Uploaded January 2023 | Updated September 2026, 2 weeks ago
In this journal entry I'll spend some time with Tim Hartnell's chess program (from his Giant Book of Computer Games) that I converted to the ZX81 as a kid. I recently updated it a bit, giving it a better playing board plus the ability to re-enter a move. I wanted to find out its relative ELO rating, a score used to identify a chess player's strength. I'll play it against a chess engine that can play at various lower ratings, starting at 400 and then going up (a score of 200 is considered just playing random legal moves with no other strategy).
Index:
0:05 Introduction
8:44 Tim Hartnell's chess vs modern engine
15:45 Explanation of final rating
16:39 Epilogue and ZX81 chess BASIC listing
In this journal entry I'll spend some time with Tim Hartnell's chess program (from his Giant Book of Computer Games) that I converted to the ZX81 as a kid. I recently updated it a bit, giving it a better playing board plus the ability to re-enter a move. I wanted to find out its relative ELO rating, a score used to identify a chess player's strength. I'll play it against a chess engine that can play at various lower ratings, starting at 400 and then going up (a score of 200 is considered just playing random legal moves with no other strategy).
Index:
0:05 Introduction
8:44 Tim Hartnell's chess vs modern engine
15:45 Explanation of final rating
16:39 Epilogue and ZX81 chess BASIC listing
