+ // Decrease reduction if opponent's move count is high (~1 Elo)
+ if ((ss-1)->moveCount > 7)
+ r--;
+
+ // Increase reduction for cut nodes (~3 Elo)
+ if (cutNode)
+ r += 2;
+
+ // Increase reduction if ttMove is a capture (~3 Elo)
+ if (ttCapture)
+ r++;
+
+ // Decrease reduction for PvNodes based on depth (~2 Elo)
+ if (PvNode)
+ r -= 1 + 12 / (3 + depth);
+
+ // Decrease reduction if ttMove has been singularly extended (~1 Elo)
+ if (singularQuietLMR)
+ r--;
+
+ // Increase reduction if next ply has a lot of fail high (~5 Elo)
+ if ((ss+1)->cutoffCnt > 3)
+ r++;
+
+ // Decrease reduction if move is a killer and we have a good history (~1 Elo)
+ if (move == ss->killers[0]
+ && (*contHist[0])[movedPiece][to_sq(move)] >= 3722)
+ r--;
+
+ ss->statScore = 2 * thisThread->mainHistory[us][from_to(move)]
+ + (*contHist[0])[movedPiece][to_sq(move)]
+ + (*contHist[1])[movedPiece][to_sq(move)]
+ + (*contHist[3])[movedPiece][to_sq(move)]
+ - 4082;
+
+ // Decrease/increase reduction for moves with a good/bad history (~25 Elo)
+ r -= ss->statScore / (11079 + 4626 * (depth > 6 && depth < 19));
+
+ // Step 17. Late moves reduction / extension (LMR, ~117 Elo)