+ // Calculate new depth for this move
+ newDepth = depth - 1;
+
+ // Step 13. Pruning at shallow depth (~200 Elo)
+ if ( !rootNode
+ && pos.non_pawn_material(us)
+ && bestValue > VALUE_TB_LOSS_IN_MAX_PLY)
+ {
+ // Skip quiet moves if movecount exceeds our FutilityMoveCount threshold
+ moveCountPruning = moveCount >= futility_move_count(improving, depth);
+
+ if ( !captureOrPromotion
+ && !givesCheck)
+ {
+ // Reduced depth of the next LMR search
+ int lmrDepth = std::max(newDepth - reduction(improving, depth, moveCount), 0);
+
+ // Countermoves based pruning (~20 Elo)
+ if ( lmrDepth < 4 + ((ss-1)->statScore > 0 || (ss-1)->moveCount == 1)
+ && (*contHist[0])[movedPiece][to_sq(move)] < CounterMovePruneThreshold
+ && (*contHist[1])[movedPiece][to_sq(move)] < CounterMovePruneThreshold)
+ continue;