}
// Step 9. Internal iterative deepening
- if ( depth >= IIDDepth[PvNode]
- && ttMove == MOVE_NONE
+ if ( depth >= IIDDepth[PvNode]
+ && (ttMove == MOVE_NONE || (PvNode && tte->depth() <= depth - 4 * OnePly))
&& (PvNode || (!isCheck && ss[ply].eval >= beta - IIDMargin)))
{
Depth d = (PvNode ? depth - 2 * OnePly : depth / 2);