I haven't mentioned entrepreneurs for the simple reason that making money from organizing chess tournaments, while possible, is extremely difficult. Whoever can crack the TV market and turn chess into a sport with the same televisual appeal as soccer deserves to be a billionaire.


Was I right to capture the pawn in this position? I played a blitz game against a 1900 player which I won. I'm interested in this position, with me as Black to move.
The computer recommended to take the bishop, but I didn't want to take it immediately, because I don't want to give their rook an open file. I thought if they want to take my rook, they better do it with the g pawn.
[FEN "r2q2k1/2p2ppp/2p2n2/p7/P2pr3/1BB2P2/1PP3PP/3Q1RK1 b - - 0 1"]

I played Rh4 to keep an eye on the pawn and if they were willing to kick it by playing g3, they'll end up with a weakened position. They replied with g3 as expected. And here I could take the bishop or the h pawn then the bishop, which is what I did.
Had I followed what the computer said, I would have been up 2.5 or 3 points in computer evaluation. What I did got me half a point to 0.8, which is strange, hence I'm asking this question. The computer didn't even bother moving the rook to the h-file.
In the position, what would be the best approach?

N.B. This answer is without the aid of a computer. Here I compare 1...Rh4 to 1...dxc3

1...Rh4

The material difference in the given position is exchange + pawn vs. minor piece. This is a difference of 3 pawns. After 1...Rh4, white can win a pawn with 2. Bxa5. On paper this is now a difference of 2 pawns, but computers tend to overvalue pawn structures, so is probably penalizing black for the doubled, isolated c-pawns.

1...dxc3

I think that Black is better after this sequence, because:

Black will soon be up 2 pawns
Black has better placed pieces
Black has the long term strategy of making the light square bishop a spectator by placing most of the pawns on dark squares

[FEN "r2q2k1/2p2ppp/2p2n2/p7/P2pr3/1BB2P2/1PPQ2PP/5RK1 b - - 0 1"]

1... dxc3 2. Qxd8+ Rxd8 3. fxe4 cxb2 4. e5 Nd5 5. Rb1 Nc3 6. Rxb2 Re8


How old was Judit Polgar when she learned to play chess? I found a few publicly accessible biographies of Judit Polgar, including details of her early life. According to the biography on Judit’s website, she was 9 when she first won an international chess tournament. According to this SuccessStory article, she began participating in tournaments at the age of 6. According to this article from “All That’s Interesting”, she was able to beat her father by the age of 5.
But how old was she when she learned how to play?

In her TED talk Giving checkmate is always fun, Judit Polgar says (t=0:59):

My mother taught me the first moves when I was about five years old...


Weak and strong squares I somewhat understand the concept of attacking the king and pieces, but "attacking" squares is a bit of a vague concept for me.

What are weak and strong squares? When do you use them? How do you create them?

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

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

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

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


From the start of the game what is the longest possible series of consecutive white moves where white can do those moves no matter what black does? From the start of the game what is the longest possible series of consecutive white moves where white can do those moves no matter what black does?

So I want the longest list of moves white can do after starting the game no matter what moves black does. So what is the maximum number of moves he can plan ahead and be sure he will be able to do it?

Three moves.

On move 3, Black can crash through with his queen on f2 or d2 via several different squares, forcing White to respond. There is no series of White moves that can prevent all such checks.

[FEN ""]

1. Nf3 (1. e3 e5 2. c3 Qf6 3. g3 Qxf2+) 1... c6 (1... e5 2. c3 Qh4 3. e3 Qxf2+) 2. g3 Qa5 (2... Qb6 3. c3 Qxf2+) 3. e3 Qxd2+ *


Which pieces do I have to keep on the board, to win my endgame? How do I win this endgame?

2R5/pr6/3kp2p/4n1p1/5B2/P4P2/2P1K1PP/8 w - - 0 1

More specifically, I want to know whether I should trade off pieces, and in case of a trade, which pieces I should keep on the board.

I considered three options here:

A Keep all the pieces on the board.
This could be done by 1.Bg3 Kd5 2.Rh8 etc.

B Trade off the rooks.
This could be achieved by 1. Rd8+ Rd7 2. Rxd7 Nxd7 etc.
1...Nd7 is bad because of 2.Kd3 Kc6 3. Rh8!?

C Trade off the light pieces.
This can be done by 1.Bxe5 Kxe5 2.Rh8 etc.

My further questions are:

Is the rook ending in C a draw? If it is possible to win it, how would it be done?
Which endgame is better/easier to play A or B?
I guess that A and B are both winning for White. How are the winning strategies in both cases, i.e. how to win them?
In general, in Rook + Bish vs Rook + Knight endings, who wants to trade of the rooks?

Endgame D, after exchanging rooks AND minor pieces, is a trivial win.

Endgame C, with rooks, looks winning as well but might require more tactful play.

Endgame B, without rooks, is quite an easy win.

Endgame A, with R+B, is winning. The best strategy will probably involve a rook exchange...

Question 4: generally, the side with the bishop wants to keep rooks and the side with the knight wants to keep queens. There are a lot of exceptions though, including cases like this one with material imbalance (an extra pawn).

From the diagram, the logical continuation should be 1.Bg3 Kd5 2.Rd8 Nd7!, keeping rooks. White should win nonetheless. The plan (loosely explained) will be: centralisation, threats against h6/g5, helping the c-pawn forward. A bit of concrete thinking is needed too, because you don't want to allow too much counterplay against your somewhat loose queenside pawns.


What does this chess proverb mean? "Chess is a sea where a gnat may drink from and an elephant may bathe in." ~ Anonymous

The above proverb is scattered everywhere throughout chess literature, folklore and even software.

I have never fully understood its meaning, however.  Does the gnat represent a patzer and the elephant represent a master? Is the proverb trying to say that the game is a game for everyone?

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

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

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


What is the advantage in knowing the fastest winning sequence if I can win with few more moves than fastest sequence? I am studying from Lazlo Polgar's "Chess: 5334 Problems, Combinations, and Games", there are positions with heavy material imbalance for example like a lone King against Queen, 2 Knights and King under the category to find mate in 2 or 3 moves.

Some of them are not easy for me even after few minutes to find mate with the given 2 or 3 moves but I can easily do in 4 or 5 moves.

In cases like this with large material imbalance why should I spend my energy and time in finding the fastest sequence if I can do the same with slightly more number of moves?
What do I gain by knowing the fastest sequence?

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


Is there a USCF API? A while ago there was a site made by NM Jonathan Hilton's father that did some analytics on player's USCF rating histories.

I thought it was a pretty good site, but it disappeared.  There are still some tools like that floating around.  I was wondering if there was some sort of USCF API, or how that sort of data might be grabbed.

I'm not aware of an API, but they way they have it set up it's pretty easy to gather data via a technique called screen/web scraping.

