Sigma Chess

Play classic chess against the computer with a colourful board, move record and a library of historical games.

Ole Kjær Christensen and Kaare Danielsen, 1998

Sigma Chess gameplay

Play the original Sigma Chess 4.0 Lite freeware distribution. Drag a white piece to a legal square; the computer responds as black. The board starts at five minutes per player. Analyze → Stop interrupts a search and plays the best move found. Use File → New Game when it is your turn to start again.

Bounded native verification covers e2–e4, d2–d4, and the computer replies e7–e6, d7–d5 with the move record updated. Optimized browser verification also passes both player moves and computer replies. The public v0.91.0 player also passes both moves and computer replies from the exact hosted archive; public evidence. Complete matches, sustained search, other modes, saving and audio remain unverified. The original Lite edition retains its feature limits, including unsavable libraries and limited transposition tables.

This original main game is 68K only. The included PPC endgame generators are auxiliary tools and are not counted as a second game or a PPC game port. The complete original archive retains all 164 files and distribution notices.

License

Licensing information recorded for this game archive. These terms are separate from the Systemless runtime and website licenses.

Game archive

License: Original Sigma Chess 4.0 Lite freeware distribution notice
Rights holder: Ole Kjær Christensen and Kaare Danielsen
Redistribution: Recorded as permitted

Permission

The original Read me! dated April 29, 1998 expressly permits free distribution of Lite 4.0 in its original form and requests that all sample games, collections, libraries and endgames be retained. The main executable also states that Lite is freely distributable and may not be modified. The complete original package is preserved.

Notes

Intact 164-file distribution including main game, online manual, sample games, collections, opening library and original 68K/PPC endgame generators. No registration key or bypass. Main game has zero-byte data fork, nine CODE resources and no cfrg/PPC slice. PPC generators are auxiliary applications, not a PPC game port.

Sources

Screenshots, plugins and other files may have different terms. See their individual catalogue records in the repository source.