How can I programmatically detect kings side / queen side pawn storm I read from wikipedia that:

  A pawn storm is a chess strategy in which several pawns are moved in
  rapid succession toward the opponent's defenses. A pawn storm usually
  involves adjacent pawns on one side of the board—the queenside (a, b,
  and c files) or the kingside (f, g, and h files).

But it does give an exact definition. Is there a precise definition of king-side/queen-side pawn storm, that I can use to programmatically detect this theme?

I doubt there is any generally accepted definition for a pawn storm. Chess is not a science after all. Anyway, it should be possible to write a program detecting most pawn storms with only few false positives. Because of the lack of any clear definition, other chess players will be more or less satisfied with your results.

So here is my approach. Obviously this is quite subjective – it highly depends on my view of pawn storms.

At first you have to rule out endgames. In a King and Pawn endgame I would not call rapid pawn movements a pawn storm. There is also no clear definition when an endgame starts, but the number of pieces (and their value) one the board could give a clue.
In my experience the phrase "pawn storm" is mostly used for a pawn storm towards the king. I would not call a minority attack a pawn storm. So if the king is on the f,g or h files, the pawn storm should occur on these files as well (which can be easily checked by your program.) If you want to include minority attacks, just ignore this point.
For the actual pawn storm I‘d just use a simple numeric value, eg. "two pawns on adjacent flank files have reached the fifth rank".
As "rapid" is in Wikpedia‘s explanation: Again, use some numeric value such as "For a certain amount of moves at least all three moves a pawn on that flank is moved."


In an opening tree on ChessBase, how can we fix the statistics so that transpositions are not taken into account in the total number of games? In an opening tree (also called "opening explorer" or "openings book") on ChessBase 12, here are the statistics that we get after 1. Nf3 c5 :

So it seems that after 1. Nf3 c5 White will play 2. e4 93% of the time.
It is obvious that these statistics are nonsense.
Everyone knows that after 1. Nf3 c5 White will play 2. c4 50% of the time, 2. g3 30% of the time, and 2. e4 only 10% of the time.
White players who play 1. Nf3 are generally not very interested to get into an Open Sicilian...
"2. e4 464238" does not mean "in this position White has played the move 2. e4 464238 times", it just means "the position reached after the move 2. e4 has been reached 464238 times by different move orders".
How can we resolve this problem?
It should not be physically impossible, since most other opening trees do not have this issue (ChessOK's opening tree, 365Chess' opening explorer and FICS' opening explorer do not have this problem).

When we do a right click, and then click on "Properties", this window pops up:

But unfortunately checking or unchecking the box "Unplayed transpositions" does not seem to do anything.

Unfortunately, many of the statistical functions of the Opening Book feature in ChessBase have been unreliable in every version I've owned.

For example, after the Caro-Kann line 1. e4 c6 2. d4 d5 3. e5 Bf5 4. Nf3 e6 5. Be2 Nd7 6. O-O h6 7. Nbd2 Ne7 8. Nb3 Qc7 9. Bd2, the opening book PowerBook 2013 shows this table:

Move       N     %    Av  Perf
          15  76.7  2409  2283

9...Bh7    8  56.3  2433  2494
9...g5     6  83.3  2405  2233
9...Nc8    4  62.5  2393  2335
9...a5     2  50.0  2561  2564
9...Be4    1 100.0  2414  2315

Well, first off, you'll notice that the number of games in the total (15) has no relation to the number of games in each variation given (a total of 21).

Second, if you do some simple arithmetic, you can work out that the average White win percentage is actually 66.7%, not 76.7%, as reported.

Well, then, let's ignore the overall position total statistics, and move on to examining a line item. Let's look at the 9...Bh7 line, which this table says was derived from 8 games, with a White winning percentage of 56.3%

If you make that move, you get a new table. Since we're now at the new position, the position statistics at the top of the new table should read the same as those from the 9...Bh7 detail line of the parent table from the prior position, right?

Here's what they actually say:

Move       N     %    Av  Perf
           8  56.3  2545  2484

Not bad, right? The first two stats agree... but the Average ELO and Performance ELO numbers are off by 100 ELO in the 1st stat, and 10 ELO in the 2nd.

And here's the full table for the new position

Move       N     %    Av  Perf
           8  56.3  2545  2484

10.a4      4  75.0  2455  2513
10.Bb4     4  62.5  2557  2537
10.Rc1     2  50.0  2650  2591

Again, the total # of games is unrelated to the # of games in each of the continuations.  And this time, the White winning percentage works out to 65%, not 56.3%.  And the position's Performance ELO is clearly not the average of the continuations' Performance ELO. It should be 2538, an error of 50 ELO.

I picked a ready example from a game I was looking at a few minutes ago, but any game will do to demonstrate this problem.  I frequently find that when I try to choose a move from an apparently winning continuation that the the detail data from the resulting position just doesn't support the apparently "winning" statistic. In some cases, it could say White has as much as a 60% winning percentage for the continuation, and then in the next position none of the further continuations has a percentage higher than 50%. Simply put, it's nonsensical.

Now, here's where it gets interesting:
I have set my Reference Database as the database of games that was supplied with PowerBook 2013 (PowerGames 2013). PowerBook 2013 was generated by ChessBase using all of the games from PowerGames 2013, and only those games.

I can now open the Reference window pane, and it will look up the statistics from the games in that database. They should be identical to the stats shown in the Opening Book pane, but they're not.

In fact, the Reference statistics for the 2nd position (after 9...Bh7) show the following:

10.Bb4     4  62.5
10.a4      2  50.0
10.Rc1     2  50.0

This is where the total statistics in PowerBook 2013 are coming from! The total number of games = 8 (correct), and the average performance = 56.25% (correct)!

In fact, in the PowerBook 2013 continuation stats there appear to be 2 extra games where 10.a4 was played (and which White apparently won), but they don't appear in the Reference database stats at all, and they aren't factored into the PowerBook 2013 totals stats.

It doesn't really matter whether this is a problem inherent in the commercially-sold books from ChessBase, or in how the ChessBase database software uses/calculates/displays the statistics. Simply put, there's a defect here that's been present since at least ChessBase 6.0, and hasn't been fixed at late as Version 11 (the one I'm using).  Just watch out for it when you try to use an opening book to pick a line based on its purported winning percentage.  The best approach is to use the Reference Pane, or at least double-check the continuations for a couple of further moves.

Personally, I now use the Reference window pane for this purpose, and put up with the slight lag required to update the stats for every new position in the game.  I use an AMD Quad processor at 2.9 GHz, so if you have something less powerful, you might feel the pinch a little more.

I'm not excessively critical of the ChessBase software in general; I use many of the features quite effectively. But a few of them have known faults you should know how to work around.

Another example: Try using a position search in a database; ignore the results. Then, edit the position within the search filter (add, move, delete pieces, whatever), make a note of the new position you're now searching for, and run the search again. Save the resulting list of games.  Now, reset the search filter completely (I suggest closing and reopening the database as well). Finally, set up the (altered) search position again from scratch, and run the search a 3rd time. The results from the 2nd (edited position) and 3rd (fresh position) searches should match. They frequently do not.  I've noted many cases where the fresh search filter returned many more games than the edited search filter.  I have no explanation for this, but I no longer edit the position in the search filter.  I always create a fresh position (usually by copying and pasting from a game window I set up for the purpose).

Hope this is helpful!


Abbreviations like 't', 'm', 'zt', 'sf' in chess databases I am just cleaning up the Event and Site headers in the games in my chess database.
There are a lot of abbreviations there. I am relatively sure about the following:

of, qf, sf and f – octo final, quarter final, semi final and final.
zt and izt  – zonal tournament and interzonal tournament.

But I could need help with these:

tt – Transnational Tournament? Training Tournament?
m (also: mt) – Masters? Match? Men? Memorial?
Tch – Transnational Championship?
It – Invitational Tournament? Italia?

Any hints are appreciated.

Wikipedia says TT is Transposition Table...
When the search encounters a transposition, it is beneficial to 'remember' what was determined last time the position was examined, rather than redoing the entire search again. For this reason, chess programs have a transposition table, which is a large hash table storing information about positions previously searched, how deeply they were searched, and what we concluded about them. Even if the depth (draft) of the related transposition table entry is not big enough, or does not contain the right bound for a cutoff, a best (or good enough) move from a previous search can improve move ordering, and save search time. This is especially true inside an iterative deepening framework, where one gains valuable table hits from previous iterations.
IT seems to hint at Invitational Tournament, though I cannot confirm this.


Initial FIDE rating below floor, what happens? I'm curious to know what happens in the following scenario:
I play a Swiss tournament and meet 3 rated players, I score at least half point but do badly overall. Then I play another Swiss tournament and meet another 3 rated players and do better this time.
Overall, my initial rating is below the rating floor of 1000 because of how badly I played against the first 3 rated players, and rating is not published.
My questions are:

Are my first 6 results discarded and I have to play 5 new rated opponents?
If yes to (1), do I have to score at least half a point in a tournament again before my results are considered for my initial rating?
If no to (1), are all of my first 6 results kept, forcing me to keep playing until I have pooled enough results to be above the floor of 1000 within 26 months?

Follow up scenario:
Assume the same thing happens as above, but I played 3 rated players in my first tournament and 6 in the second. My performance in the first one is terrible, but I did well in the second. If you pooled all 9 games, my rating would be below the floor, but if you only looked at my last 6 games, my rating would be above the floor.
What happens in this case?

The rules FIDE use in calculating a player's first rating are outlined in the FIDE Rating Regulations effective from 1 July 2017.
The relevant sections are:

6.1 If an unrated player scores zero in his first tournament, his score and that of his opponents against him are disregarded. Otherwise if an unrated player has played rated games, then this result is included in computing his overall rating

and

7.14 A rating for a player new to the list shall be published only if it meets the following criteria:
7.14a If based on results obtained under 6.3, a minimum of 5 games.
7.14b If based on results obtained under 6.4, a minimum of 5 games played against rated opponents.
7.14c The condition of a minimum of 5 games need not be met in one tournament. Results from other tournaments played within consecutive rating periods of not more than 26 months are pooled to obtain the initial rating.
7.14d The rating is at least 1000.
7.14e The rating is calculated using all his results as if they were played in one tournament (it is not published until he has played at least 5 games) by using all the rating data available.

So, the answers to your questions are clear:

Are my first 6 results discarded and I have to play 5 new rated
opponents?

Since you scored more than zero in your first tournament then all the results will be used in calculating your rating provided they were played within a 26 month window. So, provided 26 months have not elapsed then the answer is "No".

If yes to (1), do I have to score at least half a point in a
tournament again before my results are considered for my initial
rating?

If your next tournament was more than 26 months after the first two (i.e. "yes to (1)) then that counts as your first tournament and the rule regarding scoring zero in your first tournament applies.

If no to (1), are all of my first 6 results kept, forcing me to keep
playing until I have pooled enough results to be above the floor of
1000 within 26 months?

According to 7.14e the answer is yes with the 26 month proviso. Every time an old tournament drops out of the 26 month window it is excluded from your results.


Was playing with both hands ever allowed in chess? I was watching this video on Youtube of an Armageddon game between Vladimir Kramnik and Garry Kasparov which happened in 1995. It can be seen that Kasparov is using both of his hands for some moves. (For example, around the times 9:39, and 9:48)

My understanding is this is illegal.
 Why is it allowed here?

