HIARCS

HIARCS is a proprietary UCI chess engine developed by Mark Uniacke. Its name is an acronym standing for higher intelligence auto-response chess system. Because Hiarcs is written portable in C, it is available on multiple platforms such as Pocket PC, Palm OS, PDAs, iOS, Microsoft Windows and Mac OS X.

HIARCS opening book authors over time were Eric Hallsworth, Sebastian Böhme and Harvey Williamson, who is also operating HIARCS regularly at various computer chess tournaments. HIARCS author Mark Uniacke said in a 2011 video interview that one of his current priorities in development is improving HIARCS to play in a more "human-like fashion" at different Elo strengths.

The first version of HIARCS was written in 1980 in PDP-11 Basic, when Mark Uniacke was only 15 years old. Subsequent versions were also written in interpreted Basic, which meant that the program was rather slow. To compensate for this, Mark developed some heuristics to guide the program's search and evaluation in a more 'targeted' way. This resulted in a program that relied on positional algorithms, rather than search depth.

At the end of the 80s, HIARCS was rewritten in C, and soon competed in computer chess tournaments. In 1991, Hiarcs went commercial and Hiarcs 1.0 was released for PCs and the MS-DOS operating system. Version 11, the first version to support multiprocessing, was released in December 2006. Since Version 12, it has been marketed as a Chessbase engine, and is sold alongside the Fritz GUI. HIARCS 12.1 and 13 are the engines in Pocket Fritz by Chessbase. Since Version 14, released in August 2012, HIARCS has been sold along with its own GUI (Chess Explorer) available on Mac OS X and Windows.