What are the things that a 2000 player knows that a 1800 player doesn't know? I'm stuck at 1600-1800 in chess.com. My rating fluctuates within that range. There must be something that I still don't understand that is already understood by a 1900-2000 player.

So I am asking for tips. How can I reach elo 2000? Should I focus on opening?

UPDATE
Thank you so much for the contributors. All answers are great and I really appreciate your efforts for sharing your ideas.

Should I focus on opening?

Do you regularly fail to get out of the opening? Regularly get beaten whilst still in the opening? If yes then you definitely need to work on your openings.

Do you usually come out of the opening with a playable position? If yes then you are wasting your time spending more time working on openings if your goal is to improve.

Do you get a lot of pleasure working on openings? I know I do and that's why I still waste time on them even though I know my time would be better spent on other things.

Once you get to something like 2300 then openings start to become a lot more important. At that level and above games are much more often won and lost on superior opening preparation, often geared towards a particular opponent and his known opening repertoire.

Twice in the last 15 years I've prepared a specific opening for a specific opponent and they've gone along and played what I wanted / prepared. In both cases the resulting position was what the book told me was a much better position for me. In one game it certainly looked that way because even though I was playing somebody about 100 points stronger than me I went on to win.

In the second case I again reached a position which was supposed to be better for me but I couldn't really see what to do and went on and lost. When I put the second game through the computer it didn't think much of the "much better position for me". So, you can't always trust the opening books. The top players, of course, are writing those books. Are they still playing? Are they really going to give away their best moves? Or save them for the next time they play Kramnik or Carlsen?

Bottom line: the effort v reward equation isn't very good. What I've been doing recently on openings is just making sure I have a repertoire which gets me safely to the middle game where the real fight at my / our level begins.

Here's another question for you. Can you mate with KNB v K? If not then I would strongly recommend that you study this endgame until you can win 100% of the time against the computer.

Now I know what you are going to say. "But I've never, ever had that endgame and I'll probably die without ever seeing it in real life" That's true. But the point of learning that particular endgame is that rounding up, corralling and then mating the opponent's king with just a bishop and knight requires remarkable co-ordination between your three pieces. The important thing you gain from mastering this endgame is not the ability to mate with KBN v K but the ability to co-ordinate king, bishops and knights in the endgame and this will come up a lot.

I remember years ago being very pleased to reach what looked like an even endgame where we each had king, knight, bishop and several pawns against a much stronger player. I offered a draw, as you do. He was very polite and didn't burst out laughing. After he'd beaten me he explained. "Look", he said, "No disrespect, but you are a much weaker player. This kind of position is actually quite difficult. Of course it should be a draw but I know how to play it and you probably don't. So, of course I played on."

Now, I could have just given you the standard reply of "Study endgames" but that wouldn't have really helped because it is too general.

Now, go away and learn how to mate with KBN v K. Practice until you can beat the computer 100% of the time and you will get a lot more points. Not only will you start drawing games you would previously have lost and winning games you would have let slip away to a draw but you will also recognize earlier in the game how you can steer the game to the kinds of positions you know how to play well in the ending and avoid ones which are not so good.


When is it considered a win vs a draw? I am playing with black and have just called check on the white king. It is now the white players turn, no matter what move the white king makes it will lead to check. Does this mean black has won or is it considered a draw?
[fen "r5nR/p2b4/npp1pk2/3p3Q/P2P1p2/R1P1qP1N/1P2PKB1/8 w - - 0 1"]

This position leads to a threefold repetition (which is a DRAW), as White can move the King to e1/f1 and ...Qc1+ forces the King back to f2, where ...Qe3+ forces the King back again.
As Black is material down and has no compensation, Black should force the draw by repetition.
 [FEN "r5nR/p2b4/npp1pk2/3p3Q/P2P1p2/R1P1qP1N/1P2PKB1/8 w - - 0 1"]

 1. Ke1 Qc1+ Kf2 Qe3+ Kf1 Qc1+ Kf2 Qe3+


Is there a single best move in every position? If it were possible to analyse every possible outcome of a position, would there ever be a single move that could be considered "best"?

I know that this is how computers evaluate positions, but they can only calculate the decision tree down to a set number of moves. If it were possible to analyse every possible outcome in a reasonable amount of time (possibly with quantum computing), could the ultimate chess move be made?

What I guess I'm saying is that is a chess move objective in that only one move is really the best one, or should it be subjective in that it makes certain assumptions about the opponent? For example a move may be made that 90% of players are not "good enough" to counter, and therefore that move was a good move (what I mean by subjective). However, there may be another move that is more strategic which increases the chances of victory against 100% of players, but this would not be known to anyone unless it was possible to make an exhaustive analysis of every single outcome (objective).

No, there are positions in which a lot of moves have the same effect or are the same but you can play them in a different order.


How can I find games from grandmasters that end in threefold repetition? When I go to http://www.chessgames.com/, I can search for matches that end in draws. However, I can not figure out how to filter those draws to specifically threefold repetition. How can I find these types of draws while filtering out the rest?

If you have a collection of games in PGN format, you could probably search for threefold repetitions using the Chess Query Language. In particular, you might look in the "Matching positions: the position list" portion of the manual at the provided link; the :sequence keyword would likely be instrumental to a CQL solution.

For an example of using CQL to do this sort of thing, see my answer to an earlier question about seeking out exchange sacrifices in games. The method given there uses CQL to scan games for short sequences of successive positions that have a material difference of an exchange. I imagine you'd be able to do something similar to seek out sequences of positions repeating three times.


How can one claim 50 move rule draw under time pressure? Suppose one player has only 3 minutes of time left in his clock. The position is a draw with opposite colored bishops and neither player can break forward practically. The other player, who has got lots of time left, intentionally plays on to win on time. Since the player under time pressure will not be keeping score, how can he claim if he has completed 50 moves as per the 50 move rule? What is the best solution to this situation in a tournament organized according to FIDE rules?

According to clause 8.5a of the FIDE Laws of Chess (the URL keeps changing so I won't link to it, but you can search), if a player has under five minutes left and the increment is less than 30 seconds per move (or nonexistent), an arbiter or assistant should keep score if possible. This is one reason that a 30-second increment is used these days; both players are required to keep score for the whole game so this situation never comes up.

If the game is played by USCF rules, then according to rule 14F4, if a player has under than five minutes left, he can ask the tournament director to keep track of the number of moves in order to verify a claim that the player makes. (The player is still responsible for making the claim.)


Ideas for the English opening I'm playing recently the English opening. specifically this line in the two knights variations

[FEN ""]
1.c4 e5 2.Nc3 Nf6 3.g3 Nc6 4.Bg2

But I find it difficult to see when it's advantageous to go queen side with a3 b4 idea rather then play in the center with e3 maybe d4 later on.

Any thoughts ?

This is a tough question and depends a lot on where the f8 Bishop is going (b4, c5, e7, or even g7), as well as where is the Knight g1 is going (e2 or f3).

In the position of the diagram the most common move among top players is 4...Bc5. Then after 5.e3 with the idea to place the Knight g1 in e2 and to control the square d5 with the Bishop in g2, Black can still react by temporarily sacrificing a pawn with 5...d5 6.cxd5 Nb4 and a wild game. If Black prefers a more positional battle with 4...Bc5 5.e3 a6, then White prefers to expand on the queen-side: 6.Cge2 a6 7.0-0 0-0 8.a3 Ba7 9.b4 with a very flexible play.

Check this nice game between Nakamura and Grandelius at Gibraltar in 2015 (even if the move order is more subtle)


Why are Leela's fans so passionate? The neural-network engine Leela is a relatively new one. It's also got some extremely passionate fans. For example they write things like this:

  Wait 5-6 months, and we will see SF8 on uber-duper logarithmic in cores Elo-wise 32 cores being smashed by Lc0 on my puny single 1060.

Watching Leela's fans argue up and down Talkchess, Chess.com's computer championship chat and TCEC chat, about how their engine is / isn't superior to Stockfish because of [multitude of factors] or how their engine is going to crush Stockfish after the next learning rate drop, about how the "end of an era" is at hand, etc, makes me wonder: why are Leela's fans so passionate?

I don't recall seeing anything similar to this before Leela showed up. It's not like Leela is so special either: before Leela showed up, Stockfish, Komodo and Houdini dominated engine chess, and there were periods when any of the three were the strongest engine. But I don't recall seeing any of their fans displaying the same level of intensity.

You can't really objectively answer this question, but I'll share my view.

One of the important factors to take into account is that Leela Chess Zero project requires tremendous computational resources to complete. The way project attains those resources is by convincing large number of people to donate part of their machine time to that project.

To make this work, project needs to sustain strong community that clearly sees its goals, ideas and progress. There have been done many things for that: there is a very active discord chat, google groups, blog, you can see lots of graphs and metrics regarding project status, there are very detailed spreadsheets, etc. Also some chess youtubers helped this project grow community (e.g. KingsCrusher and ChessNetwork) by featuring it in their videos.

Beating StockFish is one of the very important goals of this community.

When people are united around some idea, it's because they are passionate about it. The behavior you are describing looks the same as when people argue about politics, football, religion, nationality, etc.


Overprotection Of A Piece What exactly is the logic behind the concept of “overprotection of a piece”?

Wikipedia says that it "...provides greater freedom of movement for the pieces protecting that square."  If the protected pieces moves, then one of the protecting pieces leaves and that seems like it goes against the concept. What is the actual logic?

From the cited Wikipedia article:

  The strategy of protecting a pawn or specific square of the chessboard more than is immediately necessary. This serves to dissuade the opponent from attacking that specific point and provides greater freedom of movement for the pieces protecting that square.

The sense in which overprotection provides "greater freedom of movement for the pieces protecting that square" is that, with multiple defenders already in place, no one of them is necessarily tied down to defense.

What follows isn't the greatest example, but I think it illustrates the concept fairly well. (I'm not claiming any of these moves are the best or are necessary; I've chosen them specifically to illustrate overprotection.)

[FEN "r1bq1rk1/ppp1npbp/3p1np1/4p3/2P5/2NPP1PP/PP2NPB1/R1BQ1RK1 w - - 0 1"]

1.Kh2
    {Overprotecting h3, and thus creating a genuine threat against b7 by
    the Bg2. That makes it so that the Bc8 can't develop immediately.}
    ( 1.Rb1 {In this variation White leaves the Bg2 as the only defender
    of h3, and so Black can immediately develop the Bc8 if she likes.}
    1...Be6 2.Bxb7 Bxh3 3.Bxa8 Qxa8 4.e4 Bxf1 5.Qxf1 )
1...Rb8
    {Black responds by overprotecting b7 herself. Again, having this
    second defender frees the Bc8 to develop.}
    ( 1...Be6 $2 2.Bxb7 )
2.Rb1 Be6

The Wikipedia entry continues:

  [Overprotection] can cause an opponent to pursue a faulty plan or no plan at all.

