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Fritz (early versions called Knightstalker in the USA),
a series of chess programs published by ChessBase, until Fritz 13 the engine developed by primary author Frans Morsch and Mathias Feist, Deep Fritz 14 released in November 2013 by Gyula Horváth [1], and Fritz 15 in November 2015 by Vasik Rajlich [2] [3]. Fritz 1-13 were based on Frans Morsch's program Quest, and was first marketed by ChessBase in 1991 as MS-DOS program with its own Graphical User Interface [4] . Since version 4, released in 1996, Fritz ran on Windows, and is until today one the world’s most popular and successful chess programs. At the WCCC 1995, Fritz became World Computer Chess Champion, winning a notable game versus Deep Blue prototype [5] and the playoff [6] against Star Socrates.
Unser Fritz 2/3, protego sundial and machine hall [7]


The given name Fritz originated as a German nickname for Friedrich, or Frederick (der "Alte Fritz" was a nickname for King Frederick II of Prussia, and of Frederick III, German Emperor [8]), as well as for similar names including Fridolin. Fritz was also a name given to German troops by the British and others in the first and second world wars, equivalent to Tommy, as the British troops were called by German and other troops [9] . Creative ChessBase partner Olaf Oldigs [10] had suggested the name Fritz for the chess program [11] .

Selected Games

WCCC 1995, round 5, Deep Blue Prototype - Fritz [12]
[Event "WCCC 1995"]
[Site "Chinese University HKG"]
[Date "1995.05.29"]
[Round "5"]
[White "Deep Blue Prototype"]
[Black "Fritz"]
[Result "0-1"]
1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e5 6.Ndb5 d6 7.Bg5 a6 8.Na3 b5
9.Bxf6 gxf6 10.Nd5 f5 11.Bd3 Be6 12.Qh5 f4 13.O-O Rg8 14.Kh1 Rg6 15.Qd1 Rc8
16.c4 Qh4 17.g3 Qh3 18.Qd2 f3 19.Rg1 Rh6 20.Qxh6 Qxh6 21.cxb5 Bxd5 22.exd5
Nb4 23.Bf5 Rc5 24.bxa6 Nxa6 25.Nc2 Qd2 26.Ne1 Rxd5 27.Nxf3 Qxf2 28.Be4 Ra5
29.Rg2 Qe3 30.Re1 Qh6 31.Bc6+ Kd8 32.a3 f5 33.Rc2 Rc5 34.Rxc5 Nxc5 35.Rf1
Be7 36.a4 f4 37.gxf4 Qxf4 38.Rg1 Nxa4 39.b4 Qxb4 0-1

Null Move

Frans Morsch, as well as other Dutch computer chess programmers like Bart Weststrate and Dap Hartmann [13] , did early experiments with recursive null move pruning in the late 80s, likely after it was discussed at the panel workshop during the WCCC 1986 after Don Beal's talk covering null move [14] [15] . Frans Morsch told Chrilly Donninger about recursive null move, who popularized it by his Null Move and Deep Search paper in the ICCA Journal 1993 [16] .


from the ICGA tournament page [17] :


Fritz is built around a selective search technique known as null-move search. As part of its search, Fritz allows one side to move twice (the other side does a null-move). If the position after the null-move does not return a high value in the evaluation function, then clearly the first of the two moves did not contain a threat. This applies to 95% of the moves in a search. Detecting such moves before they are searched to the full depth is an excellent method to speed-up the search. In its latest version, Fritz manages a 10-times speed-up over a version without the null-move search. Selective search unavoidably introduces oversights, but these are few. In tournaments against humans and other programs, Fritz has proven to be a tough opponent when defending difficult positions.


Fritz won the ICCA chess computer world championship in Hong Kong 1995 beating a prototype of the Deep Blue chess computer. It obtained the best computer result in the 1996 man-computer Aegon tournament. Fritz is build around a selective search technique known as the null-move search. Move generators, evaluation functions and data structures have been designed specially to maximise the effectiveness of the null-move search. If anything, Fritz is fast. The search engine is written in highly optimised assembly language. The present version searches at a rate of one thousand processor cycles per position. The openings book was constructed from grandmaster games. Fritz learns from his games and adjusts the probability weights in the openings book automatically.


Fritz is build around a selective search technique known as the null-move search. As part of its search, Fritz allows one side to move twice (the other side does a null-move). This allows the program to detect weak moves before they are searched to their full depth. Move generators, evaluation functions and data structures have been designed to maximize the effectiveness of the null-move search. Fritz is the winner of the previous computerchess world championship in Hong Kong 1995. 1993 Fritz tied for 1st place in a Blitz tournament in Munich with the complete world elite. It scored the best computer result in the 1996 man-computer Aegon tournament. In 1998 Fritz was leading the prestigious Swedish rating list. It won an active chess tournament Frankfurt 1998 with a full point ahead of 36 grandmasters.

Deep Fritz

Deep Fritz is the engine designed for multiprocessing and parallel search, it first appeared as Deep Fritz 6 in 2000. Since version 14 by Gyula Horváth, Deep is obligatory.

Fritz SSS

A Fritz version called SSS [18] or even SSS* [19] that played the Dutch Chess Championship 2000 in Rotterdam, becoming third with 7/11 behind Loek van Wely, and Jeroen Piket, shared with Sergei Tiviakov and Paul van der Sterren [20], was not related to the SSS* search algorithm, but to the three primary sponsors of the event [21] [22].

