Free and basic chess app for Mac OS X, with nice graphics and a built-in FEN viewer.

UCI Engine version of pChess for OS X. With version 1.9, you get both the stand-alone OS X application, and the UCI Engine (compatible with Sigma Chess and Stockfish).

pChess is a basic chess programme for Macintosh OS X, with nice graphics and a built-in FEN Viewer. Uses a classic Shannon type MiniMax search with Quiescence extensions and Alpha-Beta pruning. It supports Fischer games, copy/paste of FEN positions, and SAN Notation.

Cool Audio and Visual Brain features let you listen and see as it evaluates moves. Load and Save games, with unlimited Undo/Redo. The opening book includes over 10,000 moves from the ECO (Encyclopedia of Chess Openings). Runs at about 1500 ELO. Comes complete with FutureBasic 5 source code.