I'm not sure about that wording, but I think the intended meaning is this: the opponent might press on against the overprotected piece/square in what will be a futile attempt thanks to the overprotection (faulty plan) or will be forced to abandon that endeavor and look for something else to do (no plan at all).

For example, in the basic structure of my position above, it is very common for Black to line up a Be6 and Qd7 to harass the h3 pawn (or just try to trade off the light-square bishops if the pawn is still on h2); but once White has played h3 and Kh2 as above, Black won't really be able to effect that plan. She might press on and ultimately be unsuccessful (faulty plan), or instead need to figure out something else to do in the position (no plan).


Swiss-pairing algorithm Is there a (simple) algorithm for setting up a swiss tournament? I've searched around a little, but can't find anything specific.

Alternatively, is there any good and free software available for setting up swiss tournaments? All of those I've tried have very few options and little functionality available.

is there any good and free software available for setting up swiss
  tournaments? All of those I've tried have very few options and little
  functionality available.

Vega is a swiss pairing program which has been approved by FIDE. It is free if you install it on Linux and if you install it on Windows it is free up to 30 players in the tournament. It is a lot more user friendly than other programs you have to pay for and is excellent for amateur use.

The only drawbacks for professional use are the 30 player limit if used on Windows and the lack of a website for publishing the pairings and results. The program allows you to prepare HTML files for uploading to your own (or the tournament) website but it does not come with a standalone website like Chess-results.com which comes with Swiss Manager.


Cmail/XBoard won't allow move I've recently started playing e-mail correspondence chess and I'm looking at Cmail/XBoard as a tool to play these games. Looking at the docs, I managed to get the right PGN tags for the game to be parsed and XBoard to launch and display the latest position.

XBoard will not allow any moves though. I can step through the game but not enter a new move.

Any idea on what could be wrong with the XBoard settings or the PGN input?

[Event "Email correspondence game"]
[Site "NET"]
[Date "2016.08.04"]
[Round "-"]
[White "Vergara, Rene"]
[Black "?"]
[Result "*"]
[WhiteNA "?"]
[BlackNA "email@host.com"]
[Mode "EM"]
[CmailGameName "rav-vs-Rene"]

1. e4
*

Once you provide the email file to Cmail/XBoard, you need to switch to 'Edit Game' mode, in the Mode menu in order to record a move. Also, I had to switch out of 'Edit Game' mode in order to mail the move.


What is the best way to play chess via terminal? I've recently learned about gnu chess, but it's poorly documented, and I'm having difficulties:

Setting a reasonable difficulty level;
Saving an entire game to a pgn: it's only saving the last move;

How can I do this?
Is there an e-book or a good tutorial I can follow?

Thanks in advance

Update (2/8/15):  Actually,  it's the version of gnuchess that's packaged with Debian 7 (6.0.2) that has a bug; after compiling 6.2.1 pgnsave worked normally.

You can save games with:

pgnsave FILENAME

This saves the game played so far from memory to a file.

You can find some documentation here: http://savannah.gnu.org/projects/chess/


How bad of a chess player was Alan Turing? It is interesting that Turing worked with some of the best British chess players among them Golombek and Alexander. I am not sure how to characterize it, but he is considered a creative genius at a level and was certainly very important and successful in the code-breaking efforts during WW2.
He would play with Golombek, who I think could allow Turing to change color at a point of his choosing during the game. Although, I am not sure of the constraints; maybe it was up to a certain move. Golombek could then beat Turing from Turing's presumably losing position. I have never played at those odds, but I can't imagine, assuming that Golombek was playing to win, that Turing had much of a position, to begin with. On the other hand, perhaps, Golombek would try to keep a more or less even game so that he had chances. Anyway, I really wonder how weak of a player Turing was and if perhaps some of his games survive.

A similar question was asked on another forum a few years ago, and the answer that was given was "Alan Turing wasn’t a very strong chess player at all. He was probably at the level of a beginner. He certainly knew the rules of the game, but not much more."

Wikipedia notes, regarding the chess program that Turing and a colleague designed, "... the algorithm is primarily designed around the decision to take a piece or not; according to Turing, the resulting gameplay produces a low level game of chess, which he considered commensurate with his self-described average skill level at the game."  According to the article, Turing's algorithm (it's really difficult to call it a "program", as it never ran on any actual computer - Turning only ever "ran" it on pencil and paper) only looked two half-moves ahead, applied a static evaluation function to each resulting position, and selected as the next move whichever one led to the highest average evaluation after the following half-move.


Is it possible for stockfish to tell that mate is in X moves, when mate is in X + Y moves? I know that it is possible for a chess engine to evaluate a position as mate in X moves, when in fact there exist a mate in smaller number of moves. But can the reverse situation happen?

For example the engine evaluated a position as mate in 8 moves, but actually the best possible mate is in 9 moves (or 10 or 13).

To be more concrete the engine is stockfish.

No, it isn't possible because, before Stockfish says it is Mate in 8, it views the position from the aspect of the losing side, i.e, the evaluation is the best that can be obtained by the losing side.

In other words, Mate in 8 is what happens if the losing side plays the possibly best defense. If the losing side plays sub-optimally, it could lose faster, but 8 moves is the longest possible postponement of Checkmate


PythonChess - Get engine to predict a list of the best moves in a position Say that I currently have a board, and then on that board I move my e2 pawn to e4. I'm looking for a way to get the engine to predict the X amount of best moves for black.

I know how to predict the best move given a position:

result = engine.play(board, chess.engine.Limit(time=0.1))
board.push(result.move)

But that only predicts the number 1 best move. I want a list containing the second, third ... X best moves.

How would I do that?

In the world of chess engines, what you're looking for is called multi-PV (multiple principal variations): telling the engine to look for and return up to n best moves and the associated principal variations for each. ("Up to" because sometimes there's only 1 legal move in a position.)

In python-chess, this is part of the engine protocols, as one of the optional parameters when calling engine.analyse(). From the documentation:

  class chess.engine.EngineProtocol

  coroutine analyse( [...] )

  multipv – Optional. Analyse multiple root moves. Will return a list of at most multipv dictionaries rather than just a single info dictionary.

The .analyse() method tells the engine to analyse the position, returning a dictionary of information, which includes among other things the moves of the principal variation. Specifying for instance .analyse(multipv = 3) will tell the engine to return a list of (up to) 3 such dictionaries -- the first moves in the pv value of each dictionary should be what you are looking for.


Safe place online for children to play against others I'm looking for a safe website where my child can play. He is developing his game, I'm worried about people he may meet on various websites.
If there are some known places please advise.

The free online chess site Lichess offers a feature called "kid mode".
I haven't tried it out myself, but when enabled, all site communication features are disabled while the rest of the site remains functional.
It's password protected and can be enabled under Preferences → Kid Mode:


Scid vs Mac game interrupted My Windows 7 Bootcamp partition failed me, so I'm using Scid vs Mac OSX 10.9.5 app to test my engine. It works fine, but sometimes a tournament game is 'interrupted' and I don't know why. For example, in this game my engine was playing white:

1.e4 e5 2.Nf3 Nf6 3.Nxe5 Nxe4 4.Qe2 d6 5.Nxf7 Kxf7 6.Qxe4 d5 7.Qf3+ Kg8 8.Nc3 Be6 9.Qe3 Qf6 10.Nb5 Na6 11.Kd1 Bf7 12.d4 c6 13.Nc3 Nb4 14.a3 Re8 15.Qd2 Bh5+ 16.Be2 Bxe2+ 17.Nxe2 Na6 18.Qf4 Be7 19.Re1 Bd8 20.Be3 Qg6 21.Qg3 Qf5 22.Kc1 Bc7 23.f4 Kf7 24.Qf2 Rhf8 25.Ng3 Qg4 26.h3 Qh4 27.Ne2 Qxf2 28.Bxf2 Bd6 29.Bg3 Nc7 30.Kd1 Re4 31.Ra2 Rfe8 32.c3 c5 33.dxc5 Bxc5 34.f5 Nb5 35.a4 Nd6 36.b4 Nxf5 37.Rf1 Ke6 38.Rxf5 Kxf5 39.bxc5 Re3 40.Bf2 Rd3+ 41.Kc1 Kf6 42.Bd4+ Kf5 43.Bxg7 Rg8
White movetime 0.033 secs

We see this message: "White movetime 0.033 secs". What does that mean?

I find out that my UCI protocol parsing had some nasty bugs, that's why all the Perft tests were ok, but the engine matches were buggy... ouch!

So it was not SCID's fault, sorry!


Exchanged Slav defense. Gambit the c6 pawn. Why not? [Update:] It's called "Tan gambit" after an Alekhine game. Analyzed below. White should dicline the pawn, since. It can be played as a drawing line for black (no queens).

d4 d5 2. c4 c6 3. cxd5 Nf6!?

This seem to me a good gambit line. I think it's a good way of playing but no one does according to www.365chess.com Some people find exchange variation boring. What is the reason that no one is playing it?

Take a look at the position after 1. d4 d5 2. c4 c6 3. cxd5 Nf6 4. dxc6 Nxc6 5. Nf3 Bg4 6. e3 e5. Black is very active.

Of course white can avoid it by 3.Nf3. Meaning that slav players still have to know the exchange variation. A gambit does not need to be 100% correct. But a gambit no one is playing?

(I found it via 1.d4 d5 2. c4 Nf6. With no one I don't mean 0).

[FEN ""]

1. d4 d5 2. c4 c6 3. cxd5 Nf6!? (3. cxd5 cxd5) (3. cxd5 Nf6 4. dxc6 Nxc6 5. Nf3 Bg4 6. e3 e5)

[Update]: I used lichess (poor) analysis feature to analyze some games. [Between strong players].

Nf3 Bg4. [What I would play].

7. Be2 [What I would be most afraid of]. ½-½, Reinhold (2139) vs. Stevermueer (2150)

7. Bb5 [Messy internet game] 0-1, Drozdovskij (2509) vs. Dobrov (2515)

Nf3 e5. [Queens are exchanged].

6. dxe5 1-0, Sandipan (2637) vs. Elorta (2363)

6. Nxe5 ½-½, Vorobiov (2577) vs. Zvjaginsev (2646)

Nf3 Bf5.

5. Nf3 Bf5 1-0, Alekhine vs Tan

In the chessok opening tree there are 28 games with this gambit. Going by the computer evaluation it seems to be playable, but the score is atrocious (>80% for white).

So here you have a gambit that is pretty unknown, scores horribly and can easily be ignored if white is not in a mood for adventures. Also it doesn't seem to lead to dangerous complications as far as I can see. There is no automatic attack on the white king, in the worst case white just returns the pawn.

All in all not very surprising that it is rarely played.


