a commercial chess program by Wolfgang Delmare, developed in the late 80s and early 90s, and written in C. It was a 16-bit 8086 and later 32-bit x86 program running on PCs under MS-DOS with a pleasant GUI. Check Check was the first commercial chess program using own three and four men Endgame Tablebases , spending the "huge" amount of 16MB hard disk space.
Check Check Screen 
Check Check played the WMCCC 1990 in Lyon, and the first three International Paderborn Computer Chess Championships, IPCCC 1991, IPCCC 1992, and IPCCC 1993, as well the Aegon 1992, Aegon 1993, Aegon 1994 and Aegon 1995 Man-Machine Tournaments.
[Event "WMCCC 1990"] [Site "Lyon, France"] [Date "1990.01.01"] [Round "7"] [White "Check Check"] [Black "Nightmare (D)"] [Result "1-0"] 1.e4 e5 2.Bc4 Nf6 3.d4 exd4 4.Nf3 Nxe4 5.Qxd4 Nf6 6.Bg5 Be7 7.Nc3 c6 8.O-O-O d5 9.Rhe1 O-O 10.Bd3 b5 11.Kb1 Be6 12.Qh4 h6 13.Bxf6 Bxf6 14.Qb4 a5 15.Qc5 a4 16.Nd4 Bxd4 17.Qxd4 Qe7 18.f4 g6 19.f5 gxf5 20.Bxf5 Re8 21.g3 b4 22.Qg4+ Kh8 23.Qd4+ Kg8 24.Qg4+ Kf8 25.Bxe6 h5 26.Qf5 bxc3 27.Bxd5 Qd7 28.Qxh5 Kg7 29.Qg5+ Kf8 30.Bxf7 Kxf7 31.Rf1+ 1-0
- Check Check's ICGA Tournaments
- Check Check Grundpaket 3,5" from Schachversand Niggemann (German)
- KI – Machinelearning – Delmare.de