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

Senpai 2.0

Fabien Letouzey has just released Senpai 2.0. This is mostly a complete rewrite. He’s made extensive changes and added automated tuning of evaluation parameters. You can find out more on the Senpai page.

New Version of The Baron

Richard Pijl has kindly released his latest version of The Baron (3.41). You can find out more, and download it here.

Linux Binaries for Maverick 1.5

Thanks to Antonio Arias we now have Linux binaries included with the main distribution of Maverick. You can download them here.

Maverick 1.5 (Leiden WCCC 2015) Released

I’m happy to announce the release of Maverick 1.5. This is close to the version which competed in the 2015 World Computer Chess Championship in Leiden. I’d estimate that it’s only about +50 ELO better than version 1.o (based on self play). I’m about to embark on a rewrite of the evaluation function so I thought it a worthwhile launch.

The main changes are:

  • Tweaks to the piece square tables (especially pawns)
  • Added endgame knowledge
  • Less selectivity
  • Fixed a quiescent search bug which unnecessarily research some moves

You can download it below or from the Download Page. I’ve only included a 32 bit and 64 bit version which should work on most systems. If anyone would like to create a Linux / Apple Mac compile then I’d be happy to include it in with this version. The source is available here

Pictures from Leiden 2015

New Engine – The Baron

I’m delighted to host another new engine at The Baron recently played at the WCCC in Leiden. It was operated by Richard’s delightful daughter Tessa. I’m not sure of the exact playing strength of The Baron but it’s certainly strong. It’s a full feature engine with SMP support and a comprehensive evaluation function. This version dates back to February 2012.  You can find out more on The Baron’s own page.


World Computer Chess Championship 2015

This week I’m in Leiden for the World Computer Chess Championships. I’ll try to blog about it. Here’s a quick pre-tournament video:

You can see Maverick’s screen and a video link here (maximum of 50 people):