FIDE World Champions after 1993 Are FIDE World Champions after the 1993 Kasparov-Short match, i.e. Khalifman, Ponomariov, Kasymdžanov, Topalov, (not counting Karpov and Anand, for obvious reasons) to be considered actual World Champions, or not? I think that the real World Champions after Kasparov are Kramnik (who beat Kasparov), then Anand, and of course Carlsen. What's the chess world's view on this?

The answer is that both the FIDE world champions and the PCA world champions were world champions.

The situation was actually less chaotic than the normal situation in boxing. In boxing there are four bodies awarding world champion titles. They are -

WBA - World Boxing Association
WBC - World Boxing Council
IBF - International Boxing Federation
WBO - World Boxing Organization

In the heavyweight division the British fighter, Anthony Joshua, holds three of the four titles (WBA, IBF, WBO) but in the light heavyweight division four different boxers hold the four titles -

WBA - Dmitry Bivol
WBC - Oleksandr Gvozdyk
IBF - Artur Beterbiev
WBO - Sergey Kovalev

If boxers are clever enough to get their heads round having up to four different world champions in one weight division then I'm sure chess players are clever enough to manage just two for the short period of time of the existence of the PCA.


Why should black trade knights in this position? After playing the following game, Stockfish advised me to play ...Nxd2 after white played Nd2 (which I did not play during the game).
However, I am not sure why. Certainly, in the worst case, this is just an even exchange of material.
But is there any point in that move beyond that? Wouldn't moving the knight back to g5 be better as it controls the center?
[fen "r1bqkb1r/ppp1pppp/2n5/8/3Pn3/2P5/PP1N2PP/R1BQKBNR b KQkq - 2 6"]

Computers have complex reasons for their move choices, however, in this position there is a simple rationale for exchanging knights.
You need to think of two factors: are pieces moving to better (or worse) squares, and tempo (who is to move).
In this position, if you play Nxd2, White gets to play Bxd2. So, you keep the move and White improves his bishop slightly and opens C1 for the rook. If you move the knight to f6, then nobody improves, but you lose the move. Note that you cannot play Ng5 because of h4.
In this position losing tempo would be less desirable because White can use his move to play Ngf3 which stops you from playing e5! which is the key move in this position. If you keep tempo, then you can play 1...Nxd2 2. Bxd2 e5! This will improve your position by allowing you to challenge the center.
If you play Nf6 and White stops e5 by playing Ngf3, then White definitely has the advantage because of having more places to put his pieces by virtue of controlling the center. You could easily find yourself in a lost position if White continues to dominate the center.


What different time control rules are there in chess tournaments? I am trying to find all possible time control rules that are used in various tournaments (not only regular chess, but also speed chess).

For example on one of the website I am using the following time controls are available:

10sec + 1 sec
1 min
1 min + 1 sec
...
10 min
...
30 min
60 min

Is there any list of chess control rules for rated tournaments (normal or blitz)?

The FIDE-approved classical time control is: (taken from the handbook)

07 Time Control
There is a single time control for all major FIDE events: 90 minutes for the first 40 moves followed by 30 minutes for the rest of the game with an addition of 30 seconds per move starting from move one.

This time control is used in many major chess events such as the Olympiad, FIDE Grand Prix and World Cup.

Another popular international time control for classical is 90 minutes with a 30 second increment.

The classical time control used in the World chess Championship is: (from Wikipedia)
120 minutes, with 60 minutes added after move 40, 15 minutes added after move 60, and 30 additional seconds per move starting from move 61

Blitz time controls is simpler, with just two that dominate tournaments.

3 minutes with a 2 second increment is very popular in top level tournaments, being used in the recent World Blitz chess Championships and most, if not all the top level blitz events, this is because FIDE wants to avoid wins on time, to preserve the quality of top-level chess and also because there are significant prize funds at stake.

5 minutes is the most popular however, as it is easier to schedule as the games can only go as long as 10 minutes, whilst with an increment in can take a while.

For Rapid

15+10 (15 minutes with a 10 second increment) was the time control used in the recently concluded FIDE World Rapid and Blitz chess Championships.

25+10 Is very popular in top level rapid chess and all around as well, it was used in the World Cup in 2013 for the rapid tiebreak stage.

25 This is the most popular for the same reasons as 5 is for blitz.

This is for the rest of the world.

For the United States, its a whole different story,

http://archive.uschess.org/ratings/info/time.html


Predicting color and opponent Is there any way to predict, with some certainty, my next opponent and color for next round in a swiss tournement on chess-result:
http://chess-results.com/tnr406767.aspx?lan=1

One sure-fire way is for you to buy your own copy of Swiss Manager, the pairing software used in this particular case, and reproduce the tournament and then do the next round pairing once all the results are in. The light version of Swiss Manager, which you could use since there are fewer than 60 players, costs 75 euros.

Alternatively you could try and do the pairing by hand yourself. For this you would need to read, understand and follow the FIDE Swiss rules for pairing.


How do chess engines decide which best line to play when the game outcome is within their horizon? Inspired by the Hot Network Question "In this puzzle, why does white play dxe5?", when a chess engine is in a position that it can definitively call lost, drawn, or won, what policy is used to decide among lines that lead to the same outcome?

In a won position, the answer seems easy: play the line that leads to checkmate fastest.  But in a lost or drawn position, the engine's opponent may not realize the situation, so it should continue fighting, ideally playing a complicated line and setting traps in hopes of swindling a draw or win.  But it is not clear to me how the code could identify such a line from a game tree and evaluation scores alone.

(In a game with time controls, the answer may be more complicated; I am okay with an answer that ignores considerations of time pressure.)

If the engine can choose between getting mated in 2 or mated in 3, it'll choose the line where it is mated in 3 (even though the mate in 2 might be 'more difficult' to spot for humans).

It can't really set traps, because it doesn't know what things might be difficult to spot for a human (or other engine) opponent. It just evaluates the position, without really knowing it's playing a game against somebody; a notable exception is the implementation of contempt, basically a slight modification of the evaluation in order to prevent drawing too early.

For example, in Stockfish, scores for won or lost positions are computed with the function mated_in (and, more rarely, its negated form mate_in).  As you can see in the code, a loss is scored as a large negative value plus the number of ply until the loss, so the engine favors winning lines that are fast and losing lines that are slow.

The tie-breaking for draws is usually arbitrary.  For instance, in Stockfish, scores for drawn positions are either the constant VALUE_DRAW or computed by the function value_draw to be VALUE_DRAW plus one or plus two.  The bonus depends on the thread's node counter, which is essentially up to luck, so the variations in scores for drawn positions are not really based on the positions themselves.  This small bit of noise in draw scoring is more to keep the search from fixating on certain three-fold repetitions than to help it choose among lines.


What is Berg's counter-attack system? Chessbase published an article today about the "World Prestigious University Chess Invitational Tournament" which includes this line:

  The tournament will use the Berg's counter-attack system, and will be ranked after eleven rounds in five days. Each team shall comprise three players (two men and one woman), one captain, and one coach. The time control is 25 minutes plus 15 seconds per move.

What is Berg's counter-attack system? I tried searching for it, but didn't find anything.

From the article:

  The participants are listed here in the order of registration:

  The united team of Japan Universities
  Moscow State University
  University of Missouri
  University of New South Wales
  University College London
  Harvard University
  Princeton University
  University of Toronto
  Saint Louis University (two teams)
  University of Oxford
  Nankai University of China (Host team)

So, 11 teams. For an all-play-all that would require 11 rounds where one team has a bye in each round.

The article goes on to say:

  The tournament will use the Berg's counter-attack system, and will be
  ranked after eleven rounds in five days.

So, yes, 11 rounds. The standard way of pairing such a tournament would be to use the Berger tables. The FIDE Arbiters Commission publishes an Arbiter's Handbook which, amongst a lot of other information, includes a section which lists the Berger pairing tables for various numbers of players. The table for 11 or 12 players is given on page 66:

  11 or 12 players:
  Rd 1: 1-12, 2-11, 3-10, 4-9, 5-8, 6-7.
  Rd 2: 12-7, 8-6, 9-5, 10-4, 11-3, 1-2.
  Rd 3: 2-12, 3-1, 4-11, 5-10, 6-9, 7-8.
  Rd 4: 12-8, 9-7, 10-6, 11-5, 1-4, 2-3.
  Rd 5: 3-12, 4-2, 5-1, 6-11, 7-10, 8-9.
  Rd 6: 12-9, 10-8, 11-7, 1-6, 2-5, 3-4.
  Rd 7: 4-12, 5-3, 6-2, 7-1, 8-11, 9-10.
  Rd 8: 12-10, 11-9, 1-8, 2-7, 3-6, 4-5.
  Rd 9: 5-12, 6-4, 7-3, 8-2, 9-1, 10-11.
  Rd 10: 12-11, 1-10, 2-9, 3-8, 4-7, 5-6.
  Rd 11: 6-12, 7-5, 8-4, 9-3, 10-2, 11-1.

"Berg's counter-attack system" looks like a 3rd rate Google translation. I susupect this article was given to chessbase and they included it without any checking. It is not "Berg's counter-attack system" it should be "Berger pairing table".


Does 1. e4 e5 2. Nf3 f6 have to be a bad opening? There seems to be a pretty nifty attack for White after  1.e4 e5 2.Nf3 f6:

[FEN ""]

1.e4 e5 2.Nf3 f6 3.Nxe5 fxe5 4.Qh5+ g6 5.Qxe5+ Qe7 6.Qxh8

I've played as White with this opening several times, always to my advantage (usually Black panics and plays 4 ... Ke7, soon after which he finds ample reason to resign).  But once someone played as shown above, and went on with

6. ...     Nf6,
  etc.

to try and put my queen on the spot.  Presumably he intended to follow up with moves such as ...b6, ...Bb7 or similar, ...Nc3 or similar, ...O-O-O, and then ...Bg7 forcing Qxd8.  Since it was a blitz game, best play was not made, and he made a mistake allowing my queen to escape, but it got me thinking.  Is there some way Black can recover from 1. e4 e5 2. Nf3 f6?

My question especially regards 1. e4 e5 2. Nf3 f6 3. Nxe5 fxe5 4. Qh5+ g6 5. Qxe5+ Qe7 6. Qxh8 (as shown above) - is there a way to trap White's Q?  Or is 3... fxe5 simply a bad move?  Should 2... f6 be avoided altogether?

After

1.e4 e5 2.Nf3 f6 3.Nxe5 fxe5 4.Qh5+ g6 5.Qxe5+ Qe7 6.Qxh8 Nf6

with ideas of trapping the queen, 7. d3 followed by Bg5 or Bh6 and there won't be any issues getting the queen out, e.g.:

7.d3 d5 8.Bg5 Nbd7 9.Nc3 b6 10.0-0-0 Bb7 11.e5

Black can try to minimize the damage after 2...f6? with something like 3.Nxe5 Qe7

You aren't losing the exchange any more, but you've still destroyed your position with ...f6.