Was this legal in the past? Or is it legal in any format of chess like Armageddon here?

Was playing with both hands ever allowed in chess?

Yes, before 1997. Hence in 1995 Kasparov was not breaking the rules.

The key article in the the FIDE Laws of Chess is:

  Article 4: The act of moving the pieces

  4.1   Each move must be made with one hand only.

This first appeared in the 1997 edition of the FIDE Laws of Chess.

The previous edition, in 1993, did not have this rule.


How to write an interface to lichess for a millenium board using chesslink? I am aware of the python chess and chesslink mchess work but would like to attempt to interface it with lichess.org.  My purpose would be to play others on lichess using my Millenium board.
 The API's I've found for lichess seem to be for a chess engine interface rather than external hardware.  Any guidelines on where to find other similar work (like how DGT may do it)?

As you've seen, the Lichess API only allows bots to use the API functions that make moves in an ongoing game.  As far as I can tell, this is intentional; the API requires that anything that can generate moves in a game by some means other than human interaction on the Lichess site must be flagged as a bot.

Which means (again, as far as I can tell...), the only way to do what you want to do would be to create some kind of intermediary between the e-board and Lichess that actually mimics the actions a human would take during a game (such as simulating mouse clicking and movement on a game's web page).

I personally would not know where to start if I were trying to do this, and I also don't know if doing something like this would trip Lichess's anti-cheating detection in any way.  But it appears that this is what you'd have to do in order to play on Lichess using an e-board.


Why I did not see the first-mover advantage in my game history? I have played over a thousand blitz games at chess.com and here are the results:

I failed to notice any obvious difference between white and black. In other word, I do not see the the first-mover advantage in my game history at all.

What are the possible reasons that the the first-mover advantage is not reflected in my game history?
If playing white does not give me an advantage, should I play the Saragossa opening and play as if I am playing black (Slav with one extra tempo, Caro-Kann with one extra tempo, etc.) when I am actually playing white?

The advantage White gets in a game is so small that it becomes completely irrelevant at low levels.
What is the point of having such edge on your opponent if you at least are going to make an inaccuracy in the opening or middlegame?
Furthermore, in blitz games that small advantage is probably negligible since a greater deal of mistakes are made.

My online rating in lichess is today close to 1700 and I see this in my games all the time. I do OK until a certain move (or later on) but due to something I cannot understand, I lose that +1 advantage I had accomplished before.

All in all, I do not think you should expect to have a greater percentage of wins as White unless you are above 2000 because below that, mistakes make the players constantly lose the upper hand they managed to acquire.
At higher levels, masters are more likely to capitalize on small advantages and turn the game into a win.


Could you help me to find which game this is? When I was a kid, I remember reading a newspaper article about a chess game. The article was written as if the writer was one of the players. It was a pretty surprising game and it looked as if it was a total domination. The article was like this:

  I was just picking up the free pieces. I was so confident that I was
  dominating the board. I saw him writing "resign" in the notation
  paper. To make him more desperate, I took his rook with my bishop. I
  was waiting for him to flick his king. Then suddenly, he scratched the
  word "resign" and has written "Re8" instead. Then it hit me. I was
  losing.

The article I have read was a long time ago therefore I might be wrong about Re8.

Is this a famous game? If you know which game this is, can you help me?

https://www.chess.com/article/view/how-to-avoid-blunders-part-two

In one of his books GM Alexander Kotov even coined a term "Dizziness due to success" which describes Chigorin's blunder that we just witnessed pretty accurately. Kotov even tells his own story. He was playing a game and achieved a completely winning position. His opponent lost any interest in his game, and mostly watched the games of other players. Moreover, he wrote "White resigned" on his score sheet, folded it and put it in his pocket.  Kotov knew that his opponent was just waiting for a good moment to stop the clock and concede the defeat.  Fortunately, such a moment was very close and Kotov took the White Bishop on f7. Guess what happened after that.
When Kotov's opponent executed his winning move, he took his score sheet out of his pocket, crossed out "White resigned" and it was Black who had to resign the game. It doesn't even matter to me if the White player did this little trick (with folding his score sheet) on purpose or he genuinely thought that the game was over.  The point is once you start thinking that the game is over and your opponent is about to resign, blunders are almost unavoidable!


In the open Catalan, should Black hold onto their pawn? In the open Catalan, Black can hold onto the c4-pawn with b7-b5 and a7-a6. If so, then the queenside will have to be severely weakened. I think that this approach is reasonable and playable, but many other chess players state that it isn't good. Where could my reasoning have gone wrong?

It's possible to keep the pawn but at the expense of seriously weakening the queenside and fall behind in development. Keeping the pawn is certainly playable but you will need to know how not to be busted in the centre.
Keeping or giving the pawn, both possible in Catalan. Whether you like it or not depend on your personal preference.


Worth of a piece in time Let us say that two players are playing each other. The are supposed to be in the same level (You can take that as an equal longtime ELO). They might be playing blitz, or rapid. But suddently, one of them blunders a pawn. Too bad. But the guy with one less pawn has more time. Is he compensated?

So to clear this out:

Is there a formula, supposing that the pieces have the following values:

Pawn - 1
Knight/Bishop - 3
Rook - 5
Queen - 9

And that there is a time difference between both players.

Regarding all factors, so remaining time for both players, increment, is there a formula that calculates what a piece is worth in time?

Increment will be a very important factor to consider. Because increment can save you if you have a very small amount of time.

Also the results cannot be precise to the maximum. We will suppose that the position would be equal if the lost piece was suddenly there. So 0.00.

Please ask me in the comments if you need any extra details.

EDIT:

In the comments it was noted to me that a passed pawn position could be fatal. So I am adding this condition:

The position will be valued by an computer program as 1.00 if a pawn is lost, 3.00 if a knight/bishop is lost, etc. This is to limit the search to games where the win is still unclear.

This question can hardly have an objective answer, as the time controls and the strength of the players both matter a lot while valuing material and time management. A partial answer would be given assuming a time control of 1 minute. For this time control, regardless of the strength of the players, we can safely say that on lost positions the knight is the most valuable piece (after the queen). This is stated many times by IM Daniel Rensch on his Bullet Brawl Series.

When the player possessing the knight has more time, this difference is accentuated as he may look for tricks and swindles to try to make his opponent blunder or even lose on time. The forking ability of the knight is what makes it such a good piece in bullet, as some times the fork occurs and the knight cannot even be captured after he wins one of the forked pieces. This advantage is almost completely nullified when there is some kind of increment, allowing the players to take their time and think a bit more about the position.


Why doesn't white take after 8..c5 in the Grünfeld, Spassky variation? I was looking through the titular variation and am confused why there are no master games with 9.dxc5. Is it simply because white doesn't want to give up the central pawn, even if they can gain a material advantage? Is that pawn that valuable in this type of game? I'd also guess that maybe the material advantage is pretty temporary since it will be hard to defend the c pawn afterward.

Opening as follows:

[fen ""]
1. d4 Nf6
2. c4 g6
3. Nc3 d5
4. cxd5 Nxd5
5. e4 Nxc3
6. bxc3 Bg7
7. Bc4 O-O
8. Ne2 c5

Thanks.

9.dxc5? is a horrible positional blunder.

The Grunfeld for black allows white a big center, and his idea is to chip away at it, or force it to advance, and then chip away at it. That center controls a lot of nice squares, and is very desirable. 9.dxc5? by white voluntarily does what black is trying to achieve in a very bad way, and worse, it turns the Bg7 into a monster. In exchange for that, you cannot even keep the pawn as black can win it two ways. It is so bad that in 5099 games in the Mega 2020 database, no one has ever played it. In addition, the eval on Stockfish goes from about +.70 to -.67 instantly.

Black can win back the pawn with Qa5, but even stronger is 9...Nd7, and the N will have an incredible c5 square as its base. I have added notes to the following line regarding other positional advantages, so be sure to read them.

 [FEN ""]

 1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7 7. Bc4 O-O 8. Ne2 c5 9. dxc5? Nd7 10. O-O (10. c6 Ne5 $1 11. Qxd8 (11. cxb7 Qxd1+ 12. Kxd1 Bxb7 13. Bb3 Nd3 14. Be3 Rac8 15. Kc2 Rfd8 {There are a million ways white can play from here, but they are all losing and black is all over him.}) 11... Rxd8 {And the N gets to d3 with great effect positionally or this...} 12. c7 Rd7 13. Bb5 Rxc7 {With a huge advantage.}) 10... Nxc5 11. Qc2 Bd7 12. Rd1 Qc7 {And white has big problems down the c-file, the Bc4 is in danger (if black trades for it, the two bishops are a winning advantage in this open position), and the Ne2 is not even well-placed.}


Do you get rating points if the other player just leaves an online game and loses on time? Some sites, eg chessbase,  seem to have players that won't resign but either just leave for coffee until their clock runs out, or else they wait a minute then start another game so you have to ask the arbiter to declare the game won for you.
Not much we can do about impolite players, but ChessBase does not show any points won in this case. Today I beat a much higher rated player in 9 moves so I can understand their annoyance at playing like a patzer who just learned the moves today and their action was to stall a bit then just disconnect from this game while their clock still ran.
I got the arbiter to decide this time, but sometimes you have to wait until the entire clock runs down in case they come back at the very end to move and hope you left and your clock runs out.

I haven't played on Chessbase for quite some time, but generally loss on time through disconnect is still a loss and loses rating accordingly. Otherwise too many people would just disconnect, obviously.
Lichess punishes people who let the time run out with a ban (after several such incidents), so it might be less of a problem there.


Why Qd1 is the best move? As per subject, why Qd1 is the best move and all other moves for queen like Qd2 and Qd3 are not? I understand that it’s important to cover d column but why 1 and not 2 or 3?

Also why Rd1 is not a good move?

Qd1 hits the bishop on d6 and the knight on h5. One of those will be won.

Btw, I think this a famous game between Larry Christiansen and Anatoly Karpov. Famous, of course for this early blunder. Here, you can see the whole game and maybe find out more about the players.


Pawn gambits "For The Win" Possibly confirmation bias, but I often find a game I've won involved the loss (intentional or otherwise) of a pawn, which has opened up a file for rook attack, particularly on b/g files.  Is there any catch-all term for this sort of gambit other than this title?  I wonder if anyone has statistically analysed this type of scenario.

It is called a clearance sacrifice:

In a clearance sacrifice, the sacrificing player aims to vacate the
square the sacrificed piece stood on, either to open up lines for his
own pieces, or to put another, more useful piece on the same square.


Why 6...e5 in King's Indian? I'm a hobbyist chess player, mostly playing online correspondence. I often play the King's Indian defense as Black, but there seems to be a key idea in the opening that I'm missing. Specifically, I don't understand why 6...e5 is so commonly played in so many variations, for example:

[fen ""]
[StartFlipped "1"]
1. d4 Nf6
2. c4 g6
3. Nc3 Bg7
4. e4 d6
5. Nf3 O-O
6. Be2 e5

It seems to me that in this position by playing 6...e5 Black blocks his own fianchettoed bishop, and given that White frequently pushes d5 later on, the diagonal is unlikely to reopen up any time soon. It seems to me that something like 6...c5 would be a much more natural move, logically setting up a queenside attack with the central pawn chain supporting the dark-squared bishop on the long diagonal.

