Sameshi is a highly compact chess engine designed to support a limited set of the game’s rules. Its core file, sameshi.h, measures an impressive 1.95 KB.
Core Features
The engine’s fundamental components include:
- A 120-cell mailbox board for game representation.
- A negamax search algorithm for move evaluation.
- Alpha-beta pruning to optimize the search process.
- An evaluation function based solely on material advantage.
- Move ordering that prioritizes captures.
- Comprehensive legal move validation, covering check, checkmate, and stalemate conditions.
It is important to note that certain chess rules are not implemented in Sameshi, including castling, en passant, pawn promotion, repetition draws, and the 50-move rule.
Engine Strength
Sameshi demonstrates a competitive strength, estimated at approximately 1170 Elo (with a 95% confidence interval of 1110-1225). This rating was determined through 240 games played against Stockfish at various levels (1320-1600). The testing was conducted with a fixed search depth of 5, adhering to Sameshi’s constrained rules, and limiting games to a maximum of 60 plies.
