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To play Rival on Android, please visit the Android Market on your mobile device and search for Rival Chess or scan the 2D Barcode below with your phone.

For Android devices without access to the Android Market, the APK can be downloaded directly from this link.


The UCI Protocol is a method for chess engines to talk to chess GUIs (user interfaces), providing standard commands that the GUI may send to the engine (such as a request to make a move) and a standard fashion in which the engine can respond to the GUI, when, for example it is ready to make a move.

The Java engine used by Rival for Android can be downloaded as a standalone UCI engine which can either be accessed via the command line or, more usefully, plugged into any chess GUI that supports the UCI protocol such as the free Arena or commercial programs such as Shredder and Fritz.

Latest Java development version (JavaRival-0094.jar)

From the command line

You can run the Java version from the command line or under a GUI such as by using

java -jar /path/to/JavaRival-0094.jar

If this fails with a memory error, it may be necessary to increase the heap size, e.g…

java -Xms256 -Xmx256 -jar /path/to/JavaRival-0094.jar

From Arena

Under the Engine Management dialog in Arena, you can enter /path/to/java.exe in the Command Line section and -jar “/path/to/JavaRival-0094.jar” in the Command Line Parameters section.

From Shredder (and others)

Some GUIs such as Shredder require a standalone executable. The file below is a Windows EXE wrapper which will seek out a JRE at runtime. The wrapper was created with the Launch4j application.

Windows EXE Wrapper

C++ versions for Windows and MS-DOS

Previous Rival versions for MS-DOS, Windows and standalone UCI along with C++ sources can be found at this link.