- return piece_count(WHITE, BISHOP) == 1
- && piece_count(BLACK, BISHOP) == 1
- && !same_color_squares(piece_list(WHITE, BISHOP, 0), piece_list(BLACK, BISHOP, 0));
+ return piece_count(WHITE, BISHOP) == 1 && piece_count(BLACK, BISHOP) == 1
+ && opposite_color_squares(piece_list(WHITE, BISHOP, 0), piece_list(BLACK, BISHOP, 0));