For example, a search on your name gives a link to a specific page with your member id in the URL. Then if you have a programming language/library that is DOM-aware, you can simply figure out where certain things will be, based on the design of the page. Using jquery selectors, and a couple of traversals, that page can be parsed to get the rating as such:

> $("td td td:contains(Regular Rating)").next().find("nobr").text();
"2072
2012-03(Current floor is 1800)"

Nice rating, by the way.

It's a bit painful, and even more painful if they ever decide to change the design of the pages, but eventually you'll be able to parse out all the data you want, and then build a way of collecting data for each member and storing it in your own database for analytics. It wouldn't be that hard to do, just iterate through member ids, and you can get their names, states, ratings, etc.--as much is available on their screens.

Hope that helps.


Anderssen's 'immortal game' I came across Anderssen's 'immortal game':

[FEN ""]
1. e4 e5 2. f4 exf4 3. Bc4 Qh4+ 4. Kf1 b5
5. Bxb5 Nf6 6. Nf3 Qh6 7. d3 Nh5 8. Nh4 Qg5
9. Nf5 c6 10. g4 Nf6 11. Rg1 cxb5 12. h4 Qg6
13. h5 Qg5 14. Qf3 Ng8 15. Bxf4 Qf6 16. Nc3 Bc5
17. Nd5 Qxb2 18. Bd6?

I was curious to know whether Bd6 is really a good move or not. StockFish 10+ does not think it is all that great. At the default depth 18 it evaluates it wrongly (strangely it gave different values whenever I forced reevaluation, but typically between -4 and -5), but even at depth 29 it still evaluates it as 0, with main line 18... Qxa1+ 19. Ke2 Qb2 20. Bxc5 Qxc2+ 21. Kf1 Qxc5 22. Qf4 Kd8 23. Nd6 f6 24. g5.

But it seems even 18... Qxa1+ 19. Ke2 Bxg1 20. e5 is not too bad for Black, and I think continues:

[FEN ""]
1. e4 e5 2. f4 exf4 3. Bc4 Qh4+ 4. Kf1 b5
5. Bxb5 Nf6 6. Nf3 Qh6 7. d3 Nh5 8. Nh4 Qg5
9. Nf5 c6 10. g4 Nf6 11. Rg1 cxb5 12. h4 Qg6
13. h5 Qg5 14. Qf3 Ng8 15. Bxf4 Qf6 16. Nc3 Bc5
17. Nd5 Qxb2 18. Bd6? Qxa1+ 19. Ke2 Bxg1 20. e5 Ba6
21. Nc7+ Kd8 22. Nxa6 Qc3 23. Bc7+ Qxc7 24. Nxc7 Nc6
25. Nxa8

It seems Black is not really dead yet. Am I missing some subtleties?

I also noticed that the wikipedia article has an apparently inconsistent footnote [6], which implies that 18...Qxa1+ is better because it likely leads to 19. Ke2 Bxg1 20. e5., but this is precisely the same position that Anderssen reached in the actual game, which the article says led to Black's defeat...

You are correct that 18.Bd6? is, indeed, not the best move (the simple Re1! threatens Nc7-a8 winning on material). Bd6 has widely been considered a mistake for many years now. Black holds with 18...Qxa1+ 19.Ke2 Qb2! 20.Bc5 Qc2 21.Kf1 Qc5 22.Qf4 and black has several moves that are equal, but in the last few moves, it is white that has to find the only moves along the way.

[fen "rnb1k1nr/p2p1ppp/3B4/1pbN1N1P/4P1P1/3P1Q2/PqP5/R4KR1 b - - 0 1"]

1...Qxa1+ 2.Ke2 Qb2! 3.Bc5 Qc2 4.Kf1 Qc5 5.Qf4

Of course, this was played at a time where "romantic chess" was still at its peak, and winning practically was not their mindset. It was sacrifice, and if your opponent offered pieces, you took them.

Lastly, with computers getting stronger every year, who knows, maybe 18...Qa1 will eventually still be found to be winning for white, but that is a moot point since Re1 kept the material and the attack.


How does Alphazero Respond to the QGD? I recently started reading Game Changer, the new(ish) book on Alphazero, and I'm really enjoying it. My one issue so far is that I can't find, in the book or elsewhere, games where Alphazero played the white side of
1. d4 Nf6 2. c4 e6 3. Nf3 d5,
forcing a QGD with the knight placed on f3 very early. If anyone knows of any games that went this way, please let me know!

There were a select of games published played between AlphaZero and Stockfish 8, see e.g. here on chess24. Some of them were played without book and some with the TCEC opening book, which I reckon led to a bigger likelihood for the QGD to occur.

Considering that QGD itself is an opening for black, how frequently they occurred in AlphaZero's games playing the white side is mostly dependent on how compliant Stockfish was to playing such systems. As it happened and whether it was directly or by transposition, QGD structures did occur a few times, at least among the ones I can recall/find at the moment, which I will share below along with some other closely related lines that can potentially be of interest to you. Otherwise, and in particular when without a book, Stockfish seemed to favour lines more along Nimzo-Indian and Queen's Indian defense.

Since the games tended to be quite long, I will only include a portion of the starting moves of the games and provide a direct link to each game so you can study the games in their entirety on your own.

With TCEC openings:

Game 82 QGD Vienna variation, from move 7 off-book:

 [title "TCEC openings, game 82, AlphaZero vs Stockfish 8 (draw)"]
 [fen ""]

 1.d4 e6 2.c4 d5 3.Nc3 Nf6 4.Nf3 dxc4 5.e4 Bb4 6.Bg5 b5 7.a4 c5 8.axb5 cxd4 9.Bxf6 Qxf6 10.Qxd4 Qxd4 11.Nxd4 Bc5 12.Nf3

Game 85 QGD Harrwitz Attack, from move 11 off-book:

 [title "TCEC openings, game 85, AlphaZero vs Stockfish 8 (draw)"]
 [fen ""]

 1.d4 e6 2.c4 d5 3.Nc3 Nf6 4.Nf3 Be7 5.Bf4 O-O 6.e3 c5 7.dxc5 Bxc5 8.a3 Nc6 9.Qc2 Qa5 10.O-O-O Be7 11.h4 a6 12.Kb1 Rd8 13.g4 dxc4 14.Rxd8+ Bxd8 15.Bxc4 Nxg4 16.Rg1 Nf6 17.Ng5 g6 18.Bd3 e5 19.h5 exf4 20.Qb3 Qc7 21.hxg6 hxg6 22.Bxg6 Kf8 23.Bxf7 Bf5 24.Ka2

Game 1, Semi-Slav (nearly QGD) mainline, Semi-Slav lines are always closely related to both Slav and QGD due to the rich transpositional lines that exist between them. From move ...12 off-book:

 [title "TCEC openings, game 1, AlphaZero vs Stockfish 8 (1-0)"]
 [fen ""]

 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 e6 5.e3 Nbd7 6.Qc2 Bd6 7.g4 Bb4 8.Bd2 Qe7 9.Rg1 Bxc3 10.Bxc3 Ne4 11.O-O-O O-O 12.Be1 b6 13.h4 Bb7 14.Ng5 Nxg5 15.hxg5 Qxg5 16.f4 Qe7 17.Kb1 c5 18.Bd3 g6 19.cxd5 cxd4 20.e4 Rac8 21.Qh2 f6 22.f5 exd5 23.fxg6 hxg6 24.Rh1 Qg7 25.Bc2 Ne5 26.Bb3

Without book:

Game 15, Semi-Slav (nearly QGD):

 [title "Without opening books: game 15, AlphaZero vs Stockfish 8 (1-0)"]
 [fen ""]

 1.Nf3 Nf6 2.d4 d5 3.c4 e6 4.Nc3 c6 5.Bg5 h6 6.Bh4 dxc4 7.e4 g5 8.Bg3 b5 9.h4 g4 10.Ne5 Nbd7 11.Be2 Nxe5 12.Bxe5 Rg8 13.O-O Bb7 14.Re1 a6 15.g3 h5 16.Qc2

The list is by no means exhaustive, you might find more examples by browsing through all the available games.


Which chess variant has the largest board? The largest I could find was for Double Chess, with a 16x12 board. Is there a variant with a bigger board? It doesn't have to be a variant in which chess pieces follow their orthodox movement rules.

Taikyoku shogi should be a good candidate. It was created in the 16th century, so it's a variant that has actually been played. The board size is 36x36, and it has 209 different types of pieces.


What are good openings for White during a blitz game? It seems as though White can easily dominate the tempo in a blitz game through a strong, aggressive opening. Is this the case? What openings are strong for White when there is a short time limit (e.g., in blitz)?

I think this depends very much on how strong you are.

That said, I had some success with the Ponziani. It is not the "best" opening, but solid, and many players don't know it and lose some time thinking about the next moves. The theory is easy, and there are several traps black can fall into (my favorite is when black takes the "unprotected" e4 pawn with the knight and you can fork it with Qa4+).

Generally it might be a good idea to play aggressive (e.g. Steinitz' Qh4 in the Scotch game) and to try to throw the opponent out of the book as soon as possible. Of course the opening must be still playable, and you need to know some theory.


What is accepted and declined in chess moves? I'm very beginner in chess. I was just going through some of the opening moves like King's gambit,Budapest gambit,Queen's gambit. I encountered things like Queen's gambit Accepted or Declined kind of moves. Can somebody please explain me briefly about the logic? I know this very basic question but i googled and couldn't find appropriate answer. It might be useful for all beginners

A gambit is an opening where one player sacrifices a pawn (or more) to gain some other advantage. The opponent 'accepts' by taking the pawn, or 'declines' by not taking the pawn.

For example, in the Queen's gambit after 1.d4 d5 2.c4, black has at least these two options, 2...dxc4 or 2...e6. These variations are then called "Queen's Gambit Accepted" and "Queen's Gambit Declined" based on Black's choice.

Note that another common move, 2...c6, also declines the offer, but because the name "Queen's Gambit Declined" just happens to be the name of the variation 2...e6, this has a different name ("Slav Defense").

[fen ""]
1.d4 d5 2.c4 {White offers the undefended pawn on c4.} e6 {Black declines the offer.} (2...dxc4 {Black accepts the offer.})


Is Stockfish 11 (level 20) beatable? I have heard many people saying, “Hah! I beat Stockfish,” and one saying, “I am the best chess player ever! I beat Stockfish.” So I wonder if it is possible, just to know whether I should try to beat it. I tried to play it once; I barely played 25 moves.

The answer is that they either played it on some very handicapped mode, they took back A LOT of moves, or they are probably lying.

Stockfish 11 is currently rated about 3607, and that is in standard chess. Computer programs are typically even HARDER to beat for humans at even faster controls.

There is a reason elite humans have not played matches against computers for a long time: even the Carlsens of the world cannot beat them any more. According to the ELO winning expectancy calculator, there is currently a 745 point difference between Stockfish 11 and Carlsen, and per the chart, that gives the computer a 99.5439696% chance of winning.

Note: The ratings used above are from different rating pools, and thus, are not truly directly comparable, but used as a rough estimate of what would happen between the computer and Carlsen.


Endgame improvement books I am not playing a bad game, but my endgame is not so good. How can I improve my endgame? Please suggest me some good books for that.

Yasser Seirawan's Winning Chess Endings - Very good book, especially for beginners. Written by one of the best instructional authors out there. This book is written for beginner-intermediate level so it is very easy to understand, but has many lessons that can carry through to advanced levels.

Dvoretsky's Endgame Manual - Very indepth guide. Has just about anything that most players would need until professional level, and even there it has strong value. Can be fairly complicated at times, and assumes at least intermediate level skill from the reader. It can be a good reference manual however, as each topic is clearly outlined. Just be warned that there are many complicated situations that almost never arise in anyone's game, so you should focus your study on more important endgame techniques before conquering specific situations.

Silman's Complete Endgame Course - More like a guide than Dvoretsky's Endgame manual, allowing beginners to pick up the book, and progress through until master level endgame technique (as suggested by the front cover). This is the one I most recommend as it is much simpler for most players with less clutter.

Of course, there are loads more out there! Chess.com has asked this question before, and produced fairly consistent answers from players on the website. In the end, it will largely come down to your skill level, dedication to study and personal preference.


What was the point of Shirov's 47...Bh3? One of the most famous moves ever is Shirov's 47...Bh3!! in Topalov - Shirov, 1998.

[FEN "8/8/4kpp1/3p1b2/p6P/2B5/6P1/6K1 b - - 0 47"]
[Event "Linares"]
[Date "1998"]
[White "Veselin Topalov"]
[Black "Alexey Shirov"]

I've always taken that for granted and never really thought about it. Can anybody give an explanation of why it is the best move?

I interpret the question as follows

  How can a player arrive at ...Bh3?

This is tightly connected to the point behind ...Bh3. With a material advantage, black is clearly looking for a win. Yet, it is well known that opposite colored bishops give the defending side a strong chance to draw. Thus, precise play is required.

Black's plan is

Get the king to e4 by Ke6-f5-e4
Do d5-d4 to limit the enemy bishop
Push a4-a3-a2
Queen one of the pawns

White's plan is

Get the king to d4 by Kg1-f2-e3-d4
Prevent the enemy king from reaching e4
Prevent the enemy from pushing d5-d4
Prevent the enemy king from supporting the black a-pawn

Next, black has to answer the question

  What is the most direct way to make the plan work?