Clearly I'm missing something here, given 6...e5's popularity relative to 6...c5. So my questions are

Why is 6....e5 so much more popular than 6...c5, and
What is Black supposed to do with his dark-squared bishop after 6...e5?

It is good to think more concretely here. After move like e5 three things can happen. White can take on e5, white can play d5 or black will one day play exd4 himself.

Taking on e5 never wins a pawn and creates a hole on d4. For good reason not very popular
With d5 your bishop is now bad, but the position for black is good, easy and funny to play. An attack with f5 f4 g5 h5 g4 Ng6 Nh4 is very dangerous. Bishop often joins the attack in later stages from h6 and is often use on f8 till its time to hold the queenside for a little longer. Also maneuver Rf8-f7-g7 us typical to protect 7th rank and attack at the same time. Find games of Nakamura how he murdered some 2700+ players just rolling on the kingside.
Tactics say it is not so easy for white to achieve exchange on d4 under good terms. After 7...Nc6 there are no useful moves for white and pressure against centre is already too strong. Popular d5 goes to (2) and Be3 runs to Ng4, even if it is also variation.

So there are three good scenarios for black after e5 and in comparison to some Maroczy bind or benoni structure I think they are both better and more interesting to play.

Note1: Many c5 style players play c5 already on move 2, by the way.

Note2: Calm players with no intention of attacking don't play kings indian in the first place, playing Nimzo Indian, Slav etc...

So everybody wants to play e5 and win!


Why is it a mistake to trap this bishop? In the below position, I played pawn from g7 to g5, trapping the white bishop. The computer didn't like that at all, and gives white a huge advantage. Instead, it wanted me to just simply develop my light-squared bishop.

What is wrong with my move?

You get a bishop in exchange two pawns and initiative for white piece.

This is the explanation: After you go to g5, your opponent can play knight takes g5 and if you recapture the knight with your pawn, queen opponent will go to h5 and it is a check. Your pawn on g5 will be captured in the next move by your opponent queen.
Black position is vulnerable and d5 pawn is the weakness that can be exploited by white.


Computer chess endgame Again , this is an interesting position I need help to solve. In a game Stockfish vs Ethereal , Stockfish was ahead , but Ethereal could have found  refuge in the following endgame. Is the position winning for White anyway? Could Black steer it into a positional draw?
[White "Stockfish"]
[Black "Ethereal"]
[FEN "4b3/4N1k1/3R3p/r7/8/P6P/5KP1/8 b - - 0 1"]

I am unsure what version of Stockfish you were using so I ran analysis 12 times; 4 seperate engines for each version of Stockfish.

Stockfish 10 vs ( Ethereal , Komodo, LC0 , Stockfish 12 )
Stockfish 11 vs ( Ethereal , Komodo, LC0 , Stockfish 12 )
Stockfish 12 vs ( Ethereal , Komodo, LC0 , Stockfish 12 )

Results were Stockfish (white) at the end of 20+ moves, was in a stronger position in all 9 instances. Based off this, I would suggest black is in a losing and in a irrecoverable position. There is the potential for a draw but it appears extremely unlikely.
The best variation / playout that I saw, that had the best end position for black, was Stockfish 12 vs Stockfish 12. +-3.03 / 41 so white is decisively better.
Issue with engine games in these sort of positions are the gameplay is boring. That being said, I have attached it for reference though.
[White "Stockfish 12"]
[Black "Stockfish 12"]
[FEN "4b3/4N1k1/3R3p/r7/8/P6P/5KP1/8 b - - 0 1"]

1... h5 2. Rd3 Kh6 3. Kg1 Kg7 4. Rc3 Kf7 5. Nc8 Kf6 6. Nd6 Bg6 7. Kh2 Ra4 8. Rf3+ Kg5 9. Nb5 Kh6 10. Nc7 Ra5 11. Ne6 Bf5 12. Re3 Bg6 13. Rc3 Bf7 14. Nf4 Kg5 15. Ne2 Ra4 16. Rf3 Bg6 17. Rg3+ Kh6 18. Rc3 Be4 19. Nf4 Ba8 20. Ne6 Ra5 21. Nc5 Bd5 22. Nd3 Ra4 23. Nb4 Be4 24. Re3

From my experience with engine games this is going to continue on for some time. Eventually the Black h pawn and Whites a pawns will go (will likely also involve trading out the bishops somewhere ) , white with the pawn advantage will promote.


How does Allie's search algorithm work? Allie is a strong engine that's looking competitive with the top ones (Leela Chess Zero and Stockfish). It's supposedly based off AlphaZero, but works differently. As far as I understand it, the most important difference is the search algorithm. The author said in a March 2019 interview that:

  AT: To begin the tournament, Allie will perform MCTS based search with absolute fpu where new nodes start off with win pct of -1. The search is modeled after Deepminds paper’s. As I said above, I’m hoping to switch to AlphaBeta for the long term direction of the project. I’ve experimented with many, many ways of doing this with the networks generated by the Lc0 project and I think I’ve hit upon a way to achieve the depths required to maintain ELO level with MCTS based search, but it is not ready yet. In the future, I imagine we’ll see a lot of experimentation with different variations of search (mcts, ab) + eval (handwritten, NN) in computer chess engines. Hoping to be a part of that and to contribute to the shared pool of knowledge.

(Emphasis mine.) As of time of writing the Allie Github page says:

  Well, I was inspired during the original CCC to see if you could pair traditional Minimax/AlphaBeta search with an NN. This is still her main purpose and the focus going forward. However, the initial versions were using a similar pure MCTS algorithm as Lc0 and AlphaZero. The current versions of Allie use a modified hybrid search of Minimax and Monte Carlo.

I don't understand what "modified hybrid search of Minimax and Monte Carlo" means. Can someone explain? I know what each of these terms mean, but I don't understand the combination.

Allie's search is a combination of MCTS and Minimax. The MCTS is very much like you would find in AlphaZero or LC0 as it was taken from the same papers. In addition to MCTS, Allie also does a minimax based backup of the tree whenever a new MCTS batch is evaluated by the NN. This minimax backup is then used to modify the Q values of the nodes in the tree that were either 'min' or 'max'. This modification is a further averaging of the MCTS based backups.

So:

Allie uses MCTS for playouts and for back prop in much the same way as A0 and Lc0
Allie also does a minimax-based back prop to supplement that mcts based back prop

I've also tried many, many, many, different ways of adding newer AB/Minimax to the algorithm, but so far nothing that has successfully gained elo over the above. Finally, I'll note that in all of my testing of Allie (pure MCTS) vs Allie (MCTS+Minimax) the latter has scored significantly higher so I am confident that it does improve elo at least in self play.

UPDATE:

Since I wrote this, the Allie minimax backup has grown more complicated. Now, in positions where the best candidate move is a terminal node Allie does a pure minimax based backup with no mcts averaging. If the best is proven best among all of its siblings, then the parent is also made terminal and assigned the inverse score of the best child. If the best is not proven, then it still does pure minimax backup, but the parent continues to be expanded and if a sibling becomes best it switches back to the combination of minimax+mcts backup. Finally, this is all kept track of for transpositions too.


In the opening stage, can we determine that one move is better than another by looking at winning percentage? After  1.c4 Nf6 2. Nc3 g6, thousands of games have been played with the following two moves of white: 3.g3 and 3.e4. It seems that the winning percentage suggested that 3.e4 is clearly better than 3.g3, though interestingly, more games are played after 3.g3 than 3.e4.

    [fen ""]
1.c4 Nf6 2. Nc3 g6

So my question is that, can one conclude that 3.e4 is better than 3.g3 based on the winning percentage?

Similarly, in a position where thousands of games have been played, if say after Move A white's winning percentage is significantly higher than after Move B (say by 5%) and at the same time, the winning percentage for black is significantly lower, is it sufficient to conclude that Move A is better than Move B?

The precise answer depends largely on the database, and the answer is still never yes.

If the database includes any players below 2500ish OR it includes blitz or rapid time controls, do NOT attempt to rely on these percentages. Inaccurate moves were likely played and possibly "moved to the top" of the possible moves.

You could possibly rely on percentages for main lines with high rated players and long games, but it's still a little risky.

I would recommend looking instead at established opening theory books/websites as well as Stockfish.


Three-fold repetition and null move Added transposition table (this was tested alone and worked as expected), three fold repetition and null move pruning in my engine and wins more games but some of them end with three fold repetition even in win positions, played against the previous version

I keep a table history to save the current state of the board before making the move, to save the current zobrist key, move, en passant and castling

In make null function I just hash the en passant if exists, switch side, hash it and increment the fiftymove counter

To check for repetitions I do this:

int i;
for (i = 4; i <= board->fiifty_move; i += 2) {
    if (board->zkey == board->history[board->ply - i].zkey) {
        return true;
    }
}

The question is when checking for repetition it will check also for null move positions, is that correct? If a null move is repeated can we take that as a move even that null move it just switching sides?

I've seen engines that has a array like: hist_rep[index++].zkey = curr_zkey; that is only to check for repetitions and the array is not filled in the make null move function

Others engines has a counter inside the repetition function to check if the position has been repeated before more than one time

for (...) {
    if (zkey[i] == curr_zkey) ++rep;
    if (rep == 2) return true;
}

What is the correct way?

No. You shouldn't count null-move in repetitions because:

Null-move is fake
Null-move artificially creates a repetition when there is none

Your implementation is correct, but you might want to exclude null-move. Let's take a look at Stockfish:

  https://github.com/official-stockfish/Stockfish/blob/master/src/position.cpp

bool Position::is_draw(int ply) const {

  if (st->rule50 > 99 && (!checkers() || MoveList<LEGAL>(*this).size()))
      return true;

  int end = std::min(st->rule50, st->pliesFromNull);

  if (end < 4)
    return false;

  StateInfo* stp = st->previous->previous;
  int cnt = 0;

  for (int i = 4; i <= end; i += 2)
  {
      stp = stp->previous->previous;

      // At root position ply is 1, so return a draw score if a position
      // repeats once earlier but after or at the root, or repeats twice
      // strictly before the root.
      if (   stp->key == st->key
          && ++cnt + (ply - i > 0) == 2)
          return true;
  }

  return false;
}

You already have st->rule50 in your code (board->fifty-move) but you don't have st->pliesFromNull.

Let's check what Stockfish author said about pilesFromNull.

  http://www.talkchess.com/forum/viewtopic.php?start=0&t=35052&topic_view=flat&sid=46a5561bcd0c4d36796c0fbfe5158079

By Joona Kiiski (2010):

They are already excluded, note the use of st->pliesFromNull:

Null moves can artificially create a repetition
draw where instead there is no one.

So use a second counter to reset history after a null move.

You see, if the strongest engine in the world does it you have no reason for not doing it.

If you check the code carefully, the first time when you do a null-move pliesFromNull is 0.

void Position::do_null_move(StateInfo& newSt) {
    ....
    st->pliesFromNull = 0;
}

later the engine increments the counter in do_move:

++st->pliesFromNull;


Why is it important to study classical games? Many masters have always recommended the study of classical games. Why is it important to study them and what is so special about classical games?

