Questions tagged [evaluation]

The evaluation of a given position

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6
votes
2answers
224 views

What do chess engine evaluation scores (+1.3, -3.2) really mean?

I know that chess engine evaluations like +1.3 intuitively mean that White is evaluated to have an advantage equivalent to 1.3 pawns of material, or that -3.2 means that Black is evaluated to have an ...
12
votes
1answer
1k views

Does blitz change the relative value of position vs material?

The way I see it, true gambits trade material for position, which in turn could give you opportunities to regain more material. However, in blitz play, you are less likely to notice those ...
4
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2answers
190 views

Techniques used for Stockfish engine selectivity

Example puzzle (I'm sure there are numerous that fit this bill): [FEN "rnbq3r/pppp4/3b1pkp/5p2/2BP4/4P3/PPP2PPP/RN1QK2R w KQ - 0 1"] [Site "Earth"] [White ""] 1. Qh5+ ...
10
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3answers
3k views

Why is this seemingly quiet and normal position actually -3?

rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1 [Event "Casual Blitz game"] [Site "https://lichess.org/GETmjlLj"] [Date "2021.08.15"] [White "WMArsyHuda&...
3
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0answers
113 views

How do you evaluate this position?

rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1 [Date "2021.08.14"] [Result "0-1"] [UTCDate "2021.08.14"] [UTCTime "22:01:55"] [...
1
vote
1answer
98 views

Detailed Stockfish Evaluation Function

Stockfish contains the nice 'eval' command that prints out the detailed score of its static evaluation function. It regards Mobility, Material, Bishop, Rooks, etc. However, I was wondering if there ...
9
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2answers
2k views

Why is h4 much better than h3?

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1 [Event "Rated Rapid game"] [Date "2021.08.09"] [Result "0-1"] [Variant "Standard"] [TimeControl &...
5
votes
2answers
282 views

Examples where top engines in a tournament match diverge in evaluation

I'd like to know about computer games of some recent tournaments where two top engines diverge in evaluation of a position, in the sense that both think are winning the game (or both losing). I saw ...
9
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6answers
4k views

Why is 11. .. h6 such a bad move?

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1 [Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [...
3
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2answers
165 views

Can this '+3.9' advantage be converted to a win?

I reached this endgame, which Stockfish 10+ evaluates as +3.9, but failed to convert it to a win. I feel that it may be a draw after all. Is that the case? [Title "White to move"] [FEN "...
1
vote
1answer
46 views

How to score a certain move in a PGN, for how well opening theory is followed

I am making a bot that plays opening moves from a PGN. When the player reaches a position out of PGN, I want to give a score to the player how well he followed the PGN. What kind of statistics can I ...
13
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2answers
1k views

Is there an engine evaluation technique that factors in 'time'?

An interesting game played out between Wesley So and Levon Aronion1: [title "Wesley So vs Levon Aronian"] [fen "rn4k1/p2bP1b1/2q5/1pp2p1Q/2p5/8/PP3PPP/3R1RK1 w - - 0 1"] So was in ...
19
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2answers
5k views

Is this a draw despite the Stockfish evaluation of −5?

I reached this position as Black: [Title "Black to move"] [FEN "8/8/8/3q4/6kp/7R/6P1/6K1 b - - 3 46"] And I felt that I cannot make any progress and so it feels like a draw. ...
0
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2answers
201 views

Why are lots of different moves usually considered equivalent in the opening, but not in the middlegame?

When you go to websites like chess.com and analyze your games, you'll notice that most of the first moves are marked as being "book moves"—which I assume are considered equivalent to each ...
5
votes
1answer
2k views

Why is this position considered to give white a significant advantage?

In this position, black's king is safe, has a secure queenside pawn structure, and has taken out white's left pawns and is up 2 points of material. Despite this, lichess evaluates this position at +3....
7
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3answers
1k views

Why is this "slow move" with the king a good move?

rn1qkb1r/1p3pnp/p1p1p1p1/3pP3/3P2P1/2NBBQ1P/PPP2P2/2KR3R w kq - 0 13 Stockfish (depth 30) says the best move is Kb1 with +1.5 evaluation. I'm having trouble to understand why. The a2 pawn is not ...
1
vote
0answers
149 views

Contempt factor [closed]

I have a question concerning the contempt factor of a chess engine, that i am writing, and thought that this forum would be the best one to ask it in. The contempt factor is a way of deincentivizing ...
6
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2answers
1k views

How come it's actually Black with the advantage here?

