Vektor3 Chess for Mac

From Manfred Schubert:

Vektor3 is an award winning chess program for Mac OS X. It's features include a customizable chessboard with multiple piece sets, multiple documents, multithreading, support for variations, annotation editor with text styles, move annotations and diagrams, several playing levels, opening book, game analysis, position editor, PGN import and export, HTML publishing, speech, multiple undo and redo, and HTML help including rules of chess.