There are a variety of reasons:

Regardless of when they were played, there is always a lot to learn in analyzing better players's games.
Players from a century ago often used simpler strategical themes that are easier to understand and apply.
Opening theory was not that well developed back then, so the "actual game" starts earlier on. You also wouldn't find any "weird" moves that are justified by some obscure tactical sequence that only a computer can see.
Games between masters were, unlike today, rarely decided by at-home preparation.
Old masters had an awesome endgame technique.
The opposition was often weaker than today, so masters could execute their plan in a "pure" form. In more modern games, the main plan is most of the time hidden behind counterplay, counters to that counterplay, and so on...
A final point would be that these games have been reviewed multiple times by a lot of different people, each of them making their contribution


Arbiter ignored cheating, and I signed the scoresheet. Did I lose my right to object? I am currently playing in an ELO tournament.

Today, while I was playing, my opponent occasionally got up and walked around. At first, I did not care much. Then, I realized that some people were behind me, examining the game very carefully.

At the moment there was a critical position, my opponent was not at the board, and three or four guys came around, and began to speak among themselves. I looked for an arbiter but there was only one and he was sitting at the other end of the tournament room.

I made my move, and went to the arbiter. This is when the weird things happen. I told the arbiter that my opponent is never at the board, and there are some people coming when he's away. There are cameras everywhere, so he is free to check.

When I and arbiter were walking back, there were three people around the board, talking to each other and pointing at the game, and my opponent was also at the board, listening to them.

I immediately said that I demand a rematch at the least, since this is not the first time. Arbiter spoke to my opponent and his response was "he said that they were speaking about something else, I warned him, and this will not repeat again."

He also told me that if I don't sign the scoresheet, it counts as I did not play the game, and I cannot claim anything. So, I completed the game, signed the sheet, and told the arbiter that I will write this to FIDE.

I have written a mail describing this situation. But I'm not sure if something will change. In case such situation happens again, how should I proceed?

According to the 2017 version of the Laws of Chess, rule 11.10 says:

  Unless the regulations of an event specify otherwise, a player may
  appeal against any decision of the arbiter, even if the player has
  signed the scoresheet (see Article 8.7).


pgn-extract program troubleshoot Anyone familiar with the program pgn-extract to possibly help with a little troubleshooting?  I have tried to look through manual of the program and I am coming at a loss with addressing the issue.  I have tried using pgn-extract program commands -C, -N, -V with no affect. Here's the following line from my .bat file.

https://www.cs.kent.ac.uk/people/staff/djb/pgn-extract/help.html for manual reference.

Objective-I am trying to clean up a .pgn file that was created by combining multiple .pgn files together via either dos commands.

  copy *.pgn newfile.pgn

or

  copy /b *.pgn newfile.pgn

Issue-.pgn code errors.  In both attempts at combining multiple .pgn files I get similar errors.  See screenshots.

improper header spacing examples(text editor used is Brackets).  This is causing a variance in multiple GUI's calculation of total games in the database.  Preferred fix would be to use pgn-extractor to clean the pgn file by properly placing the header of the next game in the proper position below the previous game so the GUI can correctly count total games.  I know how to manually fix this but I'm also building a separate opening book that will have a thousands of games in and in case this issue happens with that, would like to find a fix beforehand.

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

David


What are the shortest possible games with a) 20 Bishops, b) 20 Knights, and c) 20 Rooks? The fastest way to get to 18 queens is known. But what are the shortest possible games with a) 20 Bishops, b) 20 Knights, and c) 20 Rooks?
Here are my own attempts. Can anybody find/create a faster way?

[Title "20 Rooks-104 Ply, me, chess.stackexchange.com 3/31/2019, Non-Unique Proof Game In 52.0 Moves"]
[FEN ""]
[startply "104"]

1. b4 d5 2. g4 e5 3. h4 f5 4. a4 c5 5. c4 d4 6. f4 e4 7. Nf3 exf3 8. Nc3 dxc3 9. d4 a5 10. e4 h5 11. b5 Na6 12. g5 Nh6 13. bxa6 b5 14. gxh6 g5 15. d5 b4 16. e5 g4 17. Bd3 Bd7 18. Be4 Bb5 19. Qd4 Qg5 20. axb5 fxe4 21. hxg5 cxd4 22. g6 h4 23. g7 h3 24. f5 g3 25. f6 g2 26. Kf2 Kf7 27. Kg3 Kg6 28. Rh2 Rh7 29. g8=R+ Rg7 30. h7 g1=R+ 31. Rg2 h2 32. f7 f2 33. e6 e3 34. e7 e2 35. exf8=R h1=R 36. Re8 f1=R 37. f8=R e1=R 38. h8=R b3 39. b6 b2 40. b7 Ra7 41. Ra2 bxc1=R 42. b8=R Rb1 43. Rab2 Rab7 44. a7 d3 45. d6 d2 46. c5 c2 47. c6 a4 48. c7 a3 49. d7 a2 50. a8=R a1=R 51. c8=R c1=R 52. d8=R d1=R

 [Title "20 Bishops-104 Ply, me, chess.stackexchange.com 3/31/2019, Non-Unique Proof Game In 52.0 Moves"]
 [FEN ""]
[startply "104"]

1. g4 h5 2. g5 Rh6 3. gxh6 g5 4. h4 g4 5. b4 e5 6. f4 e4 7. Nf3 exf3 8. e4 f5 9. e5 Qg5 10. Nc3 a5 11. Ne4 fxe4 12. c4 a4 13.Qb3 axb3 14. a4 b5 15. a5 d5 16. c5 Ra6 17. hxg5 Rd6 18. cxd6 c5 19. Ra4 c4 20. d4 Na6 21. Be3 Nc5 22. dxc5 bxa4 23. g6 g3 24. h7 h4 25. g7 h3 26. b5 g2 27. Kf2 Kf7 28. f5 c3 29. f6 Kg6 30. Kg3 gxh1=B 31. a6 a3 32. a7 a2 33. b6 b2 34. b7 c2 35. c6 d4 36. c7 f2 37. Ba6 f1=B 38. Bf2 e3 39. a8=B Bhg2 40. b8=B h2 41. hxg8=B d3 42. Bb3 d2 43. g8=B Bh6 44. f7 e2 45. d7 a1=B 46. f8=B b1=B 47. d8=B Be6 48. c8=B Bf7 49. e6 c1=B 50. e7 d1=B 51. e8=B e1=B 52. Ba2 h1=B

[Title "20 Knights-104 Ply, me, chess.stackexchange.com 3/31/2019, Non-Unique Proof Game In 52.0 Moves"]
[FEN ""]
[startply "104"]

1. d4 c5 2. f4 e5 3. f5 d5 4. Bf4 Be6 5. fxe6 exf4 6. e4 f5 7. e5 c4 8. Bd3 Bc5 9. dxc5 cxd3 10. c4 a5 11. b4 a4 12. Qb3 axb3 13. a4 b5 14. a5 h5 15. g4 Rh6 16. g5 d4 17. gxh6 g5 18. h4 g4 19. Ra4 Qg5 20. hxg5 bxa4 21. Kf2 d2 22. e7 f3 23. g6 d3 24. g7 Kf7 25. Ke3 Kg6 26. Kd4 f4 27. e6 h4 28. h7 b2 29. a6 a3 30. b5 a2 31. b6 f2 32. c6 f3 33. c7 g3 34. a7 g2 35. b7 h3 36. c5 h2 37. c6 Kf5 38. Nh3 Na6 39. Na3 Nh6 40. bxa8=N gxh1=N 41. c8=N d1=N 42. e8=N f1=N 43. g8=N b1=N 44. h8=N a1=N 45. c7 d2 46. e7 f2 47. Nef6 Nb2 48. Ncb6 Nfg3 49. c8=N f1=N 50. e8=N d1=N 51. Nac7 Nhf2 52. a8=N h1=N

Addendum 1/9/2021: In a Computer Chess Club archives page that I came across today, I found some holy grails! The thread author Eduard Nemeth posted four proof games, all from 1997 and by Zoltan Blazsik, for 18 queens and 20 rook, bishops, and knights.
The bishop and knight games are faster than mine-new records! However, my 104 ply for 20 rooks remains untouched.
[Title "20 Knights-100 Ply, Zoltan Blazsik, 1997, Non-Unique Proof Game In 50.0 Moves"]
[FEN ""]
[startply "100"]

1. h4 g5 2. h5 g4 3. h6 Bg7 4. Rh3 gxh3 5. hxg7 h5 6. b4 a5 7. b5 Ra6 8. bxa6 a4 9. a7 a3 10. Bb2 axb2 11. a4 h2 12. g4 e5 13. f4 d5 14. e4 Be6 15. f5 h4 16. fxe6 f5 17. g5 h3 18. c4 Qd6 19. c5 f4 20. cxd6 c5 21. Bc4 dxc4 22. d4 c3 23. d5 c4 24. Qd4 exd4 25. a5 bxa1=N 26. a8=N c2 27. a6 c1=N 28. a7 c3 29. gxh8=N b5 30. Nb6 b4 31. a8=N b3 32. Na3 b2 33. e5 b1=N 34. g6 Na2 35. g7 Nh6 36. g8=N c2 37. d7+ Kf8 38. d8=N c1=N 39. e7+ Kg7 40. d6 h1=N 41. d7 h2 42. Nb7 d3 43. d8=N d2+ 44. Kf1 f3 45. e8=N+ Kh7 46. e6 f2 47. Kg2 d1=N 48. Nec7 f1=N 49. e7 Nhf2 50. e8=N h1=N

[Title "20 Bishops-100 Ply, Zoltan Blazsik, 1997, Non-Unique Proof Game In 50.0 Moves"]
[FEN ""]
[startply "100"]

1. a4 b5 2. a5 c5 3. Ra3 b4 4. d4 Qb6 5. axb6 a5 6. d5 Nc6 7. dxc6 bxa3 8. b4 a4 9. b5 c4 10. Nd2 c3 11. e4 f5 12. e5 Nf6 13. exf6 f4 14. g4 h5 15. g5 Rh6 16. gxh6 g5 17. h7 g4 18. h4 g3 19. Qg4 hxg4 20. h5 g2 21. h6 gxh1=B 22. Ne2 f3 23. h8=B fxe2 24. f4 g3 25. b7 g2 26. f5 e5 27. bxa8=B cxd2+ 28. Kf2 a2 29. c4 a1=B 30. b6 d5 31. b7 d4 32. c7 g1=B+ 33. Kg3 a3 34. c5 a2 35. b8=B Ba6 36. c8=B Bb2 37. c6 a1=B 38. Bcb7 d1=B 39. c7 Bb3 40. c8=B d3 41. f7+ Kd8 42. f6 Bb4 43. f8=B d2 44. Bc5 e1=B+ 45. Bf2 d1=B 46. f7 e4 47. h7 e3 48. Bg7 e2 49. h8=B Bed2 50. f8=B e1=B

Thanks to Remellion's comment that getting 16 passed pawns first isn't necessary, I shaved 2 plies off 20 knights.
Addendum 11/29/2020-With a Black king maneuver, another ply is gone.
[Title "20 Knights-101 Ply, me, chess.stackexchange.com 11/29/2020, Non-Unique Proof Game In 50.5 Moves"]
[FEN ""]
[startply "101"]

1. h4 a5 2. h5 a4 3. b4 g5 4. h6 a3 5. Bb2 Bg7 6. hxg7 axb2 7. a4 h5 8. Rh4 Ra5 9. bxa5 gxh4 10. g4 b5 11. g5 b4 12. g6 b3 13. c4 f5 14. c5 f4 15. c6 f3 16. Bg2 Bb7 17. cxb7 fxg2 18. gxh8=N bxa1=N 19. f4 c5 20. f5 c4 21. f6 c3 22. g7 b2 23. a6 h3 24. a7 h2 25. a8=N h1=N 26. a5 h4 27. a6 h3 28. a7 h2 29. e4 d5 30. d4 e5 31. Qf3 Qc7 32. Qf4 Qc5 33. dxc5 exf4 34. e5 d4 35. e6 d3 36. c6 d2+ 37. Ke2 f3+ 38. Ke3 f2 39. c7 c2 40. c8=N c1=N 41. e7 f1=N+ 42. Kd4 Na6 43. f7+ Kd7 44. e8=N Nh6 45. Nh3 g1=N 46. Na3 b1=N 47. Nac7 Nhg3 48. a8=N d1=N 49. b8=N+ Kd8 50. f8=N h1=N 51. g8=N


How to disambiguate checking moves in descriptive notation? Question: In general, is noting a check/checkmate sufficient to disambiguate moves in descriptive notation?

