a free chess engine with Chess Engine Communication Protocol aka WinBoard support, developed by Maciej Pestka since 2002. Matacz became Champion of Poland in 2004 (uniform category), in 2006 (uniform category) and won the award of the best polish chess engine in 2007 and 2008 , and further played the CCT5 and CCT7.
- Matacz 1.02 : draw detection bug ? by Arnaud Lohéac, Winboard Forum, December 24, 2005
- Re: from WIN32 to Win64 compile with visual c++ 2005 express by Maciej Pestka, Winboard Forum, September 07, 2006
- Matacz1.3HT7 exit from Winboard by Pablo, Winboard Forum, July 04, 2007
- No more home page for Matacz? by Tony Mokonen, CCC, April 13, 2008