2... f6 should be avoided.


What are the rules around talking/ communicating during a chess game? I heard in a youtube video that you are not allowed to talk to your opponent unless you are saying check or checkmate. Obviously, this rule is loosely enforced in casual play, but is this true?

According to the FIDE Laws of Chess, rule 11.5:

  It is forbidden to distract or annoy the opponent in any manner whatsoever. This includes unreasonable claims, unreasonable offers of a draw or the introduction of a source of noise into the playing area.

So you can't just say whatever you like to your opponent while you're playing an official game. It's distracting, both to your opponent and to anyone else trying to play in the room.

Check or checkmate is not the only thing you can say, however (and at high levels, almost nobody says check.) Obviously, you're allowed to point out that the game is over because the position is drawn by rule or one player is out of time. A draw offer is ordinarily spoken aloud. You must also say something like “j’adoube” or “I adjust” when adjusting a piece. In USCF matches, I've generally told my opponent if they make an illegal move, so they can correct it, rather than stopping the clock and summoning the tournament director. I've also quietly pointed out some other rules to my opponent when they came up, such as if they touched a piece and then moved a different piece.


What's the best move against this variation in the Philidor Defense? What's the best Knight move for White against this variation (loved by beginners) in the Philidor Defense?

[FEN ""]
1. e4 e5 2. Nf3 d6 3. d4 exd4 4. Nxd4 c5

As Ian Bush already mentioned in a comment, 5.Bb5+ is arguably the strongest reply. After 5....Nd7 6.Nf5 or 5....Bd7 6.Bxd7+ Qxd7 7.Nf5, black has some serious problems with the weak pawn on d6 and square d5.
Note that there are some similarities with a line in the Sicilian: 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 e5 5.Bb5+.

Other moves are less convincing. After 5.Nf5 Nf6 or 5.Nb5 a6 6.N5c3 Nf6, black is probably fine. 5.Nf3 is not a bad move, but it doesn't take advantage of black's weaknesses.

      [FEN ""]
      [StartPly "1"]

      1.e4 (1...c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 e5 5.Bb5+) e5 2.Nf3 d6 3.d4 exd4 4.Nxd4 c5 5.Bb5+ (5.Nf5 Nf6) (5.Nb5 a6 6.N5c3 Nf6) (5.Nf3) Bd7 (5...Nd7 6.Nf5) 6.Bxd7+ Qxd7 7.Nf5


Which chess openings trade the most pieces? The goal here, albeit heterodox, is to bring the game into a position with few pieces on the board, where yourself as a player has forced the other to trade all your major pieces, leaving both in a position that is likely to draw.

Which chess openings illustrate this strategy best?

in the gurgenidze variation of the accelerated dragon, all pieces are exchanged off except white's two bishops, and typically a bishop and a knight for black. white has a nice space advantage, but blacks structure is very solid and he should be able to draw. however, there are no winning chances for black.


Why do masters open 1.d4 more often than 1.c4? Why do masters open 1.d4 more often than they open with the English 1.c4?

STATISTICS

According to 365chess.com, 1.d4 is five times as common. Moreover, even if one admits Réti's 1.Nf3 as an English variant (or vice versa), counting Réti and the English together as a single opening family, 1.d4 remains twice as common.

According to the aforementioned source, in master play, White scores slightly better (though indeed almost exactly the same) with 1.c4 as with 1.d4. Réti's 1.Nf3 fares slightly worse.

MOTIVE

I ask because, in my own games, the English opening wins for White more than 1.d4 does. That is, I win more with 1.c4 as White and, as Black, probably lose more when 1.c4 is played against me. My strength being a little below FIDE 1300, my games would hardly interest you, so I will refrain from burdening the question with patzer's samples of my own play. However, if the statistics are credited, masters perceive comparative virtues in 1.d4 I do not yet see; whereas, from my limited perspective, 1.c4 just looks like the better move insofar as it leaves Black with three main options that all seem slightly weak:

Black can let White play a reversed Sicilian, granting an extra tempo to the reversed Sicilian queenside attack;
Black can transpose to a Queen's Gambit Declined or a Slav, only with fewer options for Black; or
Black can symmetrically play 1...c5, allowing White the advantages symmetrical openings generally bring.

A fourth option occurs:

Black can respond to 1.c4 by playing one of the Indian systems. This seems no weaker than playing Indian against 1.d4 but, as far as I can see, seems no stronger, either.

I can see that 1.d4 is not a bad move, but isn't 1.c4 just a better one?

A GRANDMASTER'S OPINION

Paul van der Sterren, a grandmaster, writes that 1.c4 and 1.Nf3 "betray a rather more moderate attitude [than does 1.d4]. While not as yet physically occupying any central squares, White does start taking control over them. White prepares for a fight in the center but does not want to be the one to take the first step."

Van der Sterren writes as though the factors he mentions might be disadvantages. Are they disadvantages, though? And how moderate is 1.c4, really? In my limited experience, 1.c4 seems fairly aggressive in actual play—more aggressive than the Ruy Lopez, for example, at least in games I play.

Of course, the grandmaster will be right and the patzer (me) must be wrong, but for what reason?

Indeed, why do masters open 1.d4 more often than 1.c4?

This has nothing to do with 1.d4 being an objectively better move than 1.c4. The moves are just about as good as one another, and sometimes even transpose as you've noted.

But 1.d4 was historically considered to be one of the two best opening moves (together with 1.e4) for a very long time, and it is more in line with the basic opening principles that beginners are typically taught.

So I'd reckon that it comes down to more players being introduced to 1.d4 early on in their chess career than 1.c4, coupled with the fact that old habits die hard (even for chessplayers).

However, one point that speaks in favour for 1.d4 over 1.c4 is that 1.d4 hinders black from playing 1...e5. You've noted that 1.c4, e5 is a reverse Sicilian, but I think that it is important to remember that the Sicilian is an opening that Black chooses to enter. In the opening Black is fighting for equality, and this is the case for the Sicilian as well, so saying that 1.c4, e5 is an improved version of it for White is basically just another way of saying that White is fighting for an advantage when playing it. But this is just what you'd expect from any good opening for White.

I'd go so far as to say that this way of arguing for a move is a fallacy in some sense, since it could be used to try and justify almost any first move for White as the best one (for instance, 1.Nf3 must be very strong since 1.Nf3, d5 is a reverse Nimzo/King's/Queen's/Bogo/whatever Indian defence and thus comes with an extra tempo as compared with the normal Indian defences, which are considered to be good for black). I'm almost tempted to name this way of  reasoning "The Reverse Sicilian Fallacy" for future use, since I've seen it more than once when commentators try to describe the virtues of 1.c4.


Most different openings by transpositions? What sequence of opening moves can include most different named Openings or Defenses by transpositions?

For example, I just played a bullet game that went:

1.d4 e5 2. e4 d6 3. Nf3 Nc6 4. Bb5.

In this sequence, we have, in just four moves:

Queen’s Pawn Opening;
Englund Gambit;
King’s Pawn Opening;
Center Game;
Philidor’s Defense;
Ruy Lopez;
Steinitz Defense to the Ruy Lopez;

Very interesting is also:

1.e4 d5 2.d4 c6 (or 2...e6), and so on.

Are there any other similar (or better) examples of this kind?

Another well-known example is the following:

[fen ""]
1. f4 {Bird's Opening} 1... e5 {From Gambit} 2. e4 {King's Gambit} 2... d5 {Falkbeer Counter Gambit} 3. exd5 exf4 {King's Gambit Accepted}

A total of 5 distinct names.
Bird's Opening
From Gambit
King's Gambit
Falkbeer Counter Gambit
King's Gambit Accepted


Slav - Theory Heavy Book I have come to the realization that studying opening theory is far and away my favorite aspect of chess.

That being said I am looking for a comprehensive theory heavy book on the Slav. I would like one that deals with pawn structure formations, middle game plans, and potentially end games that occur frequently. I would also like one that deals with the subtleties of move order as sometimes that is glossed over in books that are rushed to be published. Any help would be greatly appreciated.

Looking for something aimed at the 2000+ level

http://www.amazon.com/Grandmaster-Repertoire-17-Classical-Slav/dp/1907982388

Grandmaster Repertoire 17 by Avrukh is probably what you're looking for. It is extremely dense and detailed. It will require a lot of work to get all the information that you need, but there are a lot of rewards there as well.

If you have not studied that Slav before, I would recommend:

http://www.amazon.com/Slav-Move-Everyman-Chess/dp/185744678X/ref=sr_1_2?s=books&ie=UTF8&qid=1347014456&sr=1-2&keywords=slav+defence

Slav: Move by Move by Lakdawala as it gives a great overview of the plans and ideas of the opening and provides puzzles and quizzes throughout the games to test your understanding.

The Slav is a great opening and I wish you luck in your studies!


How to calculate percentage of accuracy of game-play based on the number of mistakes, blunders and inaccuracies? For some time now, chess.com analysis suggests the accuracy of the gameplay based on the blunders, mistakes and inaccuracies, one committed during his/her gameplay. Now, my question is,
Whether there is any formula to calculate the accuracy of gameplay based on the inaccuracies, blunders and mistakes during the game? If not, then what are the other factors, that act on the accuracy?

The gameplay accuracy is a scale from 0 to 100 and it is calculated based on the accuracy of each of your moves. Chess.com collects a lot of data from played games that they use to evaluate which moves are more important for the final accuracy.
The final accuracy is a weighted average and that explains when you play a game with two book moves and a blunder why you can get an accuracy of 0.7 and not 66.7.
The average of a single move is determined by how close the evaluation deviates from the top engine suggestion and how far is the evaluation rank placed. If the move played was the 2nd best but was -3 instead of best -1, then that is more accurate than if the same move had 9th rank.
Chess.com has released these two articles that give some insight on the analysis:
How is it measured?
How to use game analysis?
Note:
Chess.com isn't open source and they haven't shared all the details of the calculation, so more explanation needs more speculation.


What is the best way to research openings and endgames in a browser? Basically, I just want to know if there’s any easy way to use websites to practice endgames and openings by just opening my browser. I keep finding downloads to Windows programs, which is a problem when I play chess on mobile devices. Then there are the options that require to pay, which isn’t really something I could do.

Three options I can think of immediately:
https://chess-endgame-trainer.firebaseapp.com/home is a fantastic chess endgame trainer.
Chessable also lets you create your own courses (for free) which you can then do spaced repetition on.
Listudy is another option.


Can white king capture defended pawn by pinned piece? Black can not move his bishop and can not attack the white king  even if the white king captured the black pawn.
Can the white king capture the pawn ?

No.

The king must not move to a square under attack by an enemy piece, no matter what, even if said attack is currently not allowed.