If for example two of the same type of piece could move to the same square, but one giving check and one not giving check while doing so, is it necessary to further distinguish between the moves when recording in descriptive notation?

Take for instance the following position:

r2k3r/pbp1bppp/1p3n2/2p3B1/3N4/2N5/PPP2PPP/2KR3R w - - 0 1

In algebraic notation, according to the FIDE Laws of Chess (Appendix C), we would write 1.Ndb5+ (or just 1.Ndb5) and 1.Ncb5. The '+' to mark checks is optional.

However in descriptive notation, what do we need to write? Is writing 1.N-N5ch for 1.Ndb5+ and 1.N-N5 for 1.Ncb5 sufficiently clear, or do we need to specify 1.N(Q)-N5ch and 1.N(B)-N5?

Further test cases to justify responses with:

1.Bb5+ and 1.Bg5: 1.B-N5ch and 1.B-N5, or 1.B-QN5ch and 1.B-KN5?

rnbqkb1r/pp3ppp/3ppn2/8/3NP3/2N5/PPP2PPP/R1BQKB1R w KQkq - 0 1

1.Qa8+ and 1.Qh8#: 1.Q-R8ch and 1.Q-R8 mate, or 1.Q-QR8ch and 1.Q-KR8 mate?

5k2/8/4K3/8/8/8/8/7Q w - - 0 1

1.Bxf7+ and 1.Bxc5: 1.BxPch and 1.BxP, or 1.BxKBPch and 1.BxQBP?

r1bq1rk1/p1bn1pp1/3p1n1p/1pp3N1/4P3/1BNPBR2/PPP1Q1PP/R5K1 w - - 0 1

Citations from sources (style guides for writing descriptive notation/actual books notating such a situation) to support answers would be appreciated.

My understanding is that it's OK to use "ch" to disambiguate a move, but it's not OK to use the absence of "ch" to disambiguate. For example, in your first diagram, Ndb5 could be written as N-N5ch, but Ncb5 could not be written as simply N-N5.

I don't have a source stating that explicitly as a rule, but there is some support in Kenneth Harkness's Official Chess Handbook, "Approved by THE United States Chess Federation", David McKay Company, Inc., New York, 1967. One of the games illustrating descriptive notation goes 1 P-K4, P-K4; 2 N-KB3, P-Q3; 3 B-B4, P-KB4; 4 P-Q4, PxKP; 5 NxP, PxN; 6 Q-R5ch, K-Q2; 7 Q-B5ch, K-B3; 8 QxP(5), P-QR3; 9 P-Q5ch, K-B4; 10 B-K3ch, KxB; 11 Q-Q4ch, K-N4; 12 N-B3ch, K-R4; 13 Q-R4 mate. The caption to the third diagram on p. 94 reads (emphasis added) as follows:

  Position after 7 ...K-B3; 8 QxP(5). It is not advisable to write QxP, relying on the omission of check. QxP(5) shows that the Queen captures the Pawn on White's fifth rank.


Bullet tips and tricks Nowadays with speedy Internet and in order to play lots of opponents and to decrease the chance of cheating, people are opting for Bullet or blitz.

Generally I prefer to play Larsen opening or Double fianchetto or sometimes Ruy lopez. The traps in these openings are not in the openings but in the captures ( capturing the pawns or Knight with bishops). If the opponent is careless and pre- moves then these tricks work.

But many of the players are unaware of these things and many other gambits or trick.

If you are a pro player of bullet games what bullet-specific tricks do you use?

These tricks work much better in bullet, where flagging is probably 50% of the game, than in blitz.

The obvious one is to reply to the start of a fianchetto by threatening the square the bishop is about to move to in case it was pre-moved. e.g. reply to g3 with Bh3. Of course if your opponent didn't pre-move and your bishop is unprotected then you lose a piece but you should only do this when your opponent is playing some opening with minimal contact and with automatic moves like for instance the Kings Indian Attack with white.


Why doesn't Stockfish (DroidFish) try to flag me? Imagine the following position:

 [FEN "3k4/7p/7K/3B4/8/8/8/8 w - - 0 1"]

White is played by Stockfish in DroidFish and black by human (me). We both have 15 seconds.

After a few moves, white bishop or king gets the black pawn and... "Game over,draw by impossibility of mate!"... It is logical, due to the fact that there isn't mate position with two kings and one bishop.

I repeated the experiment sometimes and the same result happened... So, I wonder, why doesn't Stockfish flag me? Isn't it smarter to wait 50 moves for drawing with the hope to flag me without getting the pawn?

There are many possible mate positions without getting the pawn. I imagined one if pawn is promoted to knight and then: white king g3, white bishop h3, black king h1 and black knight f3. Black to move. Black knight to g1 and white bishop to g2 checkmate.

 [FEN "8/8/8/8/8/5nKB/8/7k b - - 0 1"]

 1...Ng1?? 2. Bg2#

So, it is not more logical in these cases, engines to try to flag the opponent? Maybe in a game between two engines it is meaningless, but in the case of engine vs human, I think it isn't so illogical.

What is your opinion?

They are programmed to play the best chess, and there is simply no programming added in that attempts to account for the opponent being low on time. The way it played it was the best chess-wise. A human might try to flag you, but not the computer. Personally, I like it that way.


How do top players use computers to improve their play? This question is inspired by yesterday's matches between Hikaru Nakamura + Rybka vs Stockfish. Nakamura was allowed to use an older version of Rybka to help him, and Stockfish was allowed to play with its full strength but not use an opening book or an endgame tablebase.

Question 1: How might players such as Nakamura use Rybka to improve their play against a computer opponent?

I can come up with a few naive guesses: check their own moves for blunders; check the computer's suggestions to see if there are some convoluted move sequences which lead to a huge advantage; and letting the computer play the endgame for them. This does not need to be the full story though. Maybe there are useful features that chess engines have that I am not aware of. I'm also wondering to what degree a human player would rely on his own intuition: would he always play his own moves assuming the computer never suggested a blunder or an amazing winning move which is difficult to see?

My second very similar question is inspired by a few comments by Nakamura in a reddit thread, namely

  Fischer would almost certainly lose to [people such as myself, Carlsen, and Kasparov], but this is due to the fact that the game has so fundamentally changed. If Fischer had a few years to use computers, I think he would probably be on the same level.

and

  I think mainly what can be learned from computers is a deeper understanding that almost all positions are ok with accurate play. In the past, many people assumed certain positions were automatically bad, but computers have shown that the rules and thought processes aren't always accurate!

Question 2: How have computers changed the way top players play today (when unassisted by computers)?

What is meant by the first quote? The second quote indicates that one might not want to give up too early, but does not suggest any change in playstyle.

How might players such as Nakamura use Rybka to improve their play against a computer opponent?

  ... check their own moves for blunders; check the computer's suggestions
  to see if there are some convoluted move sequences which lead to a
  huge advantage ...

I believe you said it yourself here. A computer would be used in order to check if the move that the GM thinks would be a good move is indeed the best move to exploit the existing position. I doubt that it would play the end game fully, I am positive that the GM thinks through every move of the game instead of trusting blindly the computer, but most likely definitely the opening would be played by the machine, at least till about move 5-7, until the position changes known book course.Additionally, the computer would most likely have some kind of a database of the previous games played between other players, so if the position played was already played by someone else a while back, it could be used to not make the same mistake or, vice-versa, to build a long term plan.

How have computers changed the way top players play today (when unassisted by computers)?

OK, I do understand that this might get a bit long, but bear with me. Ill bold the important points. Computers have made the modern top players much more tactically aware and ready than the chess players before them. This is what the quote about Fischer is talking about: Fischer did not have the opportunity to analyse his games and study lines to such a far extent as is done by the modern top players using computer technology. About the second quote: with the knowledge that there is a possible accurate move in virtually any position, top players would dedicate more time to thinking and finding that one single accurate move, than just assuming that the position was lost and thats it. This makes the game much more interesting and thrilling, because you know that the accurate move exists, its just the matter of finding it.

About how computers help top players prepare: so basically, theres 4 reasons why computers are used today for chess:

Playing against software program
Keeping track of games (Databases)
Using software to analyse your games
Using software to do chess problems

Out of those 4 points, the one that interest us are the bolded two.

Keeping track of games (Databases) is used usually to analyse the openings, and then comparing them to how they were played by other top-players in order to evaluate one's own position and/or learn something from others. You could've never thought that that move would bring any use, but if Kasparov's been whipping it out right and left for the past 5 years with great success, you might as well try giving it a go.

Using software to analyse your games is the primary use of computer engine by top-players. After every official game they play, the will analyse their games and see where they did wrong and where they could do better. The programs are usually proficient in tactics and opening theory, so for someone like Magnus Carlsen, whose opening is not as strong compared to other GM's like Kasparov and etc, a computer engine would be the best an fastest way to improve. And of course, if they find that what they did in game is not the strongest move in the position, next time they would be aware of it and follow the move that was suggested by the engine. Usually this would happen once again in the opening, because middle games repeat quite rarely if played against different opponents.


London System: how to defeat copying moves? I played the London system for the first time today and encountered a problem in my second game (I won my first).

[fen "rn1qkb1r/ppp1pppp/5n2/3p1b2/3P1B2/5N2/PPP1PPPP/RN1QKB1R w KQkq - 4 4"]

What is the best response to black copying your moves in the London?

If you play the London then you have to be aware and ready for favourable transpositions to other openings like the Queen's Gambit, Slav, Barry Attack (John Nunn famously lost twice to Hebden against this and then complained bitterly that the derogatory name, "Barry Attack", just rubbed salt into the wound ;-), 150, etc.

This is such a case. Here, or even on the previous move, White should be looking to play c4 for a QGD variation where the black bishop is misplaced on f5.

Check out chapter 7 Symmetrical: 2...Bf5 and 3...Bf5 of "Win with the London System" by Sverre Johnsen and Vlatko Kovacevic for more ideas.


Which interface protocol should I implement for my chess engine? I am writing a chess engine in C++ https://github.com/RomainGoussault/Deepov.

I know there are several interface protocols out there (UCI, Winboard protocol, etc) and I don't know which to implement. I would like one that:

enables my engine to play online tournaments
has several GUI for Linux, Windows and iOS
has some sort of documentation

Thanks

There're only two protocols - UCI and Winboard. Winboard is an old protocol and not really being used nowadays. Crafty is the only major engine still supporting the Winboard protocol, but it's only because the engine is also very old. UCI is a newer protocol developed by Shredder, and is used everywhere - Windows, Macs, Linux, Android, iOS etc. UCI is really the only protocol you should consider.

