Endgame Bitbases

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Endgame Bitbases,
are compact endgame tablebases with game theoretical values of one or two bits per position stored. They are sufficient for various material configurations to reside inside RAM for short probing access time, intended to use deep inside the search. The boolean or four valued ranges are either {won, not_won} or {won, draw, loss, invalid}. While WDL information is sufficient to guide the search into won positions, it lacks any sense of progress in won positions. Therefor, programs either probe full tablebases at the root to reveal the number of moves until conversion or mate, or combine WDL-scores with heuristic evaluation scores, considering material, ply-distance to the root, pawn closeness to promotion, distance of pieces to opponent king, etc.. Endgame Bitbases were described in 1999 by Ernst A. Heinz in Knowledgeable Encoding and Querying of Endgame Databases, as applied with 4-men in DarkThought [1].

Bitbase Implementations

See also


Forum Posts


Wu/Beal predates Koistinen by Guy Haworth, CCC, December 04, 2001



2015 ...

External Links


  1. Ernst A. Heinz (1999). Knowledgeable Encoding and Querying of Endgame Databases. ICCA Journal, Vol. 22, No. 2, ps
  2. Gaviota TBs [, bitbase-like interface] by Miguel A. Ballicora, CCC, February 22, 2010
  3. Generating egtbs ICGAJ by Tony Werten, CCC, December 04, 2001, with reference to Computing endgames with few men by Urban Koistinen
  4. Computing endgames with few men by Urban Koistinen
  5. Ren Wu, Don Beal (2001). Fast, Memory-efficient Retrograde Algorithms. ICGA Journal, Vol. 24, No. 3
  6. kervinck/pfkpk · GitHub
  7. Scorpio 6men EGBB Now available by Joshua Shriver, CCC, January 14, 2014
  8. Yet another KPK endgame table generator: pfkpk by Marcel van Kervinck, CCC, September 05, 2015

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