Ronja

An XBoard/WinBoard chess engine written in Java.

System Requirements

Ronja is a chess engine. It provides only a simple, character based user interface. It is highly recommended that you run it from a chess GUI like XBoard/WinBoard or Arena.

Ronja runs on these platforms:

• Linux on x86_64 and arm64
• macOS on x86_64 and arm64
• Windows on x86_64 and arm64

Running a version older than 0.10.0? See Old Versions.

Installation

Download the archive for your platform from the GitHub releases page. The archive name ends with your operating system and architecture, for example ronja-0.10.0-windows-x86_64.zip or ronja-0.10.0-macos-arm64.tar.gz. Unpack it into a directory of your choice. Let's call this directory <ronja_home>.

XBoard

Find the XBoard resource file .xboardrc in your home directory. Now find the option -firstChessProgramNames in this file. Add a line like the following in the list of chess programs:

"Ronja" -fcp ./ronja -fd <ronja_home>

WinBoard

Find your WinBoard .ini file. It will be located somewhere in your home directory in AppData/Roaming. Now find the option /firstChessProgramNames in this file. Add a line like the following in the list of chess programs:

"Ronja" -fcp ronja.bat -fd <ronja_home>

Arena

In Arena, you should go to Engines | Install New Engine... In the dialog that appears, navigate to <ronja_home> and select ronja.bat. In the next dialog, set the type of the engine to Winboard. That's it!

Log Files

Ronja writes its log file ronja.log to a folder of your own, so that <ronja_home> can be a folder you cannot write to, such as /usr/local:

• Linux and macOS: ~/.local/state/ronja, or $XDG_STATE_HOME/ronja if you have set XDG_STATE_HOME
• Windows: %LOCALAPPDATA%\Ronja

If you turn on the game log in ronja.properties, Ronja writes it to the same folder. When you start Ronja in a terminal, it prints the folder on a line that starts with # Log folder.

Description

Ronja is written entirely in Java, and has its own opening book. It implements a few of the commonly seen features of chess engines:

• Iterative deepening
• Alpha-beta pruning
• Move ordering

Ronja is designed in an object-oriented way, with classes representing positions, and other entities. This makes the engine rather slow, and so may be changed in the future.