If the rule allowed exceptions like this, the logic would chase its own tail: If White is allowed to play Kxf4 - placing his king in danger of getting captured with the excuse that Black (supposedly) can't actually take it next move -, then by the same logic, Black should be allowed to play Bxf4, too - placing his king in danger of getting captured with the excuse that White cannot actually take it next move (because there is no next move as soon as White's king is captured)! But if Black is allowed to play Bxf4, then Kxf4 gets illegal again, because now the danger of recapture is real.

Thus, to avoid these headaches, White is not allowed to play Kxf4 in the first place.


How good can you get at bullet chess without playing standard? I hate standard chess. Sitting there on your ass for hours on end obsessing over every single little move... it's a nerd's game. It's often talked about as being a game of intelligence, but there's a reason why computers are so much better at chess than humans, while there's no robot out there creating breakthroughs in mathematics or science. Because it's not about intelligence, it's tedious calculation and nothing else. Ultimately, all it comes down to is doing the calculations and memorizing the lines. It's a game for computers, not for humans.

It is for this exact reason that so many games end in draws. Because there's a limit to the degree that we humans can calculate and memorize lines, hence the best players are often equally good at it, hence nobody is at an advantage, hence it's a draw.

But I'm fascinated by bullet chess, or as a maximum, 3 minute blitz. Now, this is a game for humans. It's not about how nerdy you are with your calculations, it's about something that is a bit more ... intangible. It's about instinct... intuition, ... a certain feel for the flow of the game. These are human notions that you can't program into a computer, and that's what makes it so fascinating to me. I mean, a computer can play bullet too, but importantly, the computer does not think of bullet like a human does. The human plays it differently. However, in standard chess, both the human and the computer are doing the same thing: endless calculations.

So with that in mind, my question is, how good can you get at bullet chess, without playing standard chess at all?

For what it's worth, I am ranked 2300 on lichess (bullet), 2000 (3-min blitz) and 1800 (10-min rapid).

I think that bullet is a skill that is half chess, but half is simply the ability to think and move quickly, which is the domain of young people. Yes, you can clearly get very good at it relative to your standard level of play. Your ratings seem to prove that.

I still question whether bullet is really good for your chess on a deeper level, but you do not seem to care about that, so if you are having fun, by all means, enjoy it. Nevertheless, this may still ultimately make you plateau permanently since bullet is very shallow in terms of depth of understanding. Plateaus vary from person to person, so just how good you can get will ultimately be something that you will have to just play and find out where you stand.

If you ultimately want to improve your depth of understanding, you do not have to choose between sitting there for hours, and bullet. You can play more using controls that are more of a happy medium.


What was the longest World Championship game? The recently concluded Game 7 of the 2014 Carlsen-Anand match went to move 122 before a draw was reached due to insufficient material. Is this the longest game played in a World Chess Championship match? If it is, what was the previous record holder? If it isn't, what games have gone longer?

Extra bonus points if you can also list the longest decisive game from a World Chess Championship match.

Clarification: By World Chess Championship I mean anything played for the FIDE or PCA titles, or the undisputed title if pre-FIDE.


How to train tactics methodically In sports, there are often times methodical ways to practice. In tennis, for example, you don't just play matches or just practice forehands, you practice hitting forehands cross-court deep into the corner target, then to the angled target, etc.
I'm wondering, what is the equivalent method of practicing tactics methodically in chess? Would it be to practice one motif repeatedly? Or is it to practice blitz+standard?

I'm wondering, what is the equivalent method of practicing tactics methodically in chess? Would it be to practice one motif repeatedly? Or is it to practice blitz+standard?

Neither.
In the chess world it seems to be to use some variation of "spaced repetition". There is a great answer by BlindKungFuMaster to a different question which says:

Spaced repetition is a learning technique that repeats content after increasing time spans according to learning success, i.e. faster for stuff you haven't grasped yet, longer if you do well.
In chess this is either used to learn a certain set of (easy) tactical exercises basically by heart ("woodpecker method" according to Axel Smith, Michael de la Maza, …), which is supposed to improve your tactical pattern recognition.

Since BlindKungFuMaster's excellent post Axel Smith and Hans Tikkanen have published a book expanding on the "woodpecker method" called "The Woodpecker Method" which includes some interesting history and background together with instructions and explanations of the method plus over 1100 graded exercise.
The main difference between spaced repetition and the woodpecker method is that Smith and Tikkanen emphasize increasing speed rather than time gap. Here are their instructions:

Step 1
Cycle 1: Solve as many exercises as you can manage in four weeks. These exercises are your set; and solving them brings you to the end of your first cycle. (The exact time period can be adjusted according to your lifestyle and circumstances, but try not to spend much more than four weeks. If you find yourself taking much longer than four weeks, you have probably either not been putting in sufficient time, or have included too many exercises in your set.)

Step 2
Take a break from chess for at least a clear day, and up to a week if you need it.
Step 3
Cycle 2: Solve the same set of exercises but faster: within two weeks is the target.
Step 4
Repeat steps 2 and 3, and repeat again. Aim to complete each cycle in half the number of days as the previous cycle (rounded up, when dealing with an odd number of days).
Step 5
The Woodpecker Method has been completed when the full set of exercises has been solved
entirely in one day – or after the 7th cycle, if you are unable to solve the full set in a day. In the final two cycles, you should focus more on spotting ideas, patterns and motifs at speed, and less on the finer details of calculation.

Interesting to note that Axel Smith credits the woodpecker method (named after the translation of Tikkanen's name into English) with his achievement of the GM title. This is what he says early in the book:

As mentioned above, I trained with the Woodpecker Method in the spring of 2010. That summer, I achieved three GM norms and surpassed the 2500 barrier, all within a seven-week period. The positive eﬀects did not stop there: the following year, my live rating brieﬂy peaked at 2601.
Such quick results from any type of chess training are rare in my experience, but for me the Woodpecker Method seemed to be just what the doctor ordered! The increased tactical acuity and consistency that came from working so hard with the method significantly decreased my blunders and made me more confident at the board.
Would I have made the same improvement with some other type of training? It’s not impossible – but my playing strength had not taken any significant leap in years, so I had been at a loss as to what to do diﬀerently to succeed. Although the Woodpecker Method probably wasn’t the only way for me to raise my play, it certainly proved to be a way. The intersection of my interest in the human mind and my motivation to stop blundering surely helped me to devote more time and eﬀort than I would have put into my usual training.


How to evaluate my move with UCI engine? I am looking for a way to analyse the moves I play. I'm NOT looking for a suggestion of a GUI that does this, or using Chessbase to do this. I want to know how to do this by communicating directly with the UCI engine.

For example, when I tell the engine:

position startpos moves e2e4 e7e5 d2d4  g7g6

go depth 30

it returns the best move in this position:

info nodes 11295495 score cp -40

bestmove f7f5 ponder g8f6

But what I want is the evaluation of my latest move g7g6. How do i get that?

Enable multipv on the engine. When you are at "e2e4 e7e5 d2d4" it will list all possible best moves that the engine considers in order of their evaluation. If you find "g7g6" in this list, then what you have considered is one of the best moves also considered by the engine and you'll obviously have the score associated with "g7g6". So, you will find this information before you make the move "g7g6".


What's the point of the Two Knights French? According to lichess, if Black simply goes 3...Nf6 against the Two Knights Variation, then the main line is 4.e5 Nfd7 5.d4. This is the exact same position as White would have reached if they'd played 1.e4 e6 2.d4 d5 3.Nc3 Nf6 4.e5 Nfd7 5.Nf3. Why play the Two Knights at all then if Black can just transpose into territory they're more familiar with? Is it just to avoid the Winawer?

Another idea of the two knights variation is to provoke 3...d4 and get some kind of reversed Old Indian. Some players like these pawn structures, and it also may not be blacks taste to be the one with the space advantage.
For example:
[FEN ""]
[Title "Analysis"]
[StartPly "99"]

1.e4 e6 2.Nf3 d5 3.Nc3 d4
    ( 3...Nf6 )
4.Ne2 c5 5.c3 $1 Nf6
    ( 5...d3 $6 6.Nf4 c4 $2 7.Qa4+ $18 )
6.cxd4 cxd4
    ( 6...Nxe4 $5 )
7.Ng3
    ( 7.e5 Nfd7 8.Nexd4 Nxe5 $10 )
7...a6 $1
    ( 7...Nc6 8.Bb5 $14 )
8.d3
    ( 8.Bc4 $6 b5 9.Bb3 $2 d3 $1 $17 )
8...Nc6 9.Be2 e5 $13

Objectively black is minimal better due to his space advantage, but white operates with the vacuum which d5-d4 has created in blacks position. He will sooner or later play f2-f4 and attack the pawn chain e5/d4, for example by playing h3 and Nh2. If black takes on f4 this will isolate the d4 pawn, and white may be able to win it. Of course that will not work if black plays it sensible, for example by protecting the pawn with Qb6 and Rd8. The stronger player will win.
But as you already said, Black can play 3...Nf6 and this transposes to the main lines.


Resources on the Bogo-Indian opening I'm looking for good resources to learning the Bogo-Indian opening:

 [FEN ""]
 1. d4 Nf6 2. c4 e6 3. Nf3 Bb4+.

For background purposes, I play at around the 1750 elo level. I like closed positions (I play the Caro-Kann & Slav defence as Black, & always open with 1. d4 as White). Lastly, I'm motivated to learn the Bogo-Indian because I'd like to avoid the Nimzo-Indian.

Thanks in advance!

One of my favorite chess you-tuber's - IM Christof Sielecki has written a book on it: Opening Repertoire: Nimzo and Bogo Indian http://www.amazon.com/dp/1781941092/

It would be worth to take a look at it!


Positionally Rich Opening Suggestions? I really want to play some positionally rich openings. Openings which require strategic planning and understanding, and not much direct attack and defence. I want the battle to be a "who can improve their position the fastest" sort of battle and not a "who can attack the quickest" sort of battle.
What openings would you suggest? (FYI, I'm 1700 rapid, 1700 blitz, rapid being what I take the most seriously)

d4 would be the best choice as white, for sure - generally leads to more positional situations.
Against the slav-
Exchange Slav is an option if you aren't annoyed by the drawish nature.
Against the QGD-
Exchange QGD (with a Nf3 0-0 setup like Karpov) is a good option.
You should probably avoid the Nimzo and Benoni (so, after d4 Nf6 c4 e6, play Nf3, and after d4 Nf6 c4 c5, play Nf3).
Thus, you'll have to learn the Queen's Indian, Bogo-Indian, and the line d4 Nf6 c4 c5 Nf3 (which transposes to a line of the Symmetrical English)- none will be too difficult to find something against that you like (main lines should suffice).
Against the Dutch, you can pretty much do the main line and it'll suit your wishes.
Now, as black- my recommendation would be the Caro-Kann, with a couple notes: 1) play 3...c5 against the Advance variation, as there are m any sharp lines if you play the main line Bf5. This appears to lose a pawn, but black has few issues getting it back.  2) It might be worthwile to play a sideline in the 3. Nc3 line such as 4...Nf6 or 4...Nd7 instead of 4...Bf5.
Versus d4, I would choose the Chebanenko slav (d4 d5 c4 c6 Nf3 Nf6 Nc3 a6) - a good video on it can be found here
This has the nice bonus of having a built-in rep vs c4, since you can just reply c6.
There are good courses on chessable for both of these defenses.
Personally, I've played almost all of this repertoire and have found it to be both good and positional.


