diff --git a/src/Lynx/Model/Position.cs b/src/Lynx/Model/Position.cs
index d3c71f00d..e9262cc42 100644
--- a/src/Lynx/Model/Position.cs
+++ b/src/Lynx/Model/Position.cs
@@ -712,6 +712,11 @@ private int RookAdditionalEvaluation(int squareIndex, int pieceIndex, int pieceS
packedBonus += CheckBonus[(int)Piece.R] * checks;
+ if ((attacks & PieceBitBoards[pieceIndex]).CountBits() >= 2)
+ {
+ packedBonus += ConnectedRooksBonus;
+ }
+
return packedBonus;
}
diff --git a/src/Lynx/TunableEvalParameters.cs b/src/Lynx/TunableEvalParameters.cs
index d5785cd9f..d4d975155 100644
--- a/src/Lynx/TunableEvalParameters.cs
+++ b/src/Lynx/TunableEvalParameters.cs
@@ -6048,6 +6048,11 @@ public static class EvaluationParams
///
public const int BishopPairBonus = 4653086;
+ ///
+ ///
+ ///
+ public const int ConnectedRooksBonus = 4653086;
+
///
///
///