From 035165299526cfd6d97cbe71c1220a4e9a7a8cce Mon Sep 17 00:00:00 2001
From: Shawn Xu <xu107288696@gmail.com>
Date: Sun, 19 Oct 2025 17:11:36 -0700
Subject: [PATCH] Simplify Pawn History Bonus

Passed Non-regression STC:
LLR: 2.98 (-2.94,2.94) <-1.75,0.25>
Total: 122016 W: 31655 L: 31525 D: 58836
Ptnml(0-2): 388, 14317, 31474, 14435, 394
https://tests.stockfishchess.org/tests/view/68f57e66637acd2a11e7221d

Passed Non-regression LTC:
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 81348 W: 21016 L: 20858 D: 39474
Ptnml(0-2): 45, 8793, 22841, 8949, 46
https://tests.stockfishchess.org/tests/view/68f9e2d9637acd2a11e72997

closes https://github.com/official-stockfish/Stockfish/pull/6382

Bench: 2370893
---
 src/search.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/search.cpp b/src/search.cpp
index b9321de75..4a55da301 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1869,7 +1869,7 @@ void update_quiet_histories(
 
     int pIndex = pawn_history_index(pos);
     workerThread.pawnHistory[pIndex][pos.moved_piece(move)][move.to_sq()]
-      << (bonus * (bonus > 0 ? 800 : 500) / 1024) + 70;
+      << bonus * (bonus > 0 ? 850 : 550) / 1024;
 }
 
 }