UCI is supported everywhere
Every chess GUI other than xboard supports UCI, such as, Chessbase, Scid, Arena etc. Even xboard can connect to a UCI engine by something known as Polyglot.
UCI documentation is at http://wbec-ridderkerk.nl/html/UCIProtocol.html

Winboard has more or less obsoleted because the protocol is more complicated than the cleaner UCI. Winboard is a stated protocol, it means the engine state depends on the previous iterations, whereas UCI is easier to deal with as you only have to supply with your current FEN or a move-list.


Maximum possible movement in a turn I've read that for any position, there are on average approximately 35 possible moves. But what's the maximum number of possible moves for a position?

After some searching, it seems that this composition is the current record holder. 218 moves; legal position with promotions:

R6R/3Q4/1Q4Q1/4Q3/2Q4Q/Q4Q2/pp1Q4/kBNN1KB1 w - - 0 1

Another version of the position (same number of moves):

3Q4/1Q4Q1/4Q3/2Q4R/Q4Q2/3Q4/1Q4Rp/1K1BBNNk w - - 0 1

Bonus:

79 moves (for black); from actual game between Davis and Panchanathan, source from Tim Krabbe's list of chess records:

4r1k1/p4pp1/2n2n1B/2b5/N6Q/P2q1N2/1r4PP/R4R1K w - - 0 1

99 moves (for white); all pieces on board:

q2Q3r/n6R/kpB1N1K1/p1p1Bppp/1PN3P1/1n1pp1b1/P1PPPP1P/r5Rb w - - 0 1

164 moves (both sides counted); all pieces on board:

R6R/pbpppK2/1B1QNNp1/1p3p1p/P1P3P1/1Pnnq1b1/2kPPPBP/r6r w - - 0 1

324 moves (both sides counted):

1QqQqQq1/r6Q/Q6q/q6Q/B2q4/q6Q/k6K/1qQ1QqRb w - - 0 1

412 moves (both sides counted); a curiosity, illegal position:

QQqQqQqq/q6Q/Q6q/q6Q/Q6q/q6Q/Q6q/QqQqQqQq w - - 0 1

Main source: Guide to Fairy Chess. The book is a bit old, so there might be new record holders, but if that's the case, I was unable to find them.


King's Indian defense: When is Nh5 the better option to prepare f5 In the position given by the moves below, checking the DB, I can see that Nh5 is far more common than Ne8. When is generally Nh5 the better idea compared to Ne8, given the weaknesses of the knight on h5, namely the fact that after black pushes f5, if white the takes exf5 and black recaptures (typically) with the g pawn, there is tactics in the air due to the fact that the black knight on h5 is now unprotected?

[FEN ""]
[Event "?"]
[Site "?"]
[Date "?"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[StartPly "7"]
1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 O-O 6.h3 e5 7.d5 *

The reason for playing ...Nh5 is to have the option of playing ...Nf4, where ...exf4 would unleash his usually bad KID bishop. Case in point is the Bayonet Attack:

[FEN ""]
[Event "?"]
[Site "?"]
[Date "?"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Nc6 8. d5 Ne7 9. b4

The main move is 9...Nh5, where in some lines black plays for ...Nf4, where a move like Bxf4 would be made worse by the fact that the absence of the b2 pawn gives even more potential to black's dark-squared bishop.

Your suspicion that the Nh5 can be loose is correct; note that in the line you describe, black needs to play ...Qe8 before going for ...f5, but on the other hand, 7...Nh5 disturbs white's position, as immediately developing the f1 bishop runs into 8...Nf4.

Generally, black would prefer ...Nh5 because it's more active; when it's not possible (say in the main line after 9.Ne1), ...Nd7 works to slow down white's c5, and ...Ne8 allows it, but can defend d6 and c7 (which can be important as white often goes for c5, cxd6, Nb5, Nc4 and Rc1).

Anyway, the differences between each choice of knight move are theoretically rather subtle, as you often find the knight moving back into f6; that said, picking the 'wrong' square gives white the option of changing his plan. In other words, one could probably argue, in some sense, that you don't pick the option that is favorable, but rather eliminate those that are not.

For example, back to the Bayonet Attack, after the main move 9...Nh5, white plays 10.Re1 to meet 10...Nf4 with 11.Bf1, and now 11...f5 runs into 12.Bxf4 and 13.e5. So the main line runs 10...f5 11.Ng5, and black can go for 11...Nf4 here, but it's not clearly favorable to 11...Nf6 (which is in fact the main move; ...Nf4 is considered a serious alternative). That said, 9...Nd7 is considered inaccurate, and white can attempt to highlight this with 10.a4, and simply carry on with his queenside attack (10.Nd2, which transposes to positions reached through 9.Nd2, sort of lets black off the hook, as white had no immediate motivation to move his king's knight, as black is not 'threatening' 10...Nh5)

A theoretical note: the immediate 9.Ne1 and 9.Nd2 were the old main lines as white wanted to stop 9...Nh5; the modern Bayonet Attack argues that white can allow it.


What is this trap in QGD? I recently watched an Eric Rosen video where he showcased a trap in the QGD. I do not remember what the trap was called. Here are the moves.
[FEN ""]

1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 Nbd7 {The trap is this move, because the d5 pawn is not actually free} 5. cxd5 exd5 6. Nxd5 Nxd5! {And White falls for it!} 7. Bxd8 Bb4+! 8. Qd2 {White is forced to give up their queen since that is his only move} Bxd2+ 9. Kxd2 Kxd8 {Black is up a knight, and has a safer king than White, and White’s only compensation is a pawn. Lichess’s Stockfish rates this to be ~-3.}

I don’t remember the name of the trap. If anyone could let me know that would be great. (Bonus points for anyone who can link me the Eric Rosen video!)


FIDE tournament rules: Does a player HAVE to record the opponent's move before making a move? Suppose I play 1. e4 and my opponent plays 1..e5. Do FIDE tournament rules require me to write 1...e5 on my scoresheet before I play the next move 2. Nf3?

No, you don't have to. In rule 8.1 of the Laws of Chess, it says:

  A player may reply to his opponent’s move before recording it, if he so wishes. He must record his previous move before making another.

So your previous move must have been recorded by the time you make the next. You must have recorded at least 1.e4 before you can play 2.Nf3.


Well-annotated books for average players I am looking for well-annotated books as a follow up to my reading Chernev's Logical chess: Move by Move. I have been playing chess on and off, but not quite seriously.

I am also trying to build my chess library - I currently own Chernev's Move by Move, Weeramantry's Best Lessons of a Chess Coach and reading through Silman's The Amateur's Mind.

Additionally, are there any books that cover the psychological aspects of the game?

I would like to take my game to the next level, so I would appreciate your inputs. Thanks!

I'd direct you to NM Dan Heisman's recommended reading list, specifically his Recommended Instructive Game Anthologies section.


Is there a computer program that generates quality chess problems? Is there a chess engine that automatically generates quality chess problems. For example I will input 3 - it produces a mate in 3 problem. But the problem shouldn't be so obvious that one can solve in microseconds.

I don't know if such an engine exists, but there probably might not be one yet and here's why-

It's hard to explain to engines what is "obvious". What might be obvious to you might not even be obvious to me. However, there is some recent research in the area of beauty in chess problems. Even if one takes such factors as "depth appeal", "visual appeal", etc. as outlined in this research, there still remains the fundamental problem of generating chess positions.

Considering the fact that there are at least 10^43 chess positions, it is not yet computationally feasible to generate positions and apply "beauty" analysis to them to see which ones are "quality" problems.

However, we do have endgame tablebases. It could be possible that one could use the already generated 6 piece tablebases and apply the algorithms of the research on them and generate quality problems. However, I do not know if anyone has done that yet.


Is FIDE still using the same logo for world championship final? I remember that this logo was used last championship, why are they still using it? Shouldn't every final have its own logo? Am I missing something?

Are you sure? I don't remember seeing it, and googling I couldn't find a source from 2016 with that logo. Here's the one that I found:


Is there more than 1 solution? In this selfmate puzzle is there more than one solution? I think I found one but I was curious to know if there is more than one.
4N2k/5P2/3p1rP1/2pP4/2p1K1R1/2B1P1N1/6Pp/8 w - - 0 0

Credit: J. C. J. Wainwright, first published in Alain C. White's Theory of Pawn Promotion, 1912

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


Demystifying Seirawan-Kasparov 1983 king and pawn endgame I am currently studying the Tarrasch Defense 1.d4 d5 2.c4 e6 3.Nc3 c5, and naturally I've stumbled upon many Kasparov games as he frequentloy and quite successfully employed this opening throughout his career. In particular, in the game Yasser Seirawan vs Garry Kasparov (1983), a remarkable endgame position transpires:

 [title "Seirawan-Kasparov 1983, position of interest after move 47.f5"]
 [fen "8/8/5p2/p1k2P1p/Pp2P2P/3K4/8/8 b - - 0 1"]
 [startflipped "0"]

 1...Kc6 2.Kc4 Kc7 3.Kd3 Kd7 4.Ke3 Kc6 5.Kd3 Kc5 6.Ke3 b3 7.Kd3 Kb4 8.e5 Ka3 0-1

Kasparov wins this game, but his technique goes very quickly beyond me and I'm struggling to understand the maneuvers that followed, particularly, black starts retreating towards the 7th rank and then returns to c5, and only then advances the b pawn after white has to make a move away from the  its current d3 square. My questions:

Did white miss any drawing chances in this position?
What was the plan underlying black's retreating king march?
Given this starting position, is one already able to recognize a winning pattern for black?

My attempt with this question is to learn more about how to reason about such endgame and to understand how Kasparov composed this (to me counterintuitive) plan.

In this game Kasparov is showing a perfect demonstration of the triangulation technique in order to Zugzwang the white king.

To be in a Zugzwang means, any move loses or more generally, worsens your position, and one cannot simply pass the turn and maintain the position.

In the diagrammed position, the key idea to spot is that white would be in Zugzwang if it was their turn to move. Let's see how by playing the position
assuming it's white's turn again after 47.f5:

 [title "(1) Same position as in the question, but white to move"]
 [fen "8/8/5p2/p1k2P1p/Pp2P2P/3K4/8/8 w - - 0 1"]

 1.Ke3 {only move giving us some resistance} (1.Kc2 Kd4 {e pawn falls and black wins}) (1.e5 fxe5 2.f6 Kd6 {black's in time and wins}) (1.Ke2 Kd4 2.Kf3 b3 {b pawn promotes}) b3 (1...Kc4 2.e5 {and white draws}) 2.Kd3 Kb4 3.e5 Ka3 {last key move, stopping white's king from preventing b2, and black promotes first and with check, which wins trivially.}

Having spotted the winning idea when it's white to move, next comes the question of how to achieve this Zugzwang position?
Essentially, black needs to find a way to pass the turn, that is, intentionally lose a tempo in order to have the same position but it being white's turn. This is called the triangulation technique.

