🔍 SEE pruning

src/Lynx/Configuration.cs

@@ -179,6 +179,15 @@ public sealed class EngineSettings
     [SPSA<int>(0, 6, 0.5)]
     public int SEE_BadCaptureReduction { get; set; } = 2;
 
+    [SPSA<int>(1, 10, 0.5)]
+    public int SEE_Pruning_MaxDepth { get; set; } = 5;
+
+    [SPSA<int>(-150, -50, 5)]
+    public int SEE_Pruning_Noisy_DepthScalingFactor { get; set; } = -99;
+
+    [SPSA<int>(-100, 0, 5)]
+    public int SEE_Pruning_Quiet_DepthScalingFactor { get; set; } = -50;
+
     [SPSA<int>(1, 10, 0.5)]
     public int FP_MaxDepth { get; set; } = 7;
 

src/Lynx/Search/NegaMax.cs

@@ -292,6 +292,24 @@ private int NegaMax(int depth, int ply, int alpha, int beta, bool parentWasNullM
 
                         break;
                     }
+
+                    // 🔍 SEE pruning
+                    if (depth <= Configuration.EngineSettings.SEE_Pruning_MaxDepth)
+                    {
+                        var threshold = isCapture
+                            ? Configuration.EngineSettings.SEE_Pruning_Noisy_DepthScalingFactor * depth
+                            : Configuration.EngineSettings.SEE_Pruning_Quiet_DepthScalingFactor * depth;
+
+                        if (!SEE.HasPositiveScore(position, move, threshold))
+                        {
+                            // After making a move
+                            Game.HalfMovesWithoutCaptureOrPawnMove = oldHalfMovesWithoutCaptureOrPawnMove;
+                            Game.RemoveFromPositionHashHistory();
+                            position.UnmakeMove(move, gameState);
+
+                            continue;
+                        }
+                    }
                 }
 
                 PrefetchTTEntry();