Virtua Chess (1995)
VirtuaChess is the commercial version of the Ecume and Cumulus 2 chess programs (which finished second in the blitz tournament in Munich and which tied 2nd/3rd in the 7th World Championships in Madrid). It runs on a PC with MSDOS and can use all of the available memory for its hash tables. It has a splendid graphical interface written by the French firm Titus. Most of the chess engine is written in 32 bit assembler, and the program includes dynamic evaluation of king safety and pawn structure. It is based on PVS and uses null-move pruning. The program has perfect knowledge of KPK endgames. The evaluation function attempts to build plans whenever it recognizes important features in a position. VirtuaChess runs at 20,000 nodes per second on a Pentium 90.