Frank-Walter

Frank-Walter is a java-based winboard/xboard chess engine written by Laurens Winkelhagen.

Frank-Walter 2.2.0

Frank-Walter is a java chess engine that requires java 8 or higher to work. Java can be downloaded from https://www.java.com/. The engine can be started with the command java -jar frankwalter.jar <options> where <options> are optional commandline parameters.

Currently the following commandline parameters are available

• -debug (no arguments, causes logging to be stored in a file called debug.log in the current working directory)
• -tt <magnitude> (where <magnitude> is a number between 17 and 26 inclusive denoting 1MB up to 1GB memory allocation for the transposition table. The default is 24, which means 256MB)
• -tb <tablebases filepath> (here <tablebases filepath> is the Syzygy-tablebases directory. It is also possible to configure this in xboard)

• Bitboard legal move generator using magic bitboards and kindergarten bitboards
• Principle Variation Search with aspiration window.
• Mostly Piece-Square value based evaluation (tuned using texels tuning method)
• Easy to understand opening-book format (Beowulf format)
• Syzygy Tablebases support (dependant on platform: I have only compiled the native code for linux)

This java program makes use of Syzygy Tablebases via the Java Syzygy-Bridge: a modification of the Fathom c/c++ program, in combination with a java library that can use this native library. Due to practical constraints, there is only a linux version of the JSyzygy library available. In order to use Syzygy tablebases, the file libJSyzygy.so should be placed next to the frankwalter.jar file, or in the java library directory. The Syzygy tablebases themselves can be generated locally, or downloaded from the internet.

Frank-Walter would not have been complete or even possible without the inspiration and material provided by the following people:

• Working with magic bitboards and kindergarten bitboards it is hard not to acknowledge Gerd Isenberg, Pradu Kannan en Lasse Hansen.
• The openingbook format is the Beowulf-format. Principle author Colin Frayn also provided the basic book, used with permission.
• Texels Tuning Method was developed by Peter Österlund, I have made use of the positions provided by the authors of Zurichess (quiet-labeled.epd).
• Syzygy Tablebases were developed by Ronald de Man. Basil00 made a c/c++ library for easy integration in c/c++ projects. I’ve taken the fork of Jon Dart and integrated in my Java program via JNI.
• In general, the people on TalkChess forums and behind the Chessprogramming.org wiki have been great sources of ideas and knowledge.
• Finally, this text would not be here without Ron Murawski - thank you for hosting Frank-Walter!