Cute Chess is a system to run chess engine-engine games and
tournaments. It works with any chess engines that implement the chess
engine communication protocol (CECP, also known as "xboard") or the
universal chess interface (UCI). It includes a QT-based graphical user
interface and a command line version, cutechess-cli, which is a very
low overhead program suitable in headless environments. Cute Chess also
supports chess variants (like Chess960), Polyglot  opening books, PGN
collections as opening books, and white's time control can be
different from black's.

Two example engines that can be used are gnuchess (included in
base Slackware) that uses the xboard protocol, and stockfish (in SBo)
that uses the UCI protocol. Many more chess engines are available, see
e.g. the list at https://www.chessprogramming.org/Engines
