a commercial chess program by Don Dailey and Larry Kaufman. The engine was written in 8086 assembly language, the graphical user interface written in Turbo Pascal  . RexChess was the commercial successor of Rex, running on IBM PC and compatibles under MS-DOS. RexChess played the Aegon 1991 with 3½ out of 6, losing from David Bronstein, winning versus Tim Krabbé and drawing from Jeroen Piket, Harvard Cup 1991, and Aegon 1992.
Rexchess 2.30 Dos Screen 
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.
- Rexchess by José Carlos, CCC, January 08, 2004
- RexChess 230 Rybka Danger? by Mark, Rybka Forum, October 31, 2007
- La Máquina Preservadora 4. Don Dailey & Larry Kaufman by Luis a, Meca Foro, October 18, 2013