Dirty, EveAnn and Caligula are Windows Winboard compatible chess engines. They are console programs, to use them you need a graphical interface (GUI). The most popular are Winboard, Scid, Arena, Cutechess . . . you can find them easily. Also there are lot of tutorials to install the apps and the engines.
Dirty is a Winboard compatible Chess Engine written by Pradu Kannan (Buzz), Fonzy Bluemers and Andrés Valverde (earlier versions) . Later versions are maintained by Fonzy. It is quite strong. Latest version freely downloadable is :
( 3.023 CCRL . April 27, 2025 )
Read the zipped README file for more info.
Older versions:
Dirty Duna ( 3.012 ELO CCRL )
Dirty Cucumber (2.941 ELO CCRL)
EveAnn is a small Winboard chess engine written by Andrés Valverde. From version 4.0 it uses an evaluation network (NN) built with Cerebrum 2.0 library by David Carteau. The network is embedded in the EXE file, you can disable it in your GUI config or simply deleting/renaming the file CEREBRUM.DLL
( New NN. Search tweak, some bugs fixed
around +20 ELO April 2, 2026 )
Read the zipped README file for more info.
Older versions:
EveAnn 3.7 ( Some bugs fixed. ~3.232 ELO CCRL January 18, 2026 )
EveAnn 3.6 ( Some bugs fixed. ~3.232 ELO CCRL October 15, 2025 )
EveAnn 3.5 ( Some bugs fixed. ~3.221 ELO CCRL October 9, 2025 )
EveAnn 3.4 (Some bugs fixed. Some search tweaks, ~3.207 ELO CCRL aprox. June 13, 2025 )
EveAnn 3.2 (Some bugs fixed. around 3.150 ELO CCRL . 01/05/2025 changes in readme.txt inside the package. Only Windows 64-bit available)
EveAnn 3.1 (around 3.140 ELO CCRL . 26/04/2025 changes in readme.txt inside the package. Only Windows 64-bit available)
EveAnn 3.0 x64 (3.107 ELO CCRL . 11/01/2025 changes in readme.txt inside the package)
EveAnn 3.0 x32 (In case the 64-bit version is not running in your PC.)
EveAnn 2.2 (bug-fix 3.037 ELO CCRL)
EveAnn 2.1 (3.035 ELO CCRL)
EveAnn 2.0 (2.850 ELO CCRL aprox)
EveAnn 1.73 (HCE 2.345 ELO CCRL)
EveAnn 1.71 (2.300 ELO CCRL)
Caligula is a Winboard chess engine written by Pedro Castro taken TSCP ( (c) Tom Kerrigan) as a base, but adding lot of features and making it a 2.700 ELO CCRL engine.
From version 2.0 I have implemented David Carteau's Cerebrum library , as well as other minor changes. The plan is to train bigger and better networks as the library is improved. Current network is trained with Cerebrum 2.0 (net version 2.0.1 included). For version 4.0 I have received the unvaluable help -again- of David Carteau, thanks a lot ! .
You can download and use it completely for free :
( ~3300 ELO CCRL March 12, 2026 )
Jim Ablett's compiles for Windows and Linux included. Thanks!
Read the zipped README file for more info.
Older versions:
Caligula 6.0 (3270 ELO CCRL)
Caligula 5.0 (3226 ELO CCRL)
Caligula 4.0 (3180 ELO CCRL)
Caligula 3.1 (3140 ELO CCRL)
Caligula 3.0 (3085 ELO CCRL)
Caligula 2.0 (2985 ELO CCRL)
Also even older versions and history about the engine can be found at Pedro's home site
Feel free to contact me at andres(dot)valverde(dot)toresano@gmail(dot)com