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a chess engine developed by Perola Valfridsson since 1998, which appeared in July 2002 as a surprisingly strong newcomer playing on ICC and FICS [1], supporting both, the Chess Engine Communication Protocol and UCI.

With portability and performance in mind, Ruffian is written in C, and a hybrid between bitboard and 8x8 board. It performs a PVS with null-move- and other forward pruning techniques as well as a few own algorithms and tricks [2]. One of the major evaluation terms is mobility based on pre-calculated tables considering various patterns [3] [4].
Ruffian, 1975 [5]


ICT 2004 winners: Chrilly Donninger, Erdogan Günes (Hydra 2nd), Stefan Meyer-Kahlen (Shredder 1st),
Johan Havegheer (Ruffian 3rd), Vincent Diepeveen (Diep 3rd) [6]


Ruffian was shared winner of the CCT5 and lonesome winner of the DOCCC 2003 supported by book author Đorđe Vidanović, operated by Johan Havegheer, Frank Quisinsky and Leo Dijksman [7] [8], winner of the (unofficial) Swedish Championship in 2003 [9], and further played a strong CCT6 and ICT 2004.

Free Ruffian

The free Windows versions 1.0.0 and 1.0.1 from September 2002 are still available for download [10].

Commercial Ruffian

In 2003, Ruffian 2 went commercial, first bundled with Chess Assistant by Convekta, where Victor Zakharov mentions Dann Corbit was a big help [11], and further with the otherwise free Arena GUI, CD production by Frank Quisinsky and distribution by Schachversand Niggemann [12], and soon as bundle with ChessPartner by Lokasoft [13]. Ruffian is base of the chess AI in Kasparov Chessmate [14] [15], with Perola Valfridsson credited as author by MobyGames [16]. The initial hype about Ruffian's commercialization was apparently detrimental to its authors motivation to continue the development [17]. In conjunction with the upcoming strong free engines catching up, this was slowly but surely the fall of the commercial endeavor [18].

See also

Forum Posts




2005 ...

2015 ...

External Links

Chess Engine



  1. ^ What is Ruffian? by Bas Hamstra, CCC, July 24, 2002
  2. ^ Ruffian, the replacement to ABBA, Interview with Perola Valfridsson, October, 2002, by Frank Quisinsky et al., hosted by Ed Schröder and playwitharena
  3. ^ Ruffian 2.0: 3 Euro - Schachversand Niggemann
  4. ^ Ruffian's Secret? by Steve Maughan, CCC, November 23, 2003
  5. ^ Ruffian, Filly Triple Crown winner, Image courtesy of John Bellucci, from On the 30th Anniversary of Ruffian’s Last Race by Lyn Lifshin
  6. ^ Photos from the old CSVN site
  7. ^ Participants 23rd Open Dutch Computer-Chess Championship 18, 19, 25, 26 Oct. 2003; Leiden, Netherlands old CSVN site
  8. ^ Dutch Open Leiden final ranking - Ruffian Champion by Theo van der Storm, CCC, October 26, 2003
  9. ^ iSMDS-03 (unofficial) Swedish Championship 2003 by Albert Bertilsson
  10. ^ ruffian chess engine | Downloads
  11. ^ ChessAssistance.com A talk with Victor Zakharov, head of Convekta development, part b by Robert Pawlak, February 14, 2003
  12. ^ Arena 1.0 / Ruffian 2.0 ... information! by Frank Quisinsky, CCC, November 21, 2003
  13. ^ Good news for Ruffian Lovers from outside europe by Johan Havegheer, CCC, February 21, 2004
  14. ^ Kasparov Chessmate review by Alastair Scott, CCC, July 12, 2003
  15. ^ Kasparov Chessmate from Wikipedia
  16. ^ Perola Valfridsson from MobyGames
  17. ^ Re: CSVN Leiden (Ruffian and Sjeng missing) by Johan Havegheer, CCC, June 01, 2005
  18. ^ Ruffian 2.0: 3 Euro - Schachversand Niggemann

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