From 525a5749bc873a55893d8b4d4041b49ce074f407 Mon Sep 17 00:00:00 2001
From: Daniel Monroe <github.com@danielmonroe.net>
Date: Sun, 27 Jul 2025 10:06:40 -0400
Subject: [PATCH] Simplify extra continuation history updates

Passed simplification STC
LLR: 2.95 (-2.94,2.94) <-1.75,0.25>
Total: 254464 W: 65774 L: 65793 D: 122897
Ptnml(0-2): 699, 30087, 65638, 30150, 658
https://tests.stockfishchess.org/tests/view/68863283966ed85face24a59

Passed simplification LTC
LLR: 2.94 (-2.94,2.94) <-1.75,0.25>
Total: 144750 W: 37111 L: 37018 D: 70621
Ptnml(0-2): 79, 15676, 40764, 15785, 71
https://tests.stockfishchess.org/tests/view/6886655f7b562f5f7b731359

closes https://github.com/official-stockfish/Stockfish/pull/6189

Bench: 3071078
---
 src/search.cpp | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/search.cpp b/src/search.cpp
index 71a46ea7b..743f4bce7 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1856,16 +1856,13 @@ void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus) {
     static constexpr std::array<ConthistBonus, 6> conthist_bonuses = {
       {{1, 1108}, {2, 652}, {3, 273}, {4, 572}, {5, 126}, {6, 449}}};
 
-    static constexpr int conthist_offsets[6]{71, 106, -22, -20, 29, -74};
-
     for (const auto [i, weight] : conthist_bonuses)
     {
         // Only update the first 2 continuation histories if we are in check
         if (ss->inCheck && i > 2)
             break;
         if (((ss - i)->currentMove).is_ok())
-            (*(ss - i)->continuationHistory)[pc][to]
-              << (bonus * weight / 1024) + conthist_offsets[i - 1];
+            (*(ss - i)->continuationHistory)[pc][to] << (bonus * weight / 1024) + 80 * (i < 2);
     }
 }