First try, increase reduction for shuffling moves

src/search.cpp

@@ -568,7 +568,7 @@ namespace {
     Move ttMove, move, excludedMove, bestMove;
     Depth extension, newDepth;
     Value bestValue, value, ttValue, eval, maxValue, pureStaticEval;
-    bool ttHit, ttPv, inCheck, givesCheck, improving;
+    bool ttHit, ttPv, inCheck, givesCheck, improving, shuffling;
     bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture;
     Piece movedPiece;
     int moveCount, captureCount, quietCount;
@@ -1014,6 +1014,8 @@ namespace {
       // Update the current move (this must be done after singular extension search)
       ss->currentMove = move;
       ss->continuationHistory = &thisThread->continuationHistory[movedPiece][to_sq(move)];
+
+	  shuffling = pos.rule50_count() > 16;
 
       // Step 15. Make the move
       pos.do_move(move, st, givesCheck);
@@ -1029,6 +1031,9 @@ namespace {
           // Decrease reduction if position is or has been on the PV
           if (ttPv)
               r -= ONE_PLY;
+
+		  if (shuffling && pos.rule50_count() > 1)
+			  r += ONE_PLY;
 
           // Decrease reduction if opponent's move count is high (~10 Elo)
           if ((ss-1)->moveCount > 15)