At what level would a player be able to correctly analyze how ...a5 is superior to ...Bc5 if LiChess puzzle 94536 arose in a tournament? LiChess puzzle 94536 (from this game) begins with this position with black to play:

[fen "r1b2rk1/ppq1n1pp/3p4/3Ppp2/1bP5/3B1N2/1B1P1PPP/R2QR1K1 b - - 1 13"]

The fork 1...e4 is obvious, then white responds 2. Qb3 hitting black's b4 bishop.  We need to save the bishop, and my candidate moves were as follows:

2...Ba5 which I eliminated after some analysis, since it allows a removal of defender tactic with Rxa5 at some point.
2...Qb6 which I quickly eliminated since it pins the e pawn.
2...a5
2...Bc5

I couldn't distinguish between 2...a5 and 2...Bc5, and I fortunately played the correct move 2...a5 (which I thought was slightly better since it guards the c3 square, preventing white's battery).  The move 2...Bc5 is faulty because of the following:

   black's dark-squared bishop becomes trapped via the moves 3. Bf1 exf3 4. d4! Bb6 5. c5! and black cannot capture on c5 since 5..dxc5 e6+ drops black's queen.

After seeing the solution, I feel there is no chance of me recognizing this in an actual game---I'd probably declare there to be virtually no distinction, and play a move to avoid wasting time.  Maybe someone at a higher level than me might find it in a tournament game.

Question: At what level would a player be able to correctly analyze how ...a5 is superior to ...Bc5 if this puzzle arose in a tournament?

I'm trying to improve, and get an idea for how my improvement is going.

Some things make it difficult....

several motifs are involved: two clearances, trapped piece, discovered attack (and you have to see all them in order to understand the problem)
the particular form of these motifs is non-standard (meaning there are  more usual patterns for any of these motifs):

moving the bishop to f1 to clear the d pawn, is rare;
trapping the bishop with just one pawn (more common is a theme with a white pawn on b4 and a black pawn on c7);
clearing the diagonal by playing c5 (this is essential for the discovered check);
discovered check with a pawn is not very common either

Moving one of the double-attacked pieces is not what one might come up first, because it often loses a tempo. One might be tempted to have an attitude like: anyway I'll lose one of the two pieces, perhaps I could  make a useful move with one of the other pieces.
One would have to calculate this defensive tactics from the black, i.e. from the attacker side which is for many people more tricky as (at least lower rated) players tend to do a lot more tactics that ask for winning/mating, etc than doing defensive themes.
In a tournament game (unlike in a composed study) you never know whether there is one good move or several equal (or almost equal) moves.

Some things in favour of finding the correct move:

Since e4 has the potential to win a piece and therefore the game, the black player in a tournament game would want to make extra sure and invest plenty of time to check any defensive options.
The move a5 once and for all makes sure that the bishop on b4 is save, because it cannot be attacked by white pawns on that square and at most one would lose a pawn on any trade on b4 (after having checked that the pin along the a-file is not a problem).

Overall I think that because of the multiple non-standard motifs involved it is a very difficult problem in a tournament game. If you want a number, my estimate would be around 2200 ELO, but this might be more about how careful the player is than about what his rating is.

Given enough time (10+ min or so), I believe that a lower rated player of around 1800 should be able to find the solution if told that there is a unique solution.


Najdorf poisoned pawn with or without 7..h6 8 Bh4 In the Sicilian Najdorf poisoned pawn variation what is the difference between including the moves 7...h6 8 Bh4 (as many top players do) and not including them?

[FEN ""]
1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6. Bg5 e6 7. f4 Qb6 (7...h6 8. Bh4 Qb6 9. Qd2 Qxb2) 8. Qd2 Qxb2

One reason is that it avoids a certain line that you would get after playing 7...Qb6, which is 8.Nb3

If Black plays 7...h6 first, 8.Bh4 Qb6 9.Nb3 is no longer possible because Black can play 9...Qe3+ winning the f4-pawn. This would not have been the case in the  7...Qb6 line since the bishop would have still been on g5, protecting the pawn.

Another reason is that sometimes Black would like to play ...g5.

[FEN ""]
1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6. Bg5 e6 7. f4 Qb6 (7...h6 8. Bh4 Qb6 9. Nb3 Qe3+ 10.Qe2 (10.Be2 Nxe4) 10...Qxf4) 8. Nb3 Be7 (8...Qe3+ 9.Qe2)


What would happen if a game lasted for more than 24 hours? Technically it is possible for a game to last more than 24 hours, since after 40 or 60 moves each player generally gets a 30-second increment.

In an endgame, the player with the advantage will just need to be careful of the fifty-move rule and the threefold repetition rule, and he would be able to keep pressing for many many hours hoping that his opponent will crack and make a mistake.

But the problem is: 24 hours after the game has started, the next round would need to start!

So what would happen?

Would the entire round be delayed for everyone participating in the event?
Would the next round start normally on time for everyone, except for 4 players (including the 2 players playing the problematic game) who would need to wait for the problematic game to end?
Would the next round start normally on time for everyone, and the two players who are still playing the problematic game would need to play their next round games while simultaneously continuing the problematic game?
Would the arbiters simply decide to end the problematic game, considering it as a draw?
Would the FIDE President need to add a new rule to prevent this kind of situation from happening again?

Although replies by Brian Towers and StudentT are the right ones (both players would be disqualified) from a theoretical points of view it would be possible that a game has not ended in time for the next round to begin. I would even say that it's possible that it could actually happen in a tournament with 3 rounds per day.

I case it would happen I guess the game would be adjourned by the arbiters. The entire round would not be delayed/cancelled, but the result would be considered to be a draw for pairing purposes only. See General handling rules for Swiss Tournaments, point D.1, and Laws of Chess, point E.1.a.

From Laws of Chess

  If a game is not finished at the end of the time prescribed for play,
  the arbiter shall require the player having the move to ‘seal’ that
  move. The player must write his move in unambiguous notation on his
  scoresheet, put his scoresheet and that of his opponent in an
  envelope, seal the envelope and only then stop the chess clock. Until
  he has stopped the chess clock the player retains the right to change
  his sealed move. If, after being told by the arbiter to seal his move,
  the player makes a move on the chessboard he must write that same move
  on his scoresheet as his sealed move.

from General handling rules for Swiss Tournaments

  Adjourned games are considered draws for pairing purposes only.

Update: I've found a real example in a Catalan tournament (Masdenverge). You can read tournament rules here: http://www.escacsmasdenverge.com/. It was an U-2200 tournament (to allow a 60+30 time control) and three rounds per day were scheduled. See the note where this possible problem is mentioned:

  NOTA: Si una partida s'allargara en excés, superant l'hora prevista
  per a l'inici de la següent ronda, l'àrbitre principal podrà segons el
  seu criteri, emparellar amb el resultat provisional de taules, a
  l'efecte de que els altres participants puguen jugar la ronda següent.
  Quedaran ajornades les partides dels jugadors que estiguen jugant la
  ronda anterior i una vegada finalitzada, s'unixen a la ronda.

A free English translation:

  If a game lasts for too long, exceeding the scheduled time for the
  start of the next round, the main arbiter may at his discretion,
  proceed to the pairing with the interim result of a draw, to the
  effect that the other players can play the next round. Games of the
  player who are still playing the previous round will be delayed and
  once these games end they'll join the current round.

As you can see in this case the draw for pairing purposes rule is used, but games are not adjourned but the players will continue to the end, and then they'll join the next round.


When playing chess online, what does 1-1 mean? When playing chess online, when your opponent says 1-1, what does 1-1 mean?

As your question isn't very clear, but by what you have mentioned about your opponent saying 1-1, i can say there are 2 possibilities.

He either means it as the score between you 2 such as, you guys have played 2 games and both ended in draw, considering half point to each player per draw, it's 1-1, or both player has lost 1 and won another so 1-1 again.

Or he might be saying it regarding time control of a game. 1-1 meaning 1 minute per player and 1 second increment per move for the whole game.

More examples for time controls are such as : 2-1, 5-2, 10-0, 15-10, etc. Where the first number indicates the time in minutes per player for the whole game and the second digit indicates the increment time in seconds per move per player till the end of the game.


What should I do when my opponent and I are "chasing" each other around? I think this is a very noob mistake, but bear with me.

Sometimes I run into a situation where my opponent and I "chase" each other around, repeatedly checking the king and escaping the check by moving the king.

Let's say I'm the one getting checked. My opponent checks me, I then move my king to escape the check, my opponent checks me again, I move my king, etc.

The only way to get out of this repetitive cycle is for my opponent to choose not to check my king, but that's probably not going to happen.

What should I do in such a situation?

What should I do in such a situation?

Shake hands and agree a draw.

If it is a serious game where you are writing down the moves and your opponent doesn't agree to a draw then mark the move on your scoresheet where the last time a pawn was moved or a capture was made, mark the move 50 moves on from that and when you reach that move make a draw claim under the "50 move rule".


Losers Chess variant engine Is there a strong Losers chess variant engine?

I had a look at stockfish, but it doesn't support Losers chess, seemingly.

(to be used on a Linux platform)

https://github.com/ddugovic/Stockfish

has what you want. Not an offical version, but should be stable for production.


In a tournament game, what should a player do if he find that his opponent's position is impossible, which was caused by an earlier illegal move? For example, if a player realises that his opponent has two bishops of the same colour after a certain legal move (and assuming that it is clearly not caused by any pawn promotion), which implies that his opponent has made at least one illegal move earlier (but it was recognised until much later in the game), what should this player do?

If there is a record, can he trace back the illegal move and declare that he wins the game because an illegal move was made earlier?
Even without a record, can he still win the game because he can theoretically prove the existence of at least one illegal move made by his opponent?
Or should the game continue as it is now, even though the position is impossible?

Section 7.5.1 of the FIDE Laws of Chess has the answer:

  7.5.1 An illegal move is completed once the player has pressed his clock. If during a game it is found that an illegal move has been completed, the position immediately before the irregularity shall be reinstated. If the position immediately before the irregularity cannot be determined, the game shall continue from the last identifiable position prior to the irregularity. Articles 4.3 and 4.7 apply to the move replacing the illegal move. The game shall then continue from this reinstated position.

