Chess 9 has many new features:
- Most messages are now displayed as standard dialog boxes instead of in the in-game announcement
- Replay system that allows you to step through each move of a match
- Change difficulty (or enable a human opponent) on the fly, without having to start a new game
- More freedom for the name, size, and format of custom piece icons
- File and folder selection now uses standard dialog boxes instead of requiring you to type the file path into an entry field
- Menu bar instead of a mass of buttons
- Option to resize the board to better fit your monitor
- Option to choose the color of light and dark squares
- Extensive command line options
Unfortunately, Chess 9 is not compatible with save files from previous versions of Chess. The old version lists the location of each piece, while Chess 9 save files contain a series of moves.