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Humans use:

  • Pawn = 1
  • Knight = 3
  • Bishop = 3
  • Rook = 5
  • Queen = 9.5
  • Bishop pair = +0.5

But I would like to know what relative point values do engines use (preferably strong engines, like Stockfish, Houdini, Rybka, Komodo, ...).

If the point value that the engine assign to the pieces depends on the position of the pieces on the board (for example a White Knight on a1 is only worth 2.6 but on e5 it's worth 3.4), than I would like to know the average point values of the pieces.

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3 Answers 3

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Rybka/Komodo/Houdini are not open source and their values aren't readily available, but the current strongest conventional engine, Stockfish, uses these values (lines 194-198):

PawnValueMg = 126, PawnValueEg = 208,

KnightValueMg = 781, KnightValueEg = 854,

BishopValueMg = 825, BishopValueEg = 915,

RookValueMg = 1276, RookValueEg = 1380,

QueenValueMg = 2538, QueenValueEg = 2682,

The "Mg" column is the value used during the opening and middlegame, and the "Eg" column is for the endgame. In units where the value of a pawn is 1:

Middlegame: Knight = 6.198; Bishop = 6.548; Rook = 10.127; Queen = 20.143

Endgame: Knight = 4.106; Bishop = 4.399; Rook = 6.635; Queen = 12.894

As you might guess, these numbers are empirically tuned.

Edit: Just for the record, this answer is old, because these days all the strongest engines use neural network-based eval, and there is no longer "point values".

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These are the values used by Crafty - one of the best open source chess engines.

#  define PAWN_VALUE                             100
#  define KNIGHT_VALUE                           325
#  define BISHOP_VALUE                           325
#  define ROOK_VALUE                             500
#  define QUEEN_VALUE                           1050
#  define KING_VALUE                           40000

If you can follow the C code, then you can dig deeper by looking at the the source files that are available.

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I have the strong commercial chess engine Shredder Classic 4. When I open up its engine options I get the default strengths of the pieces. Without reading the documentation of this engine it seems that Shredder starts off with the traditional piece values of queen = 9.5 pts, rook = 5 pts and so on. Then there are optional sliders where I could make any type of piece worth more or less. Interestingly the default value for a "bishop pair" can also be increased or decreased by the player.

This seems to be about the best that I can do with Shredder to try to give an "average" strength of piece valuations.

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