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Home * Engines * Dappet

the chess program by Dap Hartmann and Peter Kouwenhoven, competing all 18 consecutive Dutch Open Computer Chess Championships from 1981 until 1998. It further participated at the WMCCC 1988 in Almeria, the WCCC 1989 in Edmonton, the 3rd Computer Olympiad 1991, and various Aegon Tournaments. Dappet of the late 80s and 90s was written in Turbo Pascal and Assembler to run on an x86 based IBM PC or compatible. It used a 10x12 board [1]. It did not utilize the Butterfly Heuristic, proposed by Hartmann in conjunction with Butterfly Boards as a pure thought experiment [2].


from the WCCC 1989 booklet [3]:

Dappet uses the NegaScout algorithm enhanced with refutation tables, killer heuristic, history heuristic and transposition tables (700,000 entries) to search the game tree. The strategy used is basically brute force, with selective deepening of forced lines of play. The opening book consists of some 15,000 positions. 


At two occasions, the DOCCC 1986 and DOCCC 1994, to even the number of entries, a female version of Dappet was entered, Sylkar for Sylvia and Karin [4].

Selected Games

DOCCC 1997, round 5, Dappet - Zzzzzz

[Event "DOCCC 1997"]
[Site "Alphen a/d Rijn NED"]
[Date "1997.11.23"]
[Round "05"]
[White "Dappet"]
[Black "Zzzzzz 4.2"]
[Result "1-0"]

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.c3 Nf6 5.d4 exd4 6.cxd4 Bb4+ 7.Bd2 Bxd2+
8.Nbxd2 Nxe4 9.d5 Nxd2 10.Qxd2 Ne7 11.d6 cxd6 12.O-O-O Qc7 13.Qf4 O-O
14.Kb1 Ng6 15.Qe4 Ne5 16.Bd5 g6 17.Rhg1 a6 18.Rge1 Nc6 19.Ng5 Kg7 20.Qh4
h5 21.Nxf7 Rxf7 22.Bxf7 b6 23.Bd5 Bb7 24.Bxc6 1-0

External Links


  1. Dap Hartmann (2009). A Thesis is more than three unrelated Ideas. Review, ICGA Journal, Vol. 32, No. 2
  2. Dap Hartmann (1988). Butterfly Boards. ICCA Journal, Vol. 11, Nos. 2/3, pp. 64-71.
  3. Kings Move - Welcome to the 1989 AGT World Computer Chess Championship. Edmonton, Alberta, Canada, Courtesy of Peter Jennings, from The Computer History Museum
  4. Jaap van Oosterwijk Bruyn (1986). Nona retains her Title. ICCA Journal, Vol. 9, No. 3, pp. 160

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