OliThink(5) is a free and open source chess engine.
One of the main aims was to create a strong engine with minimalistic and clear code. OliThink has no chess knowledge except mobility. The size of the source code has never exceeded 50kByte. Everything in the code is unique, there is no copy of other engines.
In order to play chess a chess GUI like xboard, cutechess, arena etc. is necessary. OliThink understands CECP (xboard).
In this repository there is a history of sources and executables for Linux, MacOSX and Windows. OliThink has been translated into a Jave engine, which is updated regularly.