The key point is that black's bishop doesn't really help much in promoting the pawns. It is the king that plays the key role. Thus, sacrificing the bishop to win a tempo makes total sense! In addition, after gxh3, white can no longer create a passed pawn on the kingside! Thus, the bishop sacrifice wins a tempo and ruins white's counter-play. For example

[FEN "8/8/4kpp1/3p1b2/p6P/2B5/6P1/6K1 b - - 0 47"]

1...Bh3! 2.gxh3 Kf5 3.Kf2 Ke4 4.Bxf6 d4 5.Be7 Kd3 6.Bc5 Kc4! 7.Bd6 Kc3 8.Ke2 Kc2 9.Bb4 d3+ 10.Ke3 a3 0-1


What are the dates each of the endgame tablebases were completed? I'm curious to get a rough sense for when chess could be solved if Moore's law, and algorithm improvements continue, and I thought a good way to get a rough idea would be to extrapolate based on when the endgame tablebases for 2 to 7 pieces was completed.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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


Best book with several annotated games by top GMs with the Dutch I'm looking for annotated games by top GMs featuring the Dutch defense.  These could be in a book with lots of other non-Dutch games.  Unfortunately Botvinnik's "Botvinnik: One Hundred Selected Games" as I recall doesn't have quite a half dozen and they are all Stonewalls: I'd like some "Classical" variation games too.  How about "Zurich International Chess Tournament, 1953"; Bronstein played the Dutch, didn't he?  Unfortunately with Amazon's "search inside" feature it doesn't look like the games were indexed by opening.  As you can tell I don't mind if the games are old-ish (and this will weed out lots of Leningrad Dutch's I'm not necessarily interested in at this point), though I'm also open to more recent games too.  Thanks in advance.

The World Championship Match between Botvinnik and Bronstein in 1951 contains quite a number of Dutch Defense games. I didn't find many books about the match, but there was one by Botvinnik that may provide a good reference point.


Center Game: Von der Lasa Gambit I am looking at this game and saw this opening.
[FEN ""]
1.e4 e5 2.d4 exd4 3.Bc4 Bc5 4.Bxf7+ Kxf7 5.Qh5+ g6 6.Qd5+ Kg7 7.Qxc5

The 3.Bc4 is new to me. I think people usually play 3.Qxd4. So, my questions are:

What is the idea behind 3.Bc4? Simply put pressure the f7 square?
It seems that 3. ...Bc5 allows White to sacrifice the bishop because he could take a bishop back at 7.Qxc5. Are there any other reasonable moves for black after 3.Bc4?

I am a beginner in chess, so a more detailed explanation would be much appreciated. Thank you in advance.

3. Bc4 is one of those fairly regular moves that defer the opening selection of the Scotch Gambit (1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Bc4) and the Danish Gambit (1. e4 e5 2. d4 exd4 3. c3 dxc3 4. Bc4). 3... Bc5? is a well-known mistake because of the Bxf7+ followed by Qh5+ sequence.
That's why Black's move is normally 3... Nc6 or 3... Nf6.


Is prophylaxis a feature of the hypermodern school? Wikipedia mentions prophylaxis in the article of hypermodernism in chess. But is it really a feature of the hypermodern school? I have not seen prophylaxis in any other book or article about hypermodernism in chess. One exeption is the chapter about prophylaxis in the book My Shstem, which is also describing hypermodern chess.

It's because Nimzowitch  was the foremost figure amongst the hypermoderns, you can't mention hypermodern school without Nimzowitch. And the prophylaxis idea first introduced by him, in his famous book Mein System. If we would call him the father of modern chess, it wouldn't be wrong.

His ideas was challenging the dogmatic rules set by Tarrasch, which widely considered as the best strategy at the time.

There is an excellent book named Secrets of Modern Chess Strategy: Advances since Nimzowitch, which covers prophylaxis and lot more. I recommend you to read it.


Analysis of a position in order to find the best move I am trying to learn to play chess, but it is not an easy task. I am playing as much as possible and try to watch games an reading in order to learn. I am playng on Chess.com, and a lot of times I find myself in this position:

[fen "r1bqkb1r/pp2pppp/2np1n2/2p5/2B1P3/2NP1N2/PPP2PPP/R1BQK2R b - - 0 1"]

I am black, and it is my turn to move. The sequence of moves is the following:

on the left there are the moves white did, and on the right there are my moves, so black's moves.

From this position my move was e5, but I am not sure it is a good move.

What is the best move in this position? And can I correct something in my sequence of moves so far? Thanks.

I am a beginner, so I have a lot to learn.

First, your move e5?? was a blunder. 6.Ng5 won a valuable pawn after the forced 6...Be6 7.Nxe6 fxe6 8.Bxe6.

White's opening is not very ambitious when he does not play d4, so you would probably have an easier time getting in the "standard" Sicilian freeing move d5. When black gets that move in, he is usually equal, if not better. So instead of 5...e5??, 5...e6 was better helping to achieve that goal of d5.

In the final position, after 6.Bg5, Be7 looks best, but you already weakened d5 a lot, so in most cases, black will trade on f6, and sink a very powerful knight onto the d5 square.

As you are finding, learning how to play the game does not take long, but learning to play well can take a lifetime (depending on your goals).

 [FEN ""]

 1. e4 c5 2. Nf3 Nc6 3. Nc3 d6 4. Bc4 Nf6 5. d3 e5 (5... e6 6. O-O Be7 7. Bf4 (7. Be3 $4 d5 $1 8. exd5 exd5 9. Bb5 d4 {A typical trap}) 7... d5 8. Bb5 O-O {and it is, as we say, "a position"...black has equalized}) 6. Bg5 Be7 7. Bxf6 Bxf6 8. Nd5


Ratings criteria chess24 My rating in chess24 is 1560, is the rating based on my wins or any other criteria considered? I can see the scores change when I win or lose.

According to this page on their site, "A new member starts with a rating of 1800 and after a rated game that number changes. The change depends on the result of the game and your opponent's strength."

I have no reason to assume this is incorrect or incomplete.  These are probably the only factors.


Where can I play Quantum Chess online for free? I saw some videos featuring a chess variant called Quantum Chess on YouTube. It looked very interesting to me, so I decided to try to find it online for free, but I couldn’t. Does anyone know of such a place?

Try truly quantum chess. It is an implementation of quantum chess by yours truly, the rules are sligtly different from the rules of the steam version though, for example, pawns can quantum move.


How can I continue in this situation? I am stuck for a move as White. Is there any way to go for a check-mate? I would take the black rook with my rook at d1 but would that be a bad decision?

You don't have a checkmate plan. Let's talk about it when you are able to queen a pawn. 1.Rxd8 is a reasonable move here.


