The Baron is a strong chess engine written by Richard Pijl.

July 7th 2015: Release of Version 3.29 (Dated Feb 26th 2012)

  • The bitbases mentioned in the configuration file is the own Baron format, which I replaced already with the Syzygy ones in newer versions of the Baron. These bitbases are therefore not available
  • No native books available for the Baron.
  • Native CTG support is there, but it mainly responds on annotation symbols in the book (!!, ! and ?). As the scoring method of Chessbase has not been described yet, there will be differences in moves that will be played by ctg-books based on game statistics between the Baron and Chessbase GUIs.
  • The Baron supports both UCI2 and Winboard2 and can also be used from the console (using winboard style commands).

Bugs solved:

  • 50-move draw bug fixed
  • SMP bug fixed that caused aborting searching plies, resulting in the display of erroneous drawscores
  • A buffer overflow in the internal epd test suite code is fixed
  • FRC/Chess960 support is fixed


  • New defaults for several parameters are chosen, most of them based on the work by Rodolfo Leoni. These are reflected
    by the attached sample baron.ini file. Among those that are impacted:
  • This makes the learning file incompatible with previous versions. The name is changed to ‘baron.plf’
  • The length of the zobrist key in the learning file is increased from 64 to 128 bits
  • The two learning options are now replaced by a single new one: learning. It can be turned on or off.
  • Redesigned the Position Learning code as part of the ongoing rewrite.
  • Rewritten Hashkey handling in the hashtable. More bits are now available to prevent hashkey collissions
    • nullbase (now 10)
    • nullprogress (now 8)
    • singmargin (still 100, but internally the values were changed, comparable to the old 40)
    • splitdepth (now 12)
  • The recommendation is still to leave everything commented out unless you know what you’re doing. Default may change in a future release again
  • Changed scoring weights of the Baron’s own book format. Not relevant for other book formats
  • Multi-PV mode is more stable (i.e. moves remain in the same order unless the score changes)