The player found guilty is not penalised for the illegal move, provided their opponent has intended to play a move:

  4.7.1 A player forfeits his right to claim against his opponent’s violation of Articles 4.1 – 4.7 once the player touches a piece with the intention of moving or capturing it.


Tit for tat sacrifice I have noted in a number of games from Master players that sacrifices are rapidly played till both sides are reduced to just about equal in material and virtually the same pieces, at least in value.  Is this a deliberate act by both players?  It seems to be strategical by clearing the board of the garbage and getting to the heart of the matter, victory.

I have noted in a number of games from Master players that sacrifices are rapidly played till both sides are reduced to just about equal in material and virtually the same pieces, at least in value.

I don't think that happens often at all. What does happen is that players exchange pieces -- say white captures a piece, in return black takes a piece back, often the piece that just captured. That is perfectly normal, but it's not a sacrifice. A sacrifice is when you let something of yourself be captured and then you don't capture anything back.

It's natural for a game between two strong players to end up with more or less the same material; they're good enough to avoid moves that simply lose material outright.

  Is this a deliberate act by both players?

Well, they would of course rather just capture pieces without having their own pieces captured in return, but the opponent doesn't want to go along with that.

It's normal to react to a piece that is threatened by defending it -- so that the capturing piece can be captured back.

Generally every move a master makes is a deliberate act, or they wouldn't be any good at the game. A decision to exchange a set of pieces is not to be taken lightly, apparently the master decided it was the best move to make in the given position.

  It seems to be strategical by clearing the board of the garbage and getting to the heart of the matter, victory.

I don't know what this means.


Why does the engine dislike white in this position despite the material advantage of a pawn and other positional factors? After a trade that sacrified a bishop and a knight for two pawns and a rook, the game reached the following position: (White to move.)
[FEN "2r2qk1/1b1n1pb1/p4n1p/1p4p1/4P3/1BN2P2/PPP3PP/R2Q1RK1 w - - 0 17"]

At this point the engine was evaluating the position as -1.65.
I am confused with this evaluation. After this trade, white can go Qe2 and soon take claim of the open file with a rook and it seems that all white's pieces are with good activity and the pawn structure seems better than black's, so at first glance it seems to me that not only there is material advantage (white's up a pawn) but also a positional one.
I tried looking at the engine's suggested moves to see what I was missing and the moves are obscure to me. For instance, after 1.Qe2, the engine suggests 1...Bc6 and after 2.Rfd1 it suggests 2...Nh5. Both these moves don't seem to accomplish much to me. I can see a threat of jumping the knight to f4 eventually but it does not seem so dangerous. What makes some sense to me is that the bishop in g7 will probably be able to disrupt the pawns on the queenside either by doubling the pawns on the c-file by taking the knight or by taking on b2 if white has to move the knight due to b4 or some other threat. In any case, this should take some commitment and due to white's pieces' activity it seems that this might not be easy to go unpunished or simply stopped. Furthermore, this would justify to me perhaps an evaluation closer to 0, not -1.65.
Maybe worth noticing that the engine suggests 1.Qd2 instead of 1.Qe2, but analyzing this branch wasn't very fruitful either. For instance, one variation is as follows:
[FEN "2r2qk1/1b1n1pb1/p4n1p/1p4p1/4P3/1BN2P2/PPP3PP/R2Q1RK1 w - - 0 17"]

1.Qd2 a5 2.a3 a4 3.Ba2 Ne5 4.Rad1

At this point, the evaluation is at -0.83 and I don't see a clear problem either.
This is why I'd appreciate if someone can explain why the engine likes black in the first highlighted position so much.

Interestingly, even without looking ahead and just evaluating the immediate position, Stockfish thinks Black is ahead by nearly half a pawn despite agreeing that White is ahead in raw material. Looking at the sub-scores, the "Imbalance" category is where most of Black's score is coming from.
"Imbalance" looks at which pieces are on the board and makes assumptions about how well they coordinate together. For example, each rook gets a bonus for each friendly knight and bishop but a penalty for other friendly pieces, and a penalty for enemy bishops and queens but a bonus for enemy knights and pawns.
In this position, Black is getting a bonus for having the bishop pair. White seems to be getting a penalty for having two rooks and a queen (the algorithm apparently thinks rooks don't work well with friendly rooks or queens) while Black's queen gets a bonus because the extra enemy rook and pawns are considered as potential targets just for existing. Overall the synergies between the various pieces actually give Black more of a score boost than the bishop pair itself does, and in total it's enough for Stockfish to think it outweighs the material deficit.


48 pieces on one board I saw this picture on the Internet.

I am wondering if there is any way to play on this board. Does anyone know what the rules are for this type of chess?

It is one of many forms of three-player chess, apparently called 3 Man Chess. Rules are explained here.


How can I compare top chess players that were not scored using Elo? Given that Elo ratings appear to only have been around officially since 1970, how do you compare top chess players that were not scored using Elo (e.g. their careers came before ratings existed)?

Jeff Sonas at chessmetrics calculated ratings for players going way back, using the games we have available.  Gives a pretty good picture of players relative strength.

Note this is up to around 2005, so you won't see players like Carlsen on there.


Notable decisive grandmaster-level games where only pawns were captured? Are there any notable Grandmaster-level games that were won with only pawns captured, but no higher level pieces?

Last week GM Nigel Short tweeted:

  Not sure I have won too many games without a single piece or pawn being captured. Short-Derakshani, Beautiful Minds Krulich Cup, rd 10.

I can't find PGN of that game yet and am at work, but you can replay it at https://chess24.com/en/watch/live-tournaments/krulich-cup-2016/10/1/1 - all 32 pieces still on the board, until at move 20 black removed the last escape square of his own queen. After 21.Ng2 attacking it, black resigned.

Moves, taken from here:

[FEN ""]
1. c4 e5 2. e3 Nc6 3. a3 Nf6 4. Nc3 g6 5. d3 Bg7 6. g4 h6 7. Bg2 d6 8. h3 Be6 9. Nd5 Qd7 10. Ne2 Nd8 11. b3 Nh7 12. e4 c6 13. Ne3 Qe7 14. Bb2 Bd7 15. d4 O-O 16. d5 c5 17. Qc2 Qh4 18. Nc3 b6 19. O-O-O Nb7 20. Bf1 Ng5 21. Ng2 1-0


Stockfish: What is the maximum (minimum) centipawn score that a position might be evaluated at? With the exception of checkmate and mate-in-x positions, what is the highest centipawn score that a chess position might obtain upon Stockfish evaluation?

This is a practical question because there are situations where one would want to normalize position scores to [-1, 1]. As a starting point I wrote a small script that evaluates the positions (depth=10) found in 100 PGNs and found the highest score to be 3396. Is there an upper bound (or lower bound for negative scores)? Does the evaluation depth effect the bound?

EDIT: I've selected the answer provided by Chromatix because it solves the problem that motivated my question. For those who are curious about the actual bounds, it's worth noting that looking at approx. 400k positions from grandmaster games I found that the highest and lowest centipawn scores were 7881 and -7658, again, using Stockfish (depth=10).

The best way to normalise a centipawn score to [-1,+1] range is using a sigmoid function, as that closely approximates the likelihood of a given centipawn advantage converting to a win, and avoids the need to identify a strict maximum or minimum.  This is discussed here.


King facing king on same line or column Just returned to chess after 40 years (yes I know).  I have a memory of being taught that the kings could not face each other on the same line or column. Chess Titans computer game doesn't seem to recognise this or have I got it wrong.  I understand the rule of Kings not being next to each other but I'm talking about the along a whole column for example


Taking notes of time usage during game While I know taking making any notes during a game is against the rules (and Wesley So was disqualified for this), does this include denoting the time usage after each move?

FIDE rules allow you to record the time:

  8.1.4     The scoresheet shall be used only for recording the moves, the times of the clocks, offers of a draw, matters relating to a claim and
  other relevant data.

https://www.fide.com/fide/handbook.html?id=208&view=article

USCF rules also allow you to record the time:

  20C. Use of notes prohibited. The use of notes made during the game as
  an aid to memory is forbidden, aside from the actual recording of the
  moves, draw offers, and clock times, and the header information
  normally found on a scoresheet.

U.S. Chess Federation. United States Chess Federation's Official Rules of Chess, Sixth Edition (Kindle Locations 1925-1927). Diversified Publishing. Kindle Edition.


Smartphone app with Wordfeud-like time constraints In Wordfeud, it's kind of play-and-forget. When your opponent makes a move, you get a notification. Typically I would move once a day while commuting to and from work. A game would typically take a week to finish.

I'm used to playing chess on the eboard FICS client.

However, I haven't found a way to utilise the FICS network to play in this more casual way. It seems that if you disconnect, you defeat. Even if you didn't, you wouldn't get any notifications. I've played on a few websites, where you get an email, but it doesn't really exploit the bells-and-whistles of the smartphone.

So, could you recommend me a client that would do the above?

A smartphone friendly (responsive) website with email notifications is also interesting as a second option.

You're looking for something called Correspondence Chess where you can make moves at your leisure in a time frame you're comfortable with. Chess.com and Chess Time both provide smartphone apps with this capability. Chess.com has many more features and Chess Time only provides correspondence.

iOS and Android for Chess.com
iOS and Android for Chess Time


Should you always try your best (play as if your opponent is a grandmaster)? Should you always play with your "best" skills no matter how (un)skilled your opponent is?

Is there a situation where intentionally not playing to the best of your abilities is a good strategy? Like, let's say you're playing against a chess noob. You don't need to waste moves defending your army because your opponent probably won't even notice the hanging pieces. You can checkmate your opponent faster by doing things that are usually considered bad strategies, such as moving your queen out too early in the game.

Additionally, I saw in the Chess.com mobile app that its "best move" hints change relative to the computer opponent's level. Seems like you should play against newbies differently than how you play against grandmasters.

Is purposely "not trying your best" sometimes advantageous?

Is it a good strategy to always play like a grandmaster?

Obviously yes, but unfortunately 99% of chess players are unable to do this even if they wanted to. ;)

Is it a good strategy to knowingly play moves that you know (or strongly suspect) to be mistakes?

No.

"Mistake" in the sense that there is an answer that screws you if your opponent finds it.
Because either they find it (short term downside) or it works out and you just reinforced a flawed pattern in your brain (long term downside). Blundering your pieces left and right is not a sound strategy, not even against "noobs" (after all, you still need to have some material left to actually mate).

Is it a good strategy to knowingly play moves that you know (or strongly suspect) to not be best (but still okay)?

Sometimes.

In many situations, there are multiple candidate moves and it may have some benefit to play the move you judge second or third instead of the "best" one.

Sometimes it's better to settle for a small but safe strategical advantage (that you are confident to transform into a win against a "noob" anyways) instead of a potentially big advantage that needs a lot of precise tactical play to hold (with the additional risk that you miscalculated somewhere).