Stockfish's algorithm I'm trying to understand how Stockfish thinks, how it calculates the best move.
I'm reading open source code, but it's not clear. I want to know, should I know some theory about algorithms to understand that code? Or is it possible without knowing anything? If there are important algorithms, please tell me what I should learn before reading source code.

If you are reading the code to become a better player, you won't have much luck. The tricks used are only useful when you have the memory and computational power of a machine.

If instead you are reading it to learn about chess programming, the following wiki is a great resource https://chessprogramming.wikispaces.com


Relation between Elo and search depth for basic minimax If we use the most basic approach to a chess engine (for example, for a codegolf): minimax to a fixed depth with the material count as static evaluation, then how strong is this algorithm?
This of course depends on the search depth, but since such engines have been implemented tens of thousands of times, I hope there are some resources that can say something about the strength as a function of the search depth. I haven't been able to find any so far.
It also depends on the material values, which are not always the same.

If we use the most basic approach to a chess engine (for example, for
a codegolf): minimax to a fixed depth with the material count as
static evaluation, then how strong is this algorithm?

Not very strong.
Even though the material value is a significant factor in evaluation. There are many more factors that you need to consider to build a strong evaluation function.

Mobility
Center Control
Pawn structure
King Safety
Blocked pieces
Tempo

These are just the key points, there are in-fact many more factors you can add.
Now, coming back to the question which is the relation of depth to the strength of the engine

Short answer:
The greater the depth, the stronger the chess engine is. With experience, I can say that the engine you described in your question would be quite weak, and could be defeated by any amateur chess player.

Long Answer:

I would say that it has a significant impact.
The problem is that depth doesn't necessarily denote the number of moves you have searched. This is because modern chess engines apply something called pruning which is reducing the number of moves it evaluates. It cuts down on a huge number of moves that seem bad during the beginning of the search, which can cut down a huge branch of moves. Due to this engines like Stockfish can reach depths of more than 15!
If you use a basic algorithm like minimax that applies no pruning, depth 6 with a reasonably fast generator function will already be slow. Anything after depth 7 would just take forever.
If there are an average of 20 moves in a position, this is how many moves you would be evaluating approximately when the depth increase
depth 1 = 20
depth 2 = 400
depth 3 = 8,000
depth 4 = 160,000
depth 5 = 3,200,000
depth 6 = 64,000,000
depth 7 = 1,280,000,000

1.2 trillion moves. That is a LOT of moves. And chess engines today search moves NOWHERE NEAR that number.
I gave ethereal about 7 seconds to search for moves in this position for black

Using arena I could see the details of this search, and to my surprise, it had gone to a depth of 22! Does this mean it evaluated 134217730000000000000000000000000000 positions?
No, it evaluated only 9,799,1101 positions. Again, because of pruning.
It did go to a depth of 22 but it did not evaluate all the variations.
Using a simpler search algorithm like minimax which applies no pruning, you will be seeing the same number of moves at depth 4-6 but those moves have very little meaning. Because a huge part of them could start with you hanging one of your pieces.
So your evaluation function is weak as it only considers material balance, and your search algorithm isn't great either, you can understand why this engine will be weak.
EDIT: As I said earlier the greater the depth of the search, the stronger the move it picks.
At greater depths, the difference will only become greater because a single increment in the depth could result in searching millions of more nodes. There is no simple relation between the elo and the depth of an engine because as I also mentioned earlier depth is one factor amongst a hundred others.
If you see the top engines today, all of them search to a similar depth, but some are very clearly stronger than the other. Which just proves my point.


Why did Spassky play the King's Gambit? If the King's Gambit is unsound, how could a world champion play it often?

King's Gambit is not really a horrible opening. Just after all the theory that has been amassed since Spassky has shown that it loses white's advantage. There are other openings that create a good amount of initiative without the possibility of falling into a losing position.


What is the negative thinking method in chess? A long time ago, someone told me about the negative thinking method. There is a saying that in every position there is a move that will not worsen it. The method goes as follows.
You chose n candidate moves which are possible in the position.
You try to find out some good moves. If you reject n-1 move because they are worsening the position you can immediately play the n-th candidate move.
It has its, flaws but it could be useful sometimes. I tried to find out more about this technique, but I did not have luck. Has anyone here heard about that or something similar?

Taken literally, this seems a bit absurd. You don't explicitly reject moves that are so awful that no chess player would seriously consider them in the first place. Furthermore, there isn't a simple dichotomy of bad moves and good moves, where all but one move is bad (so that the good one can be arrived at by a process of elimination). There is more typically a continuum between awful moves and excellent moves, with many of the non-excellent moves not being actually bad but just not as good as possible.
On the other hand (if taken less literally) this way of thinking is related to prophylaxis in chess, which is a recognized approach to chess planning. Petrosian was a virtuoso in prophylaxis. He likely sometimes made moves after determining that any plausible alternative left his position potentially vulnerable to some future threat.


Is the chess game from the movie "Revolver" a plausible game? The movie "Revolver" has a scene with a chess game: https://www.youtube.com/watch?v=eI1oSkX-Zag

Is the game plausible?

The scenes we see in the movie are not completely coherent, some of the things we see are in the wrong order, and the initial chessboard seems to come from the same game, but it is not completely consistent with what happens later. Anyway, the combination they play, with the checkmate, looks like this. Of course the combination is quite simple, and it does not match with the idea they want to give in the movie (the two people are supposed to be tournament players, as we see from the scenes with the chess clocks), so for them this combination would be trivial, and the suspence we see in the last three moves is quite unjustified.

[FEN "r1b1r1k1/pp1nbppp/4p3/q2pP3/8/2RBBN2/PP2QPPP/5RK1 w - - 0 1"]

1. Bxh7+ Kxh7 2. Ng5+ Bxg5 3. Qh5+ Kg8 4. Bxg5 Nxe5 5. Rh3 Ng6 6. Qh7+ Kf8
7. Qh8+ Nxh8 8. Rxh8# 1-0


Game ended with a handshake In a amateur game, black offered a handshake and white shook hands with him and neither spoke any word and the game ended. Later they had a dispute whether the game is a draw or a win for white. Black claimed that his offering of a handshake was a draw offer and when white shook hands, white accepted his draw offer. White claimed that black's offering of a handshake was a resignation.

It is an amateur game and there is no game record. So what should the arbiter do in this situation? Here are a few possibilities:

Claim this game as a draw.
Claim this game as win for white.
Try recovering the position when the game ended and ask them to keep playing from there. (This option may not be feasible as without a game record, they may not agree with the position)
Order a rematch.

Edit: I do not remember for sure but it may be a position that is obviously a draw but it appears one side is losing to an inexperienced player. For example, King at the corner vs rook pawn + bishop of "wrong colour".