Before unraveling Kasparov's triangulation plan, let's have a typical triangulation exercise:

Triangulation in Kings and pawns endgame:

In the diagrammed position below, black has the opposition as it is white to move. One sign that triangulation might be possible to achieve is to realise that one king has fewer squares than the other one. Here, black has only 2 squares d7,c6 in order to stop the advance of the c pawn and shoulder the white king simultaneously, while its counterpart, the white king, has 3 squares d5,e5,d4. So to pass the turn, the triangulation goes as: 1.Ke5 Kc6 2.Kd4 Kd7 3.Kd5 and mission accomplished: white has the opposition now as it is black to move. The resulting  opposition is winning as black is in Zugzwang: all 4 legal moves Ke7, Ke8, Kd8, Kc8 are losing (convince yourself as an exercise).

Kasparov's triangulation:

Similar to our previous example: black has to achieve the same position but with white to move, so we need to waste a tempo and pass the turn. This immediately calls for a triangulation scheme! Its feasibility here lies again in the fact that white's king has fewer squares than black's. See the diagram below:

where green shows black's triangulation plan, red shows black's threats, and blue shows white's only available squares, since:

anything past the 4th row (e.g. white king chasing the black king) loses to the b pawn promoting,
Kd4 constantly loses to Kd6 (black has opposition and thus, wins the e4 pawn),
and finally descending to the 2nd rank (e.g. 1...Kc2) gives free access to the e5 square for black, which again loses trivially (as white cannot defend both the e4 pawn and stop the b pawn).

Therefore, white only has the c4,e3 squares, i.e. fewer squares than black's king, which means the basic requirement for a successful triangulation is met, and we should be able to reach the desired position with white to move!

Now let's see the plan in action (annotated diagram):

 [title "(3) Kasparov's triangulation and Zugzwang"]
 [fen "8/8/5p2/p1k2P1p/Pp2P2P/3K4/8/8 b - - 0 1"]
 [startflipped "0"]

 1...Kc6 2.Kc4 Kc7 3.Kd3 (3.Kd4 Kd6 {and black has the opposition and wins as Ke5 can no longer be prevented}) Kd7 {the Zugzwang is already achieved: Kc4 leads to Kc6 Kd4 Kd6 black winning, and Ke3 completes black's triangulation as we will see} 4.Ke3 Kc6 5.Kd3 Kc5 {and triangulation completed: same position we started off from but with white to move! Black wins, the Zugzwang situation was discussed in diagram (1).}

Final remarks:

What a beautiful endgame! Don't be discouraged by the difficulty of these endgames, nor misled by the simplified depiction of the triangulation scheme above. Endgames, in particular kings & pawn ones, are known to be notoriously concrete and counterintuitive. Moreover, judging whether a successful triangulation is possible, is often far from being a simple matter. For example, in the above we constantly had to make sure all the other lines for white were indeed losing and that white's best bet lied in dancing along c4-d3-e3, and only then it made sense to compare which king has fewer squares! There's no singular-universally valid rule of thumb that tells us whether a triangulation leading to putting the opponent's king in Zugzwang exists or not. There are only signs, which need to be carefully considered.

The execution of these techniques, and the conversion of such endgames can never be achieved intuitively, one mis-step and all our advantage and efforts are out the window. For instance, in the game as you showed in your diagram, 8...Ka3 is in fact the only move that wins! To improve, focus on expanding your knowledge of endgame techniques (opposition, triangulation, Philidor/Lucena positions, etc), and in practical play, in order to recognise whether a combination exists, like in the Kasparov game, the mindset generally is:

spot an idea (e.g. is it Zugzwang if I pass? like in the above game)
calculate relevant variations (see if technically the found idea is achievable, e.g. in the above: can I achieve a successful triangulation?)
Evaluate the final positions in your calculations (like we did above for all the discussed losing variations)


If a chess board is disturbed, can the game continue? Let's say I'm playing a game that has technically begun (white has moved) and then the board is disturbed: say a minor earthquake shakes the pieces off the table or something.  Clearly no-one has interfered so there is no cheating, but what happens next?

If the moves are logged, can the pieces be returned to their previous positions and the match resumed?  Or must the match be aborted and the board reset?

I'm mostly interested in the international tournament rules but I'm interesting in hearing of 'house rules' as well.

From the FIDE Laws of Chess, article 7.6:

  If, during a game, it is found that any piece has been displaced from its correct square the position 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. The game shall then continue from this reinstated position.

Put into practice:

If the moves are logged, then it's trivial to determine the "last identifiable position" and the game can be resumed as if nothing happened.
If they are not logged (or the two scoresheets differ), the arbiter can attempt to find the "last identifiable position" by asking both players. If they both remember the exact same position, then the game can continue from that position.
If that fails too (because the players don't remember or disagree), there is at least one "last identifiable position" that can always be determined,  the starting position. So yeah, the game is essentially reset in that case.

Article 7.1 applies basically the same rule to the readjustment of the clock, if there is one (with some more wiggle room for the arbiter):

  If an irregularity occurs and the pieces have to be restored to a previous position, the arbiter shall use his best judgement to determine the times to be shown on the chessclock. This includes the right not to change the clock times. He shall also, if necessary, adjust the clock’s move-counter.


How many different knight's tours are there? How many solutions does the Knight’s Tour puzzle have when the knight first moves from square a1, through all squares (on each square once), and return back to a1? Please give some solutions. Also, does the Knight’s Tour have any solutions for starting from any random square?

Wikipedia
quotes several sources for a count of 26,534,728,821,064 for the number
of closed directed tours of the 8x8 board.  As Brian Towers notes
in his answer, that is equivalent to the count of Knight's tours
starting from some given square (such as a1) and ending on the same square.
The same Wikipedia page exhibits several such tours.


Could black have taken the queen here? Could black have taken the queen here?

Note the bishop and the knight

 [FEN "r5k1/1b3Qpp/5b2/p1p1N3/2P2P1P/8/P1N5/K4Rn1 w - - 0 1"]
 [Title "Can black take the queen?"]

No, black could not have taken the queen. Taking the queen would put black's king into check, which is not legal. Black cannot take the knight either because black's king would still be in check.


Is there some resource of non-tactical positions to practice analysing? In point 3 of this answer RemcoGerlich implies that a good way to improve, for a class player, would be to develop the skill of “[taking] any position and [figuring] out what’s going on”.

It seems to me this is the kind of observation that has been made quite often before. Is there any kind of resource that provides a collection of positions for this purpose? Preferably ordered by difficulty and with some annotations to check your own analysis against.

Clearly, there are books about the middlegame but the ones that I know talk about various topics in isolation (providing positions which revolve solely around the topic of that chapter) and not about general analysis. (Not that I would like such a collection of positions to only include middlegame positions but this example comes the closest to what I have in mind.)

I am also not looking for tactical puzzles. There are plenty of books and apps that provide them. In case of a tactical puzzle it’s very clear what’s going on in the position: there’s an immediately winning tactic. (Or sometimes a single drawing move. But mostly it’s clearly one or the other.)

Annotated games could possibly be used for this, but it’s not trivial to select the positions that would be of interest for this without reading the annotations. Also, the strategical themes wouldn’t change so often during a single game so the amount of practice positions derived from an annotated game is quite low relative to the effort required to find them – clearly a selection by a renowned chess teacher would be far superior.

Ideally, I’m looking for a collection of positions that are decidedly not tactical and that have various strategical themes in them so the reader may analyse and evaluate the position, afterwards checking with the provided annotations. They don’t need to have a clear best move, it would be enough to just try and find all important themes and get a good sense of which side is better.

I looked at my library, and opened up a number of books. The old Dvoretsky books really do not do this much, but the "School of Future Champions" and "School of Chess Excellence" series do have many sections that just say "white (or black) to play", and nothing more.

Other Dvoretsky books that do that significantly are "Recognizing Your Opponent's Resources", which has 154 such examples. Also, "Chess Lessons" and "Maneuvering: The Art of Piece Play". That said, all of Dvoretsky's books are quite advanced, and you need to be above 2000 OTB, preferably 2200, to really benefit. His last book, "Chess Tests", was nothing but positions.

A couple of other tough books, but not as tough as Dvoretsky, are the classic "The Best Move" by Hort and Jansa, and "Test Your Chess Skills" by Sarhan Guliev and Logman Guliev. Again, both are a bit advanced, but still OK for a wider range of players.

My recommendation for most players are two outstanding series of books. The Yusupov series "Build up/Boost/Chess Evolution". There are 10 books in the series, and in each one, there is a lesson, and then a series of 12 test exercises for each lesson with just who is to move. The first four books are not simple, but they are accessible to players of a very wide range of OTB ratings. They get harder after that. This series is like having your own former top-10 GM as your teacher.

The other is the Jacob Aagaard series "Grandmaster preparation". There are 6 in this series, and there are many problems within each book. One of these books is even called "Grandmaster Preparation - Calculation".

Start with the first four Yusupov books, and go from there, is my recommendation.

P.S. The Yusupov books cover everything, from opening to tactics, to endgames, to positional play, as you specifically asked about.

P.P.S. NoseKnowsAll mentioned Silman below, and Silman posts a lot of articles he writes on chess.com. While not all are position-related, he does a lot about pawn structures, and other positions. You can find them here (click "More" at the bottom to see more of his articles to find the ones you want).


Gambit openings for black recommendation? I recently started to learn chess, but I play mid to advanced Chinese chess. So to get the most out of transferable skills, I would like to avoid positional/pawn play, but prefer aggressive openings to bring non-pawns into contact very early.

I tried a bit with King's Gambit and Smith-Morra for playing white. What are the aggressive (gambit?) defense lines for black against 1.e4 and 1.d4? Are there early gambits that are easy to reach but hard to decline, even if in theory white's better?

Thanks.

Two gambits that your opponents would likely play into a fair amount, and are defined by move two, are the Latvian Gambit (1.e4 e5 2.Nf3 f5, like a reversed King's Gambit) and the Albin Counter-gambit (1.d4 d5 2.c4 e5). Between the two, the Albin is considered more sound, and even sees top-level games from the likes of Morozevich and Nakamura. The Latvian is generally seen as much shakier. In any case, these two bring the fight to White without delay, and might be the sort of flavor you're looking for.

[White "Latvian"]
[Black "Gambit"]
[fen ""]

1.e4 e5 2.Nf3 f5

and

[White "Albin"]
[Black "Counter-Gambit"]
[fen ""]

1.d4 d5 2.c4 e5


What does the sign of the score represent in chess engines? I am trying to code a small chess engine, but I am confused with what the sign of the score means. This is my current minimax algorithm:

INFINITY = 999999
def minimax(self, depth, color):
    if depth == 0:
        return (1 if color else -1) * self.evaluate()
    if color == WHITE:
        max_value = -INFINITY
        for move in board.generate_moves():
            board.push(move)
            score = minimax(depth - 1, not color)
            board.pop()
            max_value = max(score, max_value)
        return max_value
    else:
        min_value = INFINITY
        for move in board.generate_moves():
            board.push(move)
            score = minimax(depth - 1, not color)
            board.pop()
            min_value = min(score, min_value)
        return min_value

def evaluate(self):
    score = 0
    if board.detect_checkmate():
        return INFINITY
    score += (piece_values[KING] * (piece_count(KING, WHITE) - piece_count(KING, BLACK))
            + piece_values[QUEEN] * (piece_count(QUEEN, WHITE) - piece_count(QUEEN, BLACK))
            + piece_values[ROOK] * (piece_count(ROOK, WHITE) - piece_count(ROOK, BLACK))
            + piece_values[KNIGHT] * (piece_count(KNIGHT, WHITE) - piece_count(KNIGHT, BLACK))
            + piece_values[BISHOP] * (piece_count(BISHOP, WHITE) - piece_count(BISHOP, BLACK))
            + piece_values[PAWN] * (piece_count(PAWN, WHITE) - piece_count(PAWN, BLACK)))
    return score

See, what is important isn't the lousy evaluation function I have, I think it is about the sign the evaluation function returns. I am confused about the colors of the players and the maximizing player and minimizing player. Is it that if the engine is playing black, it is the maximizing player? Or is the white always the maximizing player?

