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Sigma GameWare
Ole K. Christensen
ole@sigmachess.com

Sigma Chess is a freeware, master strength Macintosh chess program for Mac OS X. The feature set includes: Optional HIARCS engine, UCI Engine support, Databases, PGN/EPD, basic desktop publishing, endgame databases, novice levels, a true perspective 3D board, ExaChess compatibility and much more. Sigma also runs on Classic Mac OS, but this is no longer officially supported.

About Sigma Chess

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Welcome to the Sigma Chess home page! If you own a Macintosh and you like chess, you should download Sigma Chess. You can:

Play chess against the strong built-in engine: Adjust the playing strength to your own level simply by setting the ELO rating for Sigma Chess, and choose among the many playing modes, levels and styles.

Play chess against the World Chess Championship strength HIARCS 13 and Deep Junior 12 engines bundled with Sigma Chess: Sigma Chess supports the UCI (Universal Chess Interface) protocol, so you can use other UCI chess engines for Mac OS X. Click here for a list.

Analyze and annotate games: Instruct Sigma Chess to annotate games with its analysis, or add your own free text annotations including diagrams and move suffixes. You can even write and print your own chess literature.

Maintain & access game collections/databases: The built-in database manager lets you filter and sort large game collections. Additionally you can import PGN game files that you have e.g. downloaded from the internet (see the Selected Chess Links). Sigma Chess can also be used as an engine from within ExaChess.

Customize the appearance & behavior of Sigma Chess: You can choose among the various piece sets, board types, types of move notation, colour schemes, the true perspective 3D board etc.

Sigma Chess Lite & Pro

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As of version 6.2, Sigma Chess is only released as FREEWARE including the full feature set of the previous Pro version.

Sigma Chess & Mac OS X 10.7

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Sigma Chess does unfortunately not run on the new Mac OS X 10.7 (Lion).

As of Mac OS X 10.7 (Lion), support for legacy PowerPC applications such as Sigma Chess has been discontinued.

Sigma Chess is such a legacy PowerPC application using the Carbon APIs, and the built-in engine is written mainly in PowerPC assembler. Therefore producing an Intel version (and switching to the Cocoa APIs) will more or less require a complete rewrite. Chess programming is just a hobby, and my spare time is limited, so I alas won't have time to move away from the legacy PowerPC/Carbon platform.

Mark Uniacke, author of Hiarcs, is currently working on bringing a native Chess GUI to Mac OS X. This should be ready before the end of 2011. Mark has made a page on his website here, where you can check the progress of this new GUI.

I am also considering releasing Sigma to the open source community at some point.

I apologize for the inconvience this is causing, but it's time for me (and Mac OS X) to move on. I would like to thank all of you for your feedback and support over the past 10 years.

/Ole

The Author

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Sigma Chess 6.2 is developed by Ole K. Christensen. If you have any questions or comments please check out the FAQ or send me an e-mail.