K2, the chess engine
Author: Sergey Meus, Russian Federation.
Latest release version: 0.91 (July, 2018).
Strength: about 2600 Elo.
- supports both UCI and XB protocol;
- chess board represented as two 8x8 arrays for pieces and attack tables;
- alpha-beta search function with such improvements as: principal variation search, null move pruning, late move reduction and pruning, static exchange evaluation (SEE), futility pruning, killer moves heuristic, history heuristic, check extension, recapture extension, one reply extension, transposition table (TT);
- quiescence search function with SEE cutoff and delta pruning, with TT support;
- evaluation function with separate middle- and endgame terms such as material, piece-square tables, some pawn terms (passers, connected passers, unstoppable, double, isolated, passer closed to king, gaps in pawn structure), king safety (pawn shelter, penalty for squares attacked by enemy pieces near the king, paired bishops, piece mobility, rooks on open files, rooks on 7th and 8th rank, some endgame cases such as KPk, KN(B)k, KN(B)kp, KN(B)N(B)k, KN(B)Pk, pawn absence for both sides, opposite-colored bishops.
K2 is a hobby project, the aim is to have some fun with experiments on chess algorithms.