I was analyzing a recent game of mine, and I noticed something interesting. After I blundered back a bishop on move 16, the evaluation was -3.4, which is still strongly winning for Black. [White "...
8
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3answers
555 views

Big changes in engine's evaluation after considerable time

I hope this question hasn't been asked before. I am looking for some examples where, say, the latest Stockfish or Komodo engine (or possibly some of the top NN engines) evaluates a position as plus or ...
9
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3answers
2k views

Why is it a mistake to capture the forked rook?

In a recent game, I forked a queen and rook with a knight. After seeing no immediate threats from 8. Qf4 I immediately captured with 8. ...Nxb3. Apparently this was quite a mistake (a 213 centipawn ...
4
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2answers
344 views

Which open source chess engine has the most positional understanding?

Most open source chess engines with hand-tuned evaluations are known for their innovations on search (Fruit, Stockfish). I was inspired by HIARCS' generally more human-like play and the fact that ...
2
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1answer
202 views

The best move in this Crazyhouse position according to Stockfish

I just played my first few games of Crazyhouse, and I really don't understand it. At one point I had this position. [Title "White to move"] [FEN "r2q1rk1/pbb2pp1/n1p1p2p/1p1nP3/2pPN3/...
3
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3answers
1k views

Stockfish Evaluations

I've been getting Stockfish to analyse lines of the KID, and the evaluation gives a score of around +1.5: White has a big advantage. How come this is true, when the KID is a playable(and good) opening?...
1
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2answers
1k views

Lichess endgame evaluation

Why is it that Lichess, and other engines for that matter, give a non-zero evaluation score on an endgame position that should be either a draw or a win for one of the sides (given perfect play)? For ...
3
votes
1answer
190 views

CNN autoencoder for feature extraction for a chess position

I'm currently building a chess engine in my free time while entering my second year of my master's studies in computer science. For a class we need to perform a litterature survey of a topic and ...
28
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4answers
7k views

Should a chess engine be aware of opposite-side castling?

I often hear chess experts and chess articles say that when opposite side castling occurs on the board that it is important to launch an attack on the enemy player as fast as possible. Up to the point ...
3
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1answer
1k views

Deducing brilliant sacrifices

Is it possible to deduce brilliant sacrifices by analyzing a match's PGN along with the corresponding evaluation score after each move? If not, what other non-visual information would be needed to be ...
2
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0answers
127 views

Scid vs PC Score Graph

Is it possible to modify the source code to change the display of the score graph so that you are always at the bottom? Currently, the player playing White is always at the bottom.
3
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2answers
334 views

How to get static evaluation from Stockfish in case that a king is in check?

I am working on a program that should recognize the difference between human and computer players. For this purpose, I need some parameters. A part of them would be the individual values of the static ...
4
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1answer
119 views

Trapped Rooks: Does Stockfish penalize more if the king can't castle temporarily?

In this talkchess thread, they discuss trapped rooks and castling rights. In post #5, user @Lyudmil Tsvetkov posted: I would give at least some 10-15cps for temporary prevention of castling. Here is ...
1
vote
1answer
145 views

ELO change of engine from pure material to very good evaluation

I am currently rewriting a chess engine with a friend. We decided to first work on the search and only later if the search works really well, we will do some very good evaluation. The engine itself ...
2
votes
1answer
84 views

Engine is evaluating the same position at the same depth with different score

My engine is evaluating the same position at the same depth with a different score inside the search tree, is that normal? [Title "depth 1 ply 3 alfa -20 beta -15 score -15 (1.Na3 a5 2.Nh3)"] [FEN ...
5
votes
1answer
174 views

Move evaluation on armageddon games

I am wondering if there is a Stockfish-like evaluation of moves that could take in account armageddon rules, the rules being that you lose if you draw. I would imagine a strategy of just trading ...
3
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2answers
693 views

Can someone explain the positional advantages for white?

