Gnuchess is a public domain chess program from unix.

There are several makefiles here adapted for different machines and
compilers.  I got it to compile under the Zortech C compiler.  I needed
to make a number of changes to the source code of gnuchess.c so I copied
it to a file named zgnuchss.c.  I could have just done this in gnuchess.c
since all of the changes are #ifdefed, but it looked more confusing.

gnuchess.exe is an executable that needs ANSI.SYS to be loaded.

It is possible to build gnuchesr.exe which uses simple ASCII text,
or gnucheso.exe which is similar to gnuchess.exe.