From my experience (small to medium central European Opens), offering a handshake without words is a commonly accepted form of resignation.

The handshake is not part of any official rules. However, there is some reasoning behind it:

You shake hands after the game ended (just as you do before it starts). So you only start extending your hand once that end is "set in stone".

If you extend your hand without a concrete reason on the board for an end of the game (checkmate, stalemate, 3-fold repetition etc.), you silently imply the other possible reason: That you just resigned, which is possible unilaterally. The "silently" part is the reason why this is done this way: It's less disturbing for neighbouring boards than saying "I resign" or laying down your king (in many piece sets, you can't make sure that it doesn't start rolling around).

If you instead wanted to only offer a draw, the game would not have ended (yet), as your opponent still has to accept. Thus, extending your hand makes no sense yet. But conversely, if you (properly by words) offer a draw, now your opponent may offer a silent handshake! Because once they (silently) agree to your draw offer, the game is over, and they can indicate this by stretching out their hand.

Of course, this "implied" way of ending games, even if it is more polite to other ongoing games, has the drawback that lead to the question here: It requires that both players are on the same page of what is actually implied. Even more problematic than the question are for example cases where one side saw a 3-fold repetition and implied "draw", but the other didn't see the repetition and assumed "resignation". Probably not the case here, it sounded like neither mentioned anything else but resignation or free draw offer.

Edit: Because the question came up why the players would act this way, there are some thinkable scenarios:

Black was dishonest. He deliberately acted ambiguously to trick White (in the hope that the arbiter would be convinced of his story that he only wanted to offer a draw). (correct result: 1-0)
Black was very inexperienced. Sometimes, weaker and especially younger players have the habit of always offering a draw before they resign (sometimes no matter how lost their position is), in the vague hope that the opponent is nice or doesn't see how winning they are. The handshake genuinely was intended to be a draw offer that White misinterpreted. (correct result: 1-0 with a degree of uncertainty. In my opinion, White should not be punished for acting in good faith, while Black with certainty did not offer a draw the correct way and thus has the weaker case).
It was actually White who was dishonest. We don't know the position. Maybe it wasn't actually all that winning and White exploited Black's naivete of not explicitly offering a draw by words. (correct result: 1/2-1/2)

All these cases are mostly applicable to amateur tournaments. Top (and even advanced) players know that they just look like fools if they offer draws in lost positions or try to cheat that way.

To know which of these cases applies, we need more information (for example, what was each player's rough evaluation of the final position, how reasonable can we expect both players treat handshakes as resignations/draw offers? etc.).


Move evaluation on armageddon games I am wondering if there is a Stockfish-like evaluation of moves that could take in account armageddon rules, the rules being that you lose if you draw.

I would imagine a strategy of just trading everything off symmetrically would be completely reasonable in a regular game but in armadeddon you lose on a draw, so you have to try something differently.

The same ideas apply to some openings which are likely to give drawish results.

If you set the contempt factor really high in an engine it will likely be able to play armageddon. Contempt factor is how much it accepts (or doesn't accept) draws. If contempt is high enough it should view a draw just as bad as losing.
https://www.chessprogramming.org/Contempt_Factor is a good article to read on contempt factor if you're unaware of the concept.


Do most amateur players play aggressively? I am an amateur player and I play blitz games with players with ratings around 1500. My impression is, most of these players play very aggressively. I seldom see players who prefer a quiet, solid game, such as Karpov or Petrosian did. (Of course, I am only comparing playing style, not strength).
Is it correct to conclude that most amateur players like to play aggressively? I am not sure if this is only my impression, or it can be supported by statistics. If so, why?

Do most amateur players play aggressively?

That's a very broad and sweeping generalization because, for a start, the vast majority of chess players are amateurs. Very, very few are professionals. Very, very few can actually make a living from chess by playing, coaching or teaching. Not even all grandmasters can make a living from chess.
Then there is the biblical saying (from Ecclesiastes / Kohelet): "There is a time and place for everything under heaven." as immortalized by Mary Hopkins. On the chessboard too there is a time for aggression, a time for quiet development, a time for prophylaxis, etc., and a good player will be aggressive when the position calls for it.
So, I suspect the answer is "No", although it is probably true that most very weak players are over-aggressive. To understand why, it's worth looking at the major factors which separate very weak players from strong players:

Strong players understand one of the core principles of opening development: "First develop your pieces (trying not to move any piece twice until all the pieces have been developed) and only then think about attacking." (Nimzowitsch: "My System")
Probably the biggest difference between strong and weak players is not calculating ability but the ability to correctly evaluate a position. One of the saddest ways weaker players lose to stronger players is by doing some calculations and evaluating the resulting position as equal while the stronger players evaluate the position as materially equal but positionally crushing. That position is duly reached and the weaker player is crushed without ever knowing why (unless they ask the other player during the postmortem). Hint: when you lose to a stronger player in a serious game always ask for a postmortem if there is time.
Strong players play prophylactically (again Nimzowitsch: "My System"). Once past their opening knowledge they continually ask after every opposition move "Why was that move played? What are the plans? How can I stop them?". The weak player rarely does this unless the opponent makes a very obvious move threatening a capture or mate.


Should I play the Cozio defense deferred? The Cozio defense to the Ruy Lopez:

[FEN ""]
1. e4 e5
2. Nf3 Nc6
3. Bb5 Nge7
4. O-O

The Cozio defense deferred:

[FEN ""]
1. e4 e5
2. Nf3 Nc6
3. Bb5 a6
4. Ba4 Nge7

The deferred variation speaks more to me because I typically play a6. From the Opening Explorer, I think the best continuation for white is d4 followed by bringing the queen out to the center:

[FEN ""]
1. e4 e5
2. Nf3 Nc6
3. Bb5 a6
4. Ba4 Nge7
5. d4 exd4
6. Nxd4 Nxd4
7. Qxd4

I'd like to know more about these defenses. What types of games do they produce? Is anyone known for playing them? Are they prone to traps or other tactical considerations?

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

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

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

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

      [FEN ""]
      [StartPly "5"]

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


Is the FIDE International Organizer title required to organize high level FIDE tournaments? The FIDE Handbook has a section called Regulations on Seminars & Title Award for Organizers where it describes what you need to do to get the FIDE International Organizer title. It says:

  Scope / Mission: To get the FIDE licence for the organisation of FIDE,
  Continental and International tournaments.

Now, I know that the title is not a requirement to organize a low level FIDE rated tournament because I have done so in my club along with another player who also has no organizer title.

My question is: is it a requirement for high level tournaments and if so, where is the border between requiring the title and not needing it?

It looks like the answer is "No" because Arkady Dvorkovich, who has no organizer title, was the chief organizer for the FIDE Grand Prix Series Riga- 2019, FIDE Grand Prix Series Riga- 2019 Blitz Tie-breaks and FIDE Grand Prix Series 2019 Rapid Tie-breaks tournaments.

However there is an additional paid position for "FIDE World Events" called a "FIDE Technical Director". The role is described here.

  FIDE Technical Director (FTD) is the overall observer of a FIDE
  World Event
  The FIDE Technical Director FTD is appointed by FIDE and must be a licensed International Organizer
  Main duties of the FIDE Technical Director"

  To be responsible for the communication with the Organizer after the approval and circulation of the tournament regulations.
  To check before the start of the competition if the organization adheres to FIDE standards.
  To check if the Organizer provides to the participants the conditions offered in the bid and described in the event invitation.
  To be contacted by the National Federations as the FIDE Representative.
  To ensure the contact of the competitions according to FIDE rules and regulations
  By the end of the competition to send his report to FIDE including and comparing the final evaluation with the bid-evaluation.

  Organizer provides the following conditions to the FIDE Technical Director:

  Single room (FB- 3 meals) 2 days before the start of the competition till departure
  Air-travel expenses & transportation to the venue

  FIDE pays to the FIDE Technical Director the stipend in accordance with the Financial Guidelines for the Technical Officials.


How does b3 prevent e5 here? [FEN "rnbq1rk1/ppp1b1pp/3ppn2/5p2/2PP4/5NP1/PP2PPBP/RNBQ1RK1 w - - 0 1"]

White plan is to play b3 and then Ba3 to render the move e5. But how does it prevents e5?

Currently e5 is not playable due to pawn loss. b3 is good as if ever e5 occurs after preparing for it with Nbd7, dxe5 dxe5 would make the long diagonal accessible to the bishop forever. In double fianchetto positions, an open centre is desired for maximum range of bishops.

Obviously, It's not strict, e5 is a very important break in many dutch positions.

This is an opening position. Many things are possible here. You can read some books on classical dutch for more insight into this position.


Were my sacrifices sound in this game? [FEN ""]

1.d4 Nf6 2.c4 e6 3.Nf3 b6 { I wasnt familiar with theory here, but I vaguely remembered seeing a kingside fianchetto somewhere and it seemed reasonable. } 4.g3 Bb7 5.Bg2 c5 6.O-O Be7 7.Nc3 cxd4 8.Nxd4 Bxg2 9.Kxg2 { Maybe not ideal, but I think white is better due to my lead in development, my strong c-pawn and in particular the weakness on d6. } 9...O-O 10.e4 Qc7 11.b3 Nc6 12.Ndb5 { The point is to take control of d6. The attack on the queen allows me to do it with tempo. } 12...Qb7 13.Nd6 Bxd6 14.Qxd6 { I might lose time if black finds a way to attack the queen. As long as I prevent d7-d5 and can coordinate in reasonable time I think I have a clear edge. Tell me if I'm wrong. } 14...h6 { ? I think this move warrants a ? because it does nothing to fight for d6 or counter attack. } 15.Rd1 { I wasnt sure if the bishop was going to f5 or a3 so I moved the rook first. } 15...e5 { Whether this move is good or not depends on whether my sacrifice is sound or not, which is beyond my skill to say anything definite about. } 16.Bxh6 Nd4 { I expected Ne8, but here I am not sure of anything. } 17.Rxd4 { Is this sound? My knight will be beautiful on d5, blacks rooks will both remain very passive. I intuitively felt like this gave a clear advantage. } 17...exd4 18.Qxd4 gxh6 19.Qxf6 Kh7 20.Rd1 Rae8 21.Rd6 Re6 22.Qf5 Kg8 23.Qg4 Kh8 24.Rd5 Rg8 25.Qh4 Kh7 26.Rf5 d6 27.Nd5 Kh8 { I couldnt find a way to proceed with the attack, though maybe I should have kept looking. Instead I decided to simplify a bit and hope that my extra pawns and strong knight will be enough. Intuitively I was sure that it was, but objectively I might have been wrong. } 28.Rf6 Rxf6 29.Qxf6 Kh7 30.Qxd6 Rg6 31.Qc7 Qxc7 32.Nxc7 Rd6 33.Nd5 Kg6 34.f4 Kh5 35.Kf3 f6 36.f5 Rc6 { ? This allows mate. Was white winning here if black had avoided the mate? I see no counterplay and white will soon create several protected passed pawns. } 37.Nf4 Kg5 38.h4

I did analyze the game and it's just time consuming to annotate the whole game about all the inaccuracies and blunders made by black or white as there are many of them. Instead i wanna be more straight forward and answer your actual question about whether your sacrifices were good enough.
So the main sacrifices which i assume you are talking about are 16.Bxh6 and 17.Rxd4.
After 16.Bxh6 with perfect play, white can only achieve a draw, obviously your opponent made a blunder by playing 16...Nd4 (this loses him right away, I'll tell which is the best continuation after this move in my next explanation about 17.Rxd4)
Why 16.Bxh6 is not the best?, because of
16...Ne8 (gets away from the queen attack of Qxf6 if after gxh6, also attacks your queen and threatens gxh6) 17.Qd2 (getting away from the knights attack and defending the h6 square, so now you are sacrificing your bishop for g and h pawn) 17...gxh6 18.Qxh6 (after this you are a piece down for 2 kingside pawns, which usually is good when you can complete the attack on kingside to gain an advantage, but here there is no other piece supporting the queen to attack the King to threaten a mate or gain any material or positional advantage, infact after this white has to settle for a draw with perpetual checking which is...) 18...d6 19.Qg5+ Kh7 20. Qh4+ kg8 21.Qg5+
1/2-1/2. (If white wants to continue playing the position instead of perpetual, Black will have a slight advantage of around -0.4 and you can still play on with) 18...d6 19.Nb5( attacking pawn on d6) 19...f6 20.Nxd6 Nxd6 21.Rxd6 ( and the game goes on, though you have 3 pawns for his knight, after the exchange of queens and the other pieces at the right time, black with an extra knight will fight for the win, and white should play for a draw and achieving it shouldn't be hard. So instead of Bxh6, you could have just continued to play the position with 16.Be3 or 16.f3, white will have a good positional advantage)
16...Nd4?? (I don't know why your opponent played this, it just weakens his e5 pawn and does nothing else to defend white's Bxh6., black has totally worsen his position after this)
17.Rxd4 ( this is not a bad sacrifice, white still has the advantage of space, open king, isolated black pawns, 2 extra pawns for the exchange down, after this the way you carried on to play is fine because the endgame results you in a win, yes even if black hadn't given you the opportunity to mate him as you are 3 pawns up for the exchange, you can create passed pawns and black can do nothing to prevent the loss. But the best continuation than 17.Rxd4 which helps you to see the win right away was...) 17.Bxg7 (Completely opening the kingside, also gets back the sacrificing bishop which you will see in couple of moves) 17...Kxg7 (the best black can do, but still hopeless) 18.Qxe5 ( attacking the d4 knight and also threatening Qg5+. White gains the sacrifice back with a huge advantage even if black plays 18...Nc6 by playing 19.Qg5+ and then 20.Qxf6) 18...Qxc6 ( has to give up the d4 knight to defend the f6 knight which is the only defender around his king) 19.Qg5+ Kh8 20.Rxd4 ( White has huge advantage of two extra pawns, open black king, active rooks, space advantage, and can go on to achieve the win easily)