Keeping the game less complicated when ahead gives the better player some meta advantage (he's less likely to blunder, and as long as he doesn't, he will eventually win), which might make an otherwise suboptimal move the most advantageous.

Or vice versa, sometimes it may be worth it to go for a move that gives your opponent some advantage in one aspect of the game, while you only get a smaller one in some other aspect. Most gambits come to mind, for example. What matters is that you still should not play clear mistakes, only slightly "worse" moves where you do get some compensation. Sacrificing a pawn for initiative that's probably worth less than a pawn, or even sacrificing a piece for a mate attack is fine. Sacrificing initiative by moving out the queen too early for some hit-or-miss chance to apply the Scholar's mate is not a good strategy, because if they find a good answer, you end up with no compensation at all; and if they don't, they are so inexperienced that any healthy opening would probably have won easily (and quickly!) as well without using a strategy that is useless against better players (again: either short or long term disadvantage).

Making the game more complicated when things are even gives the better player some meta advantage (he's more likely to find a better way through the jungle), which might make an otherwise suboptimal move the most advantageous.

However, these kinds of strategies are used by grandmasters as well, so ironically you are still playing like them.

Is it a good strategy to knowingly play moves that you are not sure about (they may be good, they may be bad)?

No.

Often, this cannot be avoided, of course (your skill sets limits to calculation depth and positional judgment). Thus everyone has to do it to some degree. It's not a "good" strategy though. Ideally you should always try your best to evaluate a given position.


Would the Elo rating system remain useful if different tournament formats were used? More or less what is asked in the title. I am familiar with how the system itself works, but I am wondering if there would be any issues if most chess tournaments didn't follow the Swiss format and to a lesser extent, round-robin and match formats which all have each player play a similar number of games. However, consider a single-or double-elimination tournament bracket, which would mean that when a system was first implemented, stronger players would be playing more games in those tournaments than the weaker players who would be eliminated sooner.

Also the question is not limited to issues in relation to the accuracy of the ratings in a statistical sense, though that would of course be the main consideration.

Theoretically there's no problem. But, for example, if 'parking the bus' approach (a player gets a high level in ranking, then he stops playing) is one of the most known practical issues of Elo ranking, the problem should be with weaker players that play just brackets, with one or few games every tournament.

Many post-Elo ranking systems, as Glicko (for chess), or TrueSkill (for X-box games), or rankade (our multipurpose ranking system) have some 'activity dynamics feature' to avoid this.

Rankade adds the option for different weights for match, due to different tournament format and/or match duration, and more.

While playing one-on-one (as in a chess group) or in symmetrical factions (as in basketball group), the total number of rating points is conserved. as per Dag Oskar Madsen comment.


Looking for books on the Benoni I am looking for books in the Benoni where this sequence of moves is played, so:

 [fen ""]

1.d4 Nf6 2.c4 c5 3.d5 e6 4. Nc3 exd5 5. cxd5 d6

And black's plan after that is g6.

Also if possible that it can be electronically downloaded/bought.

Depending on what you are looking for, there are a few interesting books. If you are looking for a book to start to learn the opening, I suggest you take a look at:

Starting out: Modern Benoni by Endre Dr. Vegh.

In such case, you may also want to round up your repertoire with the companion book:

Starting out: Benoni Systems by Alex Raetsky.

Which provides a more complete coverage of some similar lines (but not exactly the same, although some intersection is inevitable) that are not exactly achieved through the main move order.

If you already know how to play or what you want to play and are looking only for ideas, then the Dangerous Weapons book is definitely what you may want to check:

Dangerous Weapons: The Benoni and Benko by several authors.

Last but not least, if you are already a well versed player on the Modern Benoni and just want to keep up with some theoretical developments in the last years, and what trends are being followed, I strongly suggest the book:

Chess Developments: The Modern Benoni by Richard Pallister.

My experience with the Chess Development series arises from the Dragon and Grunfeld books, which definitely are worth the money if that is what you are looking for.

I obviously have not fully read them all. I have read a couple of chapters of the first three books, and the last one comes from my experience with the series as a whole.


Puzzle - Mate in 5 - #001 I've been writing some chess puzzles lately and I thought I would post some of them up here. I'm quite fond of this one so I thought I would share. I traditionally am not a fan of problems that are a "Mate in X," especially when it's in five, but the position, I think, is aesthetically pleasing. The real problem isn't the mate, in my opinion, it's setting it up.
[Event "Forced Mate in 5"]
[Date "2020.11.05"]
[White "White"]
[Black "Black"]
[WhiteElo "2622"]
[BlackElo "2622"]
[Annotator "Bateman, David"]
[FEN "2r1qbnr/1b4p1/p2pNk1p/npp1pP2/4P1Q1/2PPB3/PP4PP/RN3RK1 b - - 0 1"]
[SourceVersionDate "2020.11.19"]

1... Bc6

White to move and force mate in 5 moves.
I'm inspired by a number of games, but primarily Alekhine vs Janoski, 1924 New York.
Note: Only recently have I learned that problems and puzzles are accepted here and I believe it to be a better community for them.

Nice mate!
[Event "Forced Mate in 5"]
[Date "2020.11.05"]
[White "White"]
[Black "Black"]
[WhiteElo "2622"]
[BlackElo "2622"]
[Annotator "Bateman, David"]
[FEN "2r1qbnr/1b4p1/p2pNk1p/npp1pP2/4P1Q1/2PPB3/PP4PP/RN3RK1 b - - 0 1"]
[SourceVersionDate "2020.11.19"]

  1... Bc6 2. Bg5+ hxg5 3. Qxg5+ Kf7 4. Nd8+! Qxd8 5. Qg6+ Ke7 6. Qe6#

  The mate is identical if 4... Rxd8 is played instead. The key idea is to force a piece onto the d8 square in order to cover the two squares the queen on e6 cannot cover - f8 and d8.


How many pawns make up for a missing queen in the endgame? My partner and I are newbies, and recently found ourselves in this position:
[FEN "8/8/8/6kp/p5p/8/K/6Q w - - 0 1"]

I expected white would easily win because of the queen (and point) imbalance, but white never made time to free the king for the fight on the other side of the board, and there doesn't seem to be any way for the queen to handle that pawn-king cluster by herself.
My question: how many pawns generally make up for a missing queen in the endgame?  According to the point system, black would need nine pawns, but that seems like too many to handle.  Or would a more skilled white player have no problem dispatching pawns at this stage?

The simple and obvious answer is that it all depends on the position of black's pawns and king. In general the further up the board the pawns the better for black provided the king is in contact with the pawns, preferably in front of them.
Worth pointing out that the position you give is winning for white because the pawns aren't far enough forward. From what I said earlier it will be clear that white's first task is to separate black from the pawns, then win them.
This is how it is done.
[fen "8/8/8/6kp/p5p/8/K/6Q w - - 0 1"]

1. Qh2 {Cunningly not allowing the king to come forward} h4 2. Qe5+ Kg6 {Step 1 quickly accomplished. Black king separated from the pawns} 3. Qf4 Kh5 4. Qf5+ Kh6 5. Qxg4

and it is game over.
Move the kingside 2 rows forward, however, and best play is a draw, although white can give black opportunities to go wrong. At the same time white has to make sure black can't promote a pawn by checking, pinning or threatening mate.
[fen "8/8/8/8/p7/6kp/K5p/6Q w - - 0 1"]

1. Qe3+ Kh2 {only move} (1...Kh4?? 2. Qf2+ Kg4 3. Ka3  Kg5 4. Qg3+ Kf6 {anything else and Qxh3 will be check} 5. Kxa4 {and the king is going to come over and take the pawns}) 2. Qf4+ Kh1 {another only move} (2...Kg1?? 3. Qg3 Kf1 (3...h2 4. Qe1#) 4. Qxh3 Kf2 5. Qh4+ Kf1 6. Qf4+ Ke1 7. Qg3+ Kf1 8. Qf3+ Kg1 9. Ka3 Kh2 10. Qf4+ Kh1 11. Qh4+ Kg1 12. Kxa4 Kf1 13. Qf4+ {and repeating the process is going to bring the white king over to help and deliver mate}) 3. Qf3 Kh2 4. Qf4+

The two keys to playing these kinds of position are calculation and endgame knowledge. For instance in the second position it is key for black to stop white from winning the h pawn. That is because with just the g pawn black is lost. However replace the g pawn with either an h pawn or an f pawn and the position changes back into a draw.


French Defense Exchange variation - Qh5? [fen ""]

1. e4 e6 2. d4 d5 3. exd5 exd5 4. Bd3 Bd6 5. Nc3 Ne7 6. Qh5

I played this as white, and my last move seem to bother my opponent a lot. So I'd like to know if 5. ... Ne7 is correct and if my early queen trip is justified. If this is the case, which attacking ideas does white have. I later put my bishop on g5 (which is pretty obvious), but after this I had the feeling that I could do more to keep the pressure.

6.Qh5 is not so great because Black has 6...Nbc6, both attacking d4 and threatening ...Nb4 trading off White's important light-squared bishop (it can't move to e2 or something because of ...Nxc2+). White seems to be better off preemptively defending the d-pawn with a move like 6.Nf3 or 6.Nge2.


Programmatic method to determine if a move is passive or aggressive I'm currently trying to determine if a player on average plays more aggressive or defensive games. To do this I wanted to look at a game from that player, then average the amount of aggressive moves vs defensive moves. But the real issue is identifying if a move is aggressive or defensive.

I am looking for a method to determine if it's aggressive or defensive using a Machine learning/AI type algorithm, rather then having a bunch of if-else statements. I've seen this other question regarding this topic. In an answer to that question, user @HelloWorld recommended to use something called the "Monte-carlo tree search". I've done some basic research of the search, and I don't understand what they mean by "margin error". Can someone explain what that means and how it ties to this topic?

Also if you have any other algorithms to determine if a move is passive or aggressive, I'd love to hear it.

As described here the min-max algorithm is used in order to get the best strategy from any position in games, and therefore in chess. It uses tree ordering of the moves and each layer in the tree describes another player's move. The leaves at the bottom of the tree are the "values" gained from reaching this position with the sequence of moves from going down the tree. The algorithm assumes that the other player is playing his best possible moves also.
This algorithm was used for example in Deep Blue, but the problems were that the branching factor of each node in the tree gets huge after couple of moves. So this is very hard to calculate.

In the matter of your question, I don't think you could gain any knowledge about passive/agressive moves from min-max algorithm, as it only tells you the best moves (not knowing if it was passive or agressive).
I think a better approach to determine wether a move is agressive or passive will be tagging a large amount of moves in different positions in the game (with tags being 'passive'/'agressive') and training a Neural Network to determine if a new move that it never saw is passive or agressive.