New Version of The Baron (3.44)

Richard has released a new version of The Baron. This version cleans up some Syzygy bugs and fine-tunes the engine. He estimates the strength increase is +20 to +50 ELO.

Find out more here:

The Baron 3.44

New Version of The Baron (v3.43) plus The Baron’s Polyglot Opening Book

Richard Pijl has been kind enough to released The Baron 3.43. This is almost identical to the version that played in the 2018 WCCC. Here are Richard’s release notes:

Changes since 3.42:

Bugs solved:

  • Pin detection in evaluation only detected close pins.
  • Handle spaces in the syzygy path
  • Slightly more restrictive in playing easy moves
  • Fixed singular extensions bug
  • Increased search stack size


  • Detecting pins to the queen
  • Evaluation tuning
  • Better use of time, especially on short time controls
  • More selective in quiescence
  • Reduced aspiration window

Changes since 3.41:

Bugs solved:

  • UCI mode possible from the command prompt
  • Handling missing dtz files correctly (I hope)
  • Show Refutations is disabled as I did not have the time yet to look at it.


  • Changed scoring on TB hits
  • Keep probing TB during search on reaching TB positions
  • Added Syzygy path option to UCI
  • Ported to Raspberry Pi
  • Full functionality available in native Linux version
  • Refactoring of several classes

You can download it here. There is also The Baron’s opening book (in Polyglot format).

New Version of The Baron

Richard Pijl has just released another version of The Baron (v3.42). This will be the last version for this code base. Find out more, and download here