Fastest way to generate castling moves in a computer chess engine I am currently developing a Bitboard chess engine using C++. I am in the process of creating the move generator function. I have completed most of it and only the casting part is left.
I have used Magic Bitboards for sliding pieces and precalculated the attacks for other pieces. I am trying to make everything Highly efficient, by avoiding too many if-statements. The part I am stuck at is castling. The most naive method would be to use a few if-statements for checking whether the squares are empty and castling is still available. But this wouldn't be efficient at all.
What would be the fastest method to generate castle-moves?

It's been a long time since I've made any efficiency mods, but this can be reduced to one if statement, but many would be easier to read.
if
!bitboard_occupied  // easy to find by ORing with f1/g1 (or queenside)

!bitboard_attacked | [square e1/f1/g1 (or queenside)  // attacked already known

!bitboard_moved | (h1 (or a1) & e1)

Updating the moved bitboards would be more costly to maintain during each move and undo than the extra if statements in the relatively rare castling routine.


Finding a plan in the Archangels Spanish when white plays Be3 to exchange the dark-squared bishop Black to play and find a plan:

 [FEN ""]
 [StartFlipped "1"]
 [StartPly "25"]

 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O b5 6. Bb3 Bc5 7. c3 d6 8. h3 O-O 9. Qe2 Bb7 10. d3 Ne7 11. Be3 Bxe3 12. fxe3 Ng6 13. Nbd2

I often find myself in positions like this in blitz games and I think it's only a matter of time until it happens in a long OTB game. I know that I'm playing this wrong, but I couldn't figure out how to approach this position in general. Playing an early d5 is bad because it weakens c5 too much and gives white an excellent square for his knight on e4.

I tried using Stockfish to find a plan here, but it doesn't seem like the engine has a clue about what's going on. Sometimes it just moves about aimlessly and you cannot make out a plan. One move Stockfish suggests is 13. ... a5, followed by 14.a4 c6 and 15. ... Qb6, with the idea of getting play via the b-file. That all looks nice and good, but if white doesn't take on b5 and opens the b-file, black is just sitting there and doing nothing. So, I'm not really convinced yet. My question is thus two-fold:

What's black's best plan in this position?
Should I maybe avoid taking on e3 on move 11 to keep some more dynamic possibilities?

In the final position, the black pieces are pointed toward the king side, so logic says that you should attack there.  The two obstacles are the bishop pinning the f-pawn and the control provided by the doubled e-pawns.  Stockfish pushes the a-pawn to chase away the bishop and uses the queen to apply pressure on e3.

  Pressuring and exploiting white's dark-square weaknesses

I prefer the immediate d5.  This neutralizes the bishop and forces white to decide between exposing a weak pawn on d3, accepting the isolated and doubled e-pawns, or liquidating the center with d4.  It's possible to delay the d5 break with the restraining move c5.

  Quick d5 break: challenging white's light-square control & backward pawns.

On move 11.Be3, exchanging bishop seems to be the only move for black.  Allowing white to exchange ruins you pawn structure.  The weaknesses on e5 and c5 are greater than the exposed d3 pawn weakness.

  Trade of bishops on c5 leaves black with 2 weakened pawns.


What is the Colorado Gambit? I recently heard of an opening called the "Colorado Gambit". My chess opening is pretty weak and my friend suggested I might try it. What is Colorado Gambit and what is the reasoning behind the moves?

[FEN ""]

1. e4 Nc6 2. Nf3 f5?!

This is the Colorado Gambit.

If you are looking for a good solid opening, try looking up some of the following:

The Four Knights Game
Italian Game
The Ruy Lopez
The French Defence
The Sicilian Defence
Queens Gambit

This is more than enough for the beginning. All the best!


Stockfish depth calculations I'm using Stockfish to analyze my blunder filled games for blunders.
Let's say you send stockfish a FEN for a position and then calculate to a given depth ...
position fen the-starting-position
go depth 15

Now let's say a move has been made. I can either send stockfish the move...
position move the-move

or send it the fen that results from the new move.
position fen the-postition-after-the-move

Is Stockfish more efficient when you send it to the former?  That is, does it remember the evaluation from the starting position and use it as a starting point for analyzing the new position after you give it a 'position move ...' command?  And does it not remember the prior calculations if you just send it the next FEN in the sequences?

And a similar question.  If you tell Stockfish to analyze to a depth on a position, and then tell it to analyze to a deeper depth, does it start that second analysis from where the prior analysis stopped?
position fen the-starting-position
go depth 15
go depth 20

UCI protocol
Based on your answer, it looks like there is a typo and a misunderstanding.
The typo: It should be position ... moves, not position ... move.
The misunderstanding: The UCI protocol is stateless in the sense that you need to give the entire list of moves leading to the intended position every time, or the position itself.
Examples:

position startpos moves d1b1 is invalid, because d1b1 is not a legal move in the starting position.

position fen 3rr1k1/1b3p1p/6p1/pp1p3B/3N1P2/P3P2P/1p4P1/1R3RK1 b - - 1 28 is valid

position startpos moves e2e3 d7d6 d1f3 b8d7 f1c4 e7e6 d2d4 d6d5 c4d3 g8f6 c2c4 f8b4 c1d2 b4d2 b1d2 d5c4 d2c4 e8g8 c4e5 d7e5 d4e5 f6d5 f3e4 g7g6 g1f3 c7c6 e1g1 b7b5 a1d1 a7a5 a2a3 c8a6 f3d4 c6c5 d4c6 d8c7 e4d5 e6d5 c6d4 c7e5 d4f3 e5h5 h2h3 a6b7 d3e2 c5c4 f3d4 a8d8 e2f3 f8e8 f3h5 c4c3 f2f4 c3b2 d1b1 is valid and sets up the same position

position startpos moves e2e3 followed by position startpos moves d7d6 is invalid, because d7d6 is not a legal move in the starting position.

Differences between fen and moves
It's up to the engine if it can do something useful with the list of moves. For Stockfish, it's almost the same as not having the list, with no difference in efficiency. But having the list of moves informs Stockfish about possible repetitions, so it can avoid or aim for repeating an earlier position three times.