[FEN "3r1rk1/7p/bq2ppp1/p1R5/Pp2P2P/4QB2/1P3PP1/3R2K1 w - - 0 1"] As far I can see, Black’s bishop has more scope than the white one, White has some isolated pawns, and the Black pawns rule the 5th ...
0
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1answer
646 views

Mate-in-10 that Stockfish missed!

Stockfish 10+ at depth 19 evaluated this position as a draw: [Title "White to play and mate in 10"] [FEN "r1b2r2/5pk1/pq2p3/1p5Q/3p1P2/P2Rn1NP/1P4P1/7K w - - 0 28"] However, it is actually checkmate ...
3
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2answers
172 views

Discovered attack in quiescent search

I'm implementing quiescent search in my chess engine, although just capturing moves have been generated. In the below position, at 1 ply, the white queen captures the pawn, but the quiescent search ...
30
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4answers
5k views

Why does Stockfish undervalue pawns when compared to the classical "a piece is worth three pawns" approach?

I was taking a look at values engines give to pawns and piece and was quite shocked by Stockfish values for middlegame (Mg): PawnValueMg = 128 KnightValueMg = 721 ~ 5.6 pawns BishopValueMg = 825 ~ ...
9
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9answers
7k views

Is chess a zero sum game?

"Chess is a zero sum game" is a claim you see often, even on this forum. Game theorists will tell you that it is just obvious. Either the game is a draw, nobody wins or loses, or one side wins and ...
6
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1answer
236 views

Looking for an opening that had been wrongly evaluated for years

I'm looking for an opening I saw in a book (not a chess book). The opening was about 10 moves long, and the author stated that the evaluation after the last move shown had been considered for many ...
14
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2answers
3k views

How do chess engines decide which best line to play when the game outcome is within their horizon?

Inspired by the Hot Network Question "In this puzzle, why does white play dxe5?", when a chess engine is in a position that it can definitively call lost, drawn, or won, what policy is used to decide ...
10
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3answers
3k views

Why does Stockfish suggest capturing a bishop in this position when my opponent can fork my king and rook?

The position in question is: [FEN ""] [StartPly "13"] 1. d4 c5 2. Nf3 cxd4 3. Nxd4 Nc6 4. Nc3 e5 5. Ndb5 Bb4 6. Bg5 Bxc3+ 7. bxc3 Qa5 8. Qd5 Nge7 9. Nd6+ Kf8 10. Qxf7# 1-0 It's black turn and the ...
2
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5answers
2k views

How can I use stockfish to find good moves, instead of just bad moves?

After playing on lichess.org I have been reviewing my games as follows: Ask for a computer evaluation (Stockfish) Look at the graph and investigate any wild swings in computer analysis Try to ...
2
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4answers
2k views

Queenless Imbalanced Middlegame

I was analyzing the following position for one of the correspondence games that I am playing. In the position, white is up 2 pawns and with my limited understanding, I can't see any real compensation ...
7
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3answers
3k views

Stockfish: What is the maximum (minimum) centipawn score that a position might be evaluated at?

With the exception of checkmate and mate-in-x positions, what is the highest centipawn score that a chess position might obtain upon Stockfish evaluation? This is a practical question because there ...
9
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3answers
853 views

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 ...
2
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1answer
198 views

What is the highest mobility score of a board without a checkmate, stalemate, or draw?

I consider the mobility score of a board to be the number of legal moves one player could make less the number of legal moves the other player could make. 8/7k/2Q2K2/8/6b1/8/8/8 w - - 0 1 Using the ...
4
votes
4answers
937 views

Help with game phase identification

I'm working on a chess AI for a school project and I am looking into ways to identify the current phase of a board, meaning the opening, middlegame, and endgame. I have seen an article explaining ...
2
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1answer
151 views

Can engines use the current pawn structure to refine its search/eval?

As I understand it, engines use so-called "bitboards" to generate the current position & possible moves. I'm wondering if any engine uses the pawn bitboard to refine its search and eval. To ...
2
votes
3answers
2k views

Chess evaluation function

I am trying to write a program to learn how to play chess. I have heard of programs that you can enter in a set of weights for certain parameters such as rook value, queen value and bishop mobility. ...
4
votes
3answers
980 views

What is the weakest file on the board?

If f2 and f7 are the weakest squares on the board, if the f-file the weakest file on the board? For example, other than attacking f2 and f7, is there a theoretical advantage in dominating the f-file?