Classic Chess
Full chess on the same board and with the same soldiers, so a chess player can start on familiar ground and drift into CHECKFIRE.
The rules #
Orthodox chess: no fire, straight-only pawns with the double step and en passant, castling on both wings, promotion, checkmate, stalemate, threefold repetition, the fifty-move rule and insufficient-material draws. The move generator is verified move-for-move against the standard perft reference positions.
Classic Chess is a ruleset on the match setup screen, next to Core Rules and Special Abilities, and the host can choose it for an online match too.
The engines #
The built-in engine is CHECKFIRE's own: alpha-beta with quiescence, a transposition table, iterative deepening and a tapered piece-square evaluation.
| Tier | Play |
|---|---|
| Recruit | Depth 2, deliberate blunders roughly one move in three |
| Soldier (default) | Depth 4, about 0.35 s per move |
| Veteran | Depth 6, about 0.9 s per move |
| Commander | Depth 9, about 1.8 s per move |
| Grand Marshal | Stockfish at full strength, run as a separate process |
Grand Marshal is optional. Enable Stockfish in Settings and accept its GPL v3 licence; the engine ships in its own folder and the tier is hidden on any platform that cannot launch a process. Stockfish is by the Stockfish developers and is not part of CHECKFIRE's own code; see credits.