PETCHESS 4000 from Philidor Software came out in 1981. The author is unknown, however a similar looking program called MICROCHESS 3 was released in 1984, therefore it is possible that the chess engine was written by Peter Jennings who wrote the original MICROCHESS in 1977 for the KIM-1. It is unclear whether the program was modified for the MICROCHESS 3 version. The chess board and screen have a different color in PETCHESS 4000.

To access the game options, you press: ] then followed by the letter. ie ] + L = Levels, ] + N = New Game. ] + H = Help (The Help screen will show you all the options and setup commands available in the game).

The game is enjoyable to play and has a fairly decent openings library.

You can see MICROCHESS 3 for the Commodore 64 here:

Estimated rating for PETCHESS 4000 is 1100 - 1200 ELO (1300 - 1400 USCF).

The Spacious-Mind Active game results (shown above) are from games played with a Commodore 64 or 128. Game Software was loaded from a PC into a Commodore 64/128 using C64TPC. C64TPC connects to the Commodore 64/128 via the Disk Drive Port and links to the PC with a Serial Cable. Playing PETCHESS 4000 with an Emulator should play exactly the same as using a Commodore 64 or 128.

The game example below originates from the C64 Open Championship and was played with a real Commodore 64 or 128 with software loaded using C64TPC.