Release of engine version 0.91

README.md

@@ -3,26 +3,27 @@ K2, the chess engine
 
 Author: Sergey Meus, Russian Federation.
 
-Latest release version: 0.87 (October, 2016).
+Latest release version: 0.91 (July, 2018).
 
 Strength: about 2600 Elo.
 
-Link for download executable: https://yadi.sk/d/VRKs5oiWwuXAh
+Link for download executable: https://github.com/serg-meus/k2/releases/091
+http://sdchess.ru/russian_engines.htm
 
 Main features:
 - supports both UCI and XB protocol;
-- chess board represented as 120-element array (so-called 0x88 move generator);
+- 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, transposition table (TT);
-- quiescence search function with SEE cutoff and delta pruning, without TT;
+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 opponent pieces at distance less than 4 to king,
-penalty for wrong king placing and enemy rooks/queens on adjacent open files),
-paired bishops, bishop mobility, clamped rook penalty, rooks on open files,
+(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.