+ // Add a bonus if a slider is pinning an enemy piece
+ if ( (Piece == BISHOP || Piece == ROOK || Piece == QUEEN)
+ && (PseudoAttacks[Piece][pos.king_square(Them)] & s))
+ {
+ b = BetweenBB[s][pos.king_square(Them)] & pos.occupied_squares();
+
+ assert(b);
+
+ if (!(b & (b - 1)) && (b & pos.pieces(Them)))
+ score += ThreatBonus[Piece][type_of(pos.piece_on(first_1(b)))] / 2;
+ }
+