Rework check/pawn-push/recapture extension gating on real SEE (GetMoveSee, generalized from GetCheckSee), restrict LMR to leftover moves only, and tighten recapture's window back to 1x after measuring a 6.8x node blowup from sharing the wider window.

Head-to-head match at 1170 games confirms parity with the prior head (score=0.510, LLR still between bounds) -- landing as a neutral-or-better baseline rather than a regression.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/chess.h b/src/chess.h
index 4d7015e..16cdca9 100755
--- a/src/chess.h
+++ b/src/chess.h
@@ -1113,10 +1113,13 @@ typedef struct _COUNTERS
     struct
     {
         ULONG uPawnPush;
+        ULONG uPawnPushByQuarterPly[5]; // indexed by granted amount / QUARTER_PLY
         ULONG uCheck;
+        ULONG uCheckByQuarterPly[5];    // indexed by granted amount / QUARTER_PLY
         ULONG uMateThreat;
         ULONG uRecapture;
         ULONG uOneLegalMove;
+        ULONG uOneLegalMoveByQuarterPly[5]; // indexed by granted amount / QUARTER_PLY
         ULONG uNoLegalKingMoves;
         ULONG uMultiCheck;
         ULONG uSingularMove;
@@ -3247,7 +3250,7 @@ ComputeReactionToCheckExtension(IN OUT SEARCHER_THREAD_CONTEXT *ctx,
                                 IN OUT INT *piOrigExtend);
 
 SCORE
-GetCheckSee(IN SEARCHER_THREAD_CONTEXT *ctx,
+GetMoveSee(IN SEARCHER_THREAD_CONTEXT *ctx,
             IN MOVE mv,
             IN ULONG uMoveNum);
 
@@ -3258,7 +3261,8 @@ ComputeMoveExtension(IN OUT SEARCHER_THREAD_CONTEXT *ctx,
                      IN ULONG uMoveNum,
                      IN SCORE iRoughEval,
                      IN ULONG uDepth,
-                     IN SCORE iCheckSee,
+                     IN SCORE iMoveSee,
+                     IN FLAG fIsLeftoverMove,
                      IN OUT INT *piExtend);
 
 SCORE