From bb4eb04a50244442f2925f6dad3b1b2fb1f82236 Mon Sep 17 00:00:00 2001
From: Linmiao Xu <linmiao.xu@gmail.com>
Date: Thu, 9 Apr 2026 21:47:22 +0200
Subject: [PATCH] Don't store stand pat return value in TT

Passed non-regression STC:
https://tests.stockfishchess.org/tests/view/69d2d3de61a12cebe17ede38
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 68384 W: 17646 L: 17459 D: 33279
Ptnml(0-2): 200, 8058, 17496, 8231, 207

Passed non-regression LTC:
https://tests.stockfishchess.org/tests/view/69d4293433584dad27b3c8cb
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 37290 W: 9582 L: 9380 D: 18328
Ptnml(0-2): 18, 3915, 10579, 4113, 20

closes https://github.com/official-stockfish/Stockfish/pull/6711

Bench: 2923401
---
 src/search.cpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/search.cpp b/src/search.cpp
index cc6143dd5..0214bf4d2 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1608,9 +1608,8 @@ Value Search::Worker::qsearch(Position& pos, Stack* ss, Value alpha, Value beta)
                 bestValue = (bestValue + beta) / 2;
 
             if (!ss->ttHit)
-                ttWriter.write(posKey, value_to_tt(bestValue, ss->ply), false, BOUND_LOWER,
-                               DEPTH_UNSEARCHED, Move::none(), unadjustedStaticEval,
-                               tt.generation());
+                ttWriter.write(posKey, VALUE_NONE, false, BOUND_LOWER, DEPTH_UNSEARCHED,
+                               Move::none(), unadjustedStaticEval, tt.generation());
             return bestValue;
         }