- // Secondly, add the squares which are attacked twice in that flank and
- // which are not defended by our pawns.
- b = (Us == WHITE ? b << 4 : b >> 4)
- | (b & attackedBy2[Them] & ~attackedBy[Us][PAWN]);
+ // Find the squares that opponent attacks in our king flank, and the squares
+ // which are attacked twice in that flank but not defended by our pawns.
+ b1 = attackedBy[Them][ALL_PIECES] & kf & Camp;
+ b2 = b1 & attackedBy2[Them] & ~attackedBy[Us][PAWN];