// to search the moves. Because the depth is <= 0 here, only captures,
// queen promotions and checks (only if depth == 0) will be generated.
bool pvNode = (beta - alpha != 1);
// to search the moves. Because the depth is <= 0 here, only captures,
// queen promotions and checks (only if depth == 0) will be generated.
bool pvNode = (beta - alpha != 1);