Pocket Fritz

Pocket Fritz is a chess program for PocketPC Personal digital assistants (PDAs). Pocket Fritz 4 is based on Hiarcs by Mark Uniacke, Pocket Fritz 2 used a port of Shredder by Stefan Meyer-Kahlen [23] .

Fritz User Interface

Fritz 1

The original Fritz MS-DOS Graphical User Interface from 1991 [24]

Fritz 5

Fritz 5 Windows Graphical User Interface [25]

Deep Fritz 14

Recent Deep Fritz GUI is suited to run other ChessBase or UCI engines with either using its own proprietary protocol, as well as the UCI protocol.

Deep Fritz 14 GUI [26]


Book Authors

See also

Release Dates

Frans Morsch

  • Fritz 1.0 : 1991
  • Fritz Deluxe : 1992
  • Fritz 2.0 : 1992 or 1993
  • Fritz 2.51 : 1994
  • Fritz 3.0 : 1994 or 1995
  • Fritz 4.0 : 1995 or 1996
  • Fritz 5.0 : 1997 or 1998
  • Fritz 5.32 : 1998 or 1999
  • Fritz 6 : 2000
  • Deep Fritz : 2000
  • Fritz 7 : July 2001
  • Fritz Bahrain : November 2002
  • Deep Fritz 7.0 : 2003
  • Fritz 8 : September 2003
  • X3D Fritz : November 2003
  • Fritz 8 Bilbao : December 2004
  • Deep Fritz 8.0 : 2005
  • Fritz 9 : December 2005
  • Fritz 10 : October 2006
  • Deep Fritz 10 : December 2006
  • Fritz 11 : November 2007
  • Deep Fritz 11 : November 2008
  • Fritz 12 : October 2009
  • Deep Fritz 12 : July 2010
  • Fritz 13 : October 2011
  • Deep Fritz 13 : June 2012

Gyula Horváth

  • Deep Fritz 14 : November 2013

Vasik Rajlich

  • Fritz 15 : November 2015
  • Fritz 16 : November 2017



Forum Posts

1991 ...

1995 ...

2000 ...

2010 ...

2015 ...

External Links

Chess Engine


ChessBase News

Rating Lists



  1. ^ New Fritz author? by John Hartmann, CCC, November 19, 2013
  2. ^ Fritz 15 - English Version, ChessBase Shop
  3. ^ Fritz 15 engine - questions and answers by Albert Silver, ChessBase News, January 04, 2016
  4. ^ Christmas dinner on a train – meet the ChessBase team from ChessBase News, December 23, 2003
  5. ^ Fabian Mäser (1995). Fritz vs. Deep Blue: Opening Book vs, Opening Book. Computer Chess Reports Vol. 5 No. 2 pp. 22, WCCC 1995
  6. ^ Shatin 1995, Chess, Round 6, Game 1
  7. ^ Former coal mine Unser Fritz 2/3 in Herne, North Rhine-Westphalia, Germany, now artist-studio, exhibition and event space, and part of The Industrial Heritage Trail of the Ruhr area - Image of protegohaube (flame arrester) as gnomon of a sundial and machine halls behind by Gerd Isenberg, bike tour, September 16, 2016. Unser Fritz/Crange is further district of Herne (Wanne), famous for its funfair Cranger Kirmes, and SV Unser Fritz the local chess club - eponym of the coal mine was Frederick III, German Emperor, see also Künstlerzeche Unser Fritz 2/3 - Chronik (German) and 2011 Image by Frank Vincentz
  8. ^ Der alte Fritz (1928) Wikipedia.de (German)
  9. ^ Fritz from Wikipedia
  10. ^ Olaf Oldigs - Google+
  11. ^ The ChessBase Christmas Party – part 1, ChessBase News, December 28, 2010
  12. ^ Shatin 1995, Chess, Round 5, Game 4
  13. ^ Chrilly Donninger (1994). Die Kunst des Nichtstuns. CSS 2/94, pdf (German)
  14. ^ Re: SOMA by Ed Schroder, CCC, August 26, 2009
  15. ^ Re: Search or Evaluation? by Mark Uniacke, Hiarcs Forum, October 14, 2007
  16. ^ Chrilly Donninger. (1993). Null Move and Deep Search: Selective-Search Heuristics for Obtuse Chess Programs. ICCA Journal, Vol. 16, No. 3, pp. 137-143
  17. ^ Fritz' ICGA Tournaments
  18. ^ Comp Fritz SSS chess games - 365Chess.com
  19. ^ Jaap van den Herik (2000). De toekomst van het schaaken. Schaakmagazine, 5/2000, pdf hosted by Hein Veldhuis
  20. ^ NED-ch 2000 - 365Chess.com Tournaments
  21. ^ Fritz SSS uses *SSS? by Bas Hamstra, CCC, May 15, 2000
  22. ^ Re: Fritz SSS uses *SSS? by Robert Hyatt, CCC, May 15, 2000
  23. ^ Chess Programs for Pocket PC and Palm devices by Dr. Axel Schumacher
  24. ^ Septober - Computerschach by Herbert Marquardt
  25. ^ Septober - Computerschach by Herbert Marquardt
  26. ^ Deep Fritz 14 from ChessBase
  27. ^ Rodrigo Vásquez Schroder - Wikipedia
  28. ^ Measuring similarity native ChessBase engines by Ed Schröder

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