// Increase history value of the cut-off move
Value bonus = Value(int(depth) * int(depth));
Hist.update(pos.piece_moved(bestMove), to_sq(bestMove), bonus);
- Square prevSq = to_sq((ss-1)->currentMove);
- Refutation.update(pos.piece_on(prevSq), prevSq, bestMove);
+ if (is_ok((ss-1)->currentMove))
+ {
+ Square prevSq = to_sq((ss-1)->currentMove);
+ Refutation.update(pos.piece_on(prevSq), prevSq, bestMove);
+ }
// Decrease history of all the other played non-capture moves
for (int i = 0; i < playedMoveCount - 1; i++)