Evaluation sign should be the colour. Your implementation looks correct to me. I compared yours with:

  https://chessprogramming.wikispaces.com/Minimax

What you did is conceptually identical to the pseudocode on the page.


How to set threads number for Stockfish? How to set number of thread parameter for Stockfish?

I read about Stockfish parameters but there is not description how to set it?

http://support.stockfishchess.org/kb/advanced-topics/engine-parameters

Read http://support.stockfishchess.org/kb/advanced-topics/uci-protocol

setoption name Threads value 4


What are White's advantages against the Greco Defense? After the first two moves of the Greco Defense

[fen ""]

1. e4 e5 2. Nf3 Qf6

what should White's agenda be?  I see that the wikibook Chess Opening Theory suggests 3. Bc4, but it doesn't go into detail.  I'm not used to this opening as White, and never play it as Black, so I'm not sure 1) what to aim for in order to undermine Black's early Queen advance, and 2) how to guard against a possible kingside attack.  For instance, should I castle Queenside, or isn't that necessary?

2... Qf6, while not strictly unsound, is definitely an inferior move, not only because it develops the queen prematurely, but also (and more importantly) because it deprives the black king's knight of a very natural square on f6. Don't panic about a possible king-side attack -- black cannot mate with no minor pieces developed. There are a number of reasonable continuations for white:

3. Nc3, a natural and flexible developing move that eyes the d5 square, threatens to chase the queen with gain of time, and doesn't commit to any particular pawn structure.
3. d3, a perfectly valid move, but somewhat passive and has the distinct flaw of locking in the light-square bishop. Unless you strongly prefer to play slow, positional chess, I would develop with 3. Bc4 prior to playing d3 (if at all). If you play d3, the logical plans are either to prepare a central break with c3 and a subsequent d4, or to castle kingside and prepare f4 after re-maneuvering the f3 knight. Which of those plans is preferable depends on your opponent's development, of course.
3. Bc4, versatile and potentially very aggressive, threatening an eventual Ng5 and pressure on f7 after white's d-pawn moves. This is definitely the move I'd favor in a rapid game, and I don't think it's objectively worse than 3. Nc3.

Other moves, such as 3. d4 and 3. c3, are probably sub-optimal. An immediate 3. d4 push is likely to lead to exchanges and a relatively drawish position (and might end up transposing to lines of the Scotch that are not particularly good for white), while 3. c3 is slow and somewhat crude and might allow black to equalize with dynamic piece play.


Can you save white from checkmate? Is white able to recover/win this game after these moves?

And then black takes the bishop:

White resigned after this, what would you do?

First off: I suspect White resigned due to the material disadvantage rather than some immediate mating threat. Having said that, I don't see any reason not to give check on c8 and try to setup some threats here as White, since it seems like Black gets checkmated:

1.Qc8+, Ke7 2.Rb7+, Kf6 3.Qf5+, Kg7 4.Qxf7+, Kh6 5.Qg7#


How can I move quickly in time? I am a slow chess player. I have 3 digits rating in blitz. How I can play fast so that I do not loose on time ?

I think, yesterday, I have answered such a question here.
I am just pasting the answer and adding a few resources to it. You should keep these in your mind.

Smooth Transition: As per other answers, I think you should try 15+0 [Rapid] >> 10+5 >> 10+0 >> 5+5 / 5+3 [Blitz] >> 5+0 >> 3+2 >> 3+0 >> 2+1[Bullet] >> 1+0, in following manner: If you can complete (win/lose) 10 games in a row within the given time then go for the next tier.

One Opening man: Instead of experimenting with different openings, you must stick with a single one and simultaneously have to study it deeply. After studying a line properly, set a target to play first 10 moves within 10 sec. If you follow a single line (eg., 1.d4) for more than 100 games; then you will find that it is quite easy for you to reply not only fast but also accurate. And it will help you significantly in time management.

Pre moving: After "mastering" an opening, try to pre-move [This is crucial in the bullet, not in blitz]. Just make sure to play first 10 moves within 5 seconds!! and you will rock on bullet [at least below 1500 tier].

Pattern Recognition in Middlegame: A simple way to play ultrafast middlegame is pattern recognition (eg., if both King and Queen are in the same diagonal, then try to find your bishop to set a "Royal Fork"). The only way to achieve this is by practicing a lot of puzzles. So, be prepared to try at least 20 puzzles (If possible 50) each day.

Accurate Endgames: "All's well that ends well." So, be focused at your endgame. First, master the checkmate patterns (Staircase mate, smothered mate etc.) and then try the comparatively advance theory (like opposition). If you are already good at endgame, then invite your opponent directly from the opening, by exchanging valuable pieces early in the game.

Here are a few resources you can check:
Beginners training kit at lichess.
Tactics training at Blitz-tactics
Puzzles at lichess
Hope it helps. Good luck.


When should I take on c4? I always encounter such a position:

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
[StartPly "11"]

1. d4 d5 2. Nf3 e6 3. h3 Nf6 4. e3 Be7 5. Bd3 O-O 6. c4 Nbd7 7. c5 c6 8. b4 b6 9. Bd2 a5 10. bxa5 bxa5 11. O-O Ne4 12. Bxe4 dxe4 13. Nh2 Nf6 14. Qe1 a4 15. Bb4 Ba6 16. Nc3 Bxf1 17. Nxf1 Rb8 18. a3 Ra8 19. Qd1 Qc7 20. Nxa4 Rfd8 21. Nb6 Ra7 22. Nd2 Nd5 23. Nxe4 Nxb4 24. axb4 Rxa1 25. Qxa1 f5 26. Nc3 Bf6 27. Qa2 Kf7 28. g3 g6 29. Kg2 Qb7 30. Ne2 Qc7 31. Nf4 Rb8 32. Qxe6+ Kg7 33. g4 fxg4 34. hxg4 Bxd4 35. exd4 Qxf4 36. Qd7+ Kh6 37. f3 Qd2+ 38. Kg3 Qxb4 39. Kf4 Rf8+ 40. Kg3 Qe1+ 41. Kg2 Qe2+ 42. Kg1 Rxf3 43. Qxc6 Rf1#

Stockfish recommends 6.. dxc4, while I played Nbd7. Why makes dxc4 better?

It is really a matter of taste over "better".  I like the tempo gain that dxc4 gives.  Usually the pawn is on c4 before Bf1-d3, but when Bf1 develops, as in your game, it loses time capturing on c4.  Additionally, the Bishop sucks on c4 and will likely move yet again.
Black will have time to play c5 with a nice game.


Bug in Stockfish/Suggesting bad move Why does Stockfish suggest this move in this position for white? It is a clear losing position if the king moves that way, as supposed to a draw if the king chooses f7 instead...

This is a real game that ended up this way.

I can't be sure, but I suspect Stockfish just hasn't completed its move or flushed the current move to your UI. Or the UI you are using isn't giving all the information.

My Stockfish (6) gives '1. Kf7', unsurprisingly.


What are the common themes in the Catalan? I have looked over some of the main lines of the Catalan in MCO-15 and feel pretty lost as to what's going on in them. What are some of the key positions and goals for either side? Or is the opening just too tactical to have any real unifying themes?

The Catalan Opening (E01-E09)

rnbqkb1r/ppp2ppp/4pn2/3p4/2PP4/6P1/PP2PPBP/RNBQK1NR w KQkq - 0 4

I have played the Catalan for something like 25 years, and to me the big secret explaining the opening's popularity is the following: You can expect a massive score against weaker players.

The key strategic factors in a successful Catalan are:

1) You achieve control/dominance over all four central squares, something rarely seen in other openings. (By the way this explains why the Catalan set-up isn't so effective with a black bishop on f5; white has too little control over e4.)

2) Long-term pressure against black's queenside, in part exerted by the bishop on the diagonal. In the end something is going to break.

These factors make it possible to turn up unprepared for a game Sunday morning during a weekend tournament and have a winning position before the first cup of coffee. In other words, great opening!

For books that focus on philosophy and not too much on concrete moves I can recommend the series How Wojo won.


What is the book containing this puzzle with an unexpected answer? (To best of my recollection) In the book a diagram was given with the side note something like X vs Y, 1920 or 1930 Morocco or some other place with the question "what did black do?"

After some careful examination it seemed like there is a win for black etc., but when looking up the answer at the end of the book:

  A: If you said (insert combination here) black wins, you are wrong, as in actual game (black missed the winning combination) black resigned!

Anyone can suggest the book that contains this puzzle and answer?

Well, here's a link that contains the game, probably.  I'd guess it's example #1.  This may give you more information for your research.


Plans for White and Black in the Queen's Gambit Accepted I often play this variation of the Queen's Gambit Accepted:

[fen ""]

1. d4 d5 2. c4 dxc4 3. Nf3 Nf6 4. e3 e6 5. Bxc4 a6 6. O-O c5 7. dxc5 Qxd1 8. Rxd1 Bxc5 9. a3 b5 10. Be2 Bb7 11. b4 Be7 12. Bb2 Nbd7 13. Nc3 O-O 14. Rac1

My question is, what are the plans for White & Black? I get a bit lost when I reach this position.

Also, any other tips on my opening would be most appreciated

I'm not an expert on this line, but one idea from "Study chess with Matthew Sadler" stuck in my mind: To play against the b7-bishop with f3 and e4. So that might be an objective for white. For black this is probably harder to archive, because the Nc3 is ready to jump into d5.

But this Nc3 instead of Nd2 gives black a different target: The square c4. Say after 14…Rc8 15.Nd4 Ne5 makes some sense, to jump into c4 and possibly acquire the bishop pair. Though after 16.Nb3 this doesn't yet work tactically, because of 16…Nc4 17.Bxc4 Rxc4 18.Na5 Rc7 19.Nxb5 …

So maybe 14…Rc8 15.Nd4 Nb6 is better, because on b6 the knight will be more stable. Then 16. Nb3 and possibly Nfd5 with the idea to exchange the Nc3 and go Bb7-d5-c4.

This was a bit of a stream of consciousness, but I'll try to sum up:

Playing f3 and e4 to blunt the bishop b7 is an idea.
The squares c5,a5 and c4,a4 are targets for the pieces. Especially the knights can be very annoying if they reach such a square.
There is always the idea of playing a4/a5 to try and liquidate the whole queenside, especially if there is still a rook on the a-file.
This might look like a very calm position, but with so many pieces still on the board, you should definitely look out for tactical possibilities.
If you don't find anything better to do, you can move your king closer to the centre: It is always possible, that some mass exchanges leave you in an endgame, where the king centralisation will be key.


What is the solution to single-check chess? Single-check chess is a variant where the first person to give check wins. There is a website that claims it has been solved, with white winning in four moves; however, I cannot find the moves anywhere.

If you trust Stockfish's evaluation on lichess.org, using the "three check" variant where both sides already have two checks, White wins in 5 moves with 1. e4, 1. e3, 1. Nc3, or 1. Na3, and loses otherwise.