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Home * Engines * Rex

T-Rex skull [1]

a chess program written in 1985 by Don Dailey in Pascal, supported by chess advisor Sam Sloan, in 1987 superseded by Larry Kaufman [2] . In 1986, Don took the first big step by deciding to rewrite the program in assembly language, which roughly tripled the speed. Also, he created a special rule based language for chess masters (i.e. Larry Kaufman) to use to "teach" Rex how to evaluate a position.

Rex played the 17th ACM Tournament 1986 in Dallas, the 5th and 6th World Computer Chess Championships in Cologne 1986 and Edmonton 1989, and was forerunner of the commercial program RexChess.

Images & Games

Awit - Rex


WCCC 1986, round 4, Kaare Danielsen, Tony Marsland, Don Dailey, ..., Sam Sloan, Awit - Rex [3] [4]

[Event "WCCC 1986"]
[Site "Cologne, Germany"]
[Date "1986.06.14"]
[Round "4"]
[White "Awit"]
[Black "Rex"]
[Result "1-0"]

1.b3 e5 2.Bb2 Nc6 3.e3 d5 4.Bb5 Qg5 5.Nf3 Qxg2 6.Rg1 Qh3 7.Bxe5 Bg4 8.Rg3
Bxf3 9.Qxf3 Qh6 10.Qxd5 Ne7 11.Bxc6+ bxc6 12.Qf3 Nd5 13.Qg4 Qxh2 14.Bxg7 Bxg7
15.Qxg7 Ke7 16.Qe5+ Kd7 17.Na3 Ne7 18.Qd4+ Ke6 19.Qe4+ Kd7 20.Rg7 Qh5 21.Nc4
Ke8 22.Ne5 f5 23.Qg2 Qh6 24.Nxc6 Nxc6 25.Rxc7 Kf8 26.Rxc6 Qg7 27.Rf6+ Qxf6
28.Qxa8+ Kf7 29.Qxa7+ Kf8 30.d4 Ke8 31.Ke2 Kf8 32.c4 h6 33.a4 Rg8 34.a5 Rg7
35.Qc5+ Re7 36.a6 f4 37.a7 f3+ 38.Kf1 Kg8 39.a8=Q+ Kh7 40.Qh5 Rf7 41.Ra6 Kg7
42.Rxf6 Rxf6 43.Qe5 h5 44.Qxf3 1-0

Shess - Rex


WCCC 1986, round 5, Ard van Bergen, Sam Sloan, Ossi Weiner, Don Dailey [8] , Rex - Shess [9]

[Event "WCCC 1986"]
[Site "Cologne, Germany"]
[Date "1986.06.15"]
[Round "5"]
[White "Shess"]
[Black "Rex"]
[Result "0-1"]

1.e4 e5 2.Nf3 f5 3.Nxe5 Qf6 4.Nc4 fxe4 5.Nc3 Qf7 6.Nxe4 d5 7.Ne5 Qf5
8.Bb5+ c6 9.Be2 Qxe4 10.Nf3 Bf5 11.c3 Qc2 12.Qxc2 Bxc2 13.O-O Bd6 14.d4
Nf6 15.Be3 O-O 16.Rae1 Nbd7 17.Kh1 b5 18.b3 Rfe8 19.c4 bxc4 20.bxc4 dxc4
21.Bxc4+ Kh8 22.Ng5 Bg6 23.f4 Nd5 24.Bxd5 cxd5 25.f5 Bb4 26.fxg6 Bxe1
27.Nf7+ Kg8 28.gxh7+ Kxh7 29.Rxe1 Kg8 30.Ng5 Rac8 31.Kg1 Rc2 32.a3 Rc3
33.Kf2 Rxa3 34.h4 Nf6 35.Kf3 Rb3 36.g3 Nh5 37.Nh3 Nxg3 38.Nf4 Nf5 39.Nxd5
Rd3 40.h5 Nxd4+ 41.Kf4 Ne6+ 42.Kg4 Rxd5 43.Bxa7 Ra8 44.Rxe6 Rxa7 45.Re8+
Kh7 46.Re4 Raa5 47.Kf3 Rxh5 48.Ke3 Ra3+ 49.Kf4 Rh4+ 50.Ke5 Ra5+ 51.Kd4
Ra4+ 52.Kd5 Rhxe4 53.Kc5 Ra5+ 54.Kd6 Rd4+ 55.Ke6 Kg8 56.Ke7 Re5# 0-1



by Larry Kaufman from the USOCCC 1987 report [10] :

As for Rex IV, by Don Dailey and myself, we were quite pleased to tie with Fidelity Chessmaster for top PC, although they won in tiebreak points. Had repetition detection been added before the first round instead of after we would gave picked up half a point then. Rex is unique in that it allows a chess master with minimal programming expertise (i.e. myself) to input chess knowledge directly into the program without bothering the programmer. Whether it will become commercial is not yet clear. 

From Rex to Rexchess

by Larry Kaufman from The Rexchess Story [11] :

The next step forward came when Novag's Dave Kittinger, Don and I jointly worked out how to do an effective selective search program. Dave put these ideas into the Super Expert B and Super Forte B, while Don and I put them into Rex. So we decided to enter the 1989 World Computer Championship in Edmonton, although the program was very incomplete and not fully debugged. We scored 2 out of 5, around the middle of the PC programs, although our 20 MHz 368 was one of the slower machines present. Soon thereafter, Don quit his job to devote 2 months full-time to completing Rex and adding features necessary for a commercial program. 

See also

External Links

Chess Program



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