DoubleCheck is a free UCI chess engine. It is not a complete chess program, but requires some UCI
compatible GUI in order to be used comfortably. Read the documentation for your GUI of choice for
information about how to use DoubleCheck with your GUI.
This version of DoubleCheck supports only 64 bit, and is single threaded (the search algorithm is
not parrallelised to take advantage of several cores).
DoubleCheck 1.0 engine and sources: