From 9a8dd81dd7f98cbf02f16c59b4377d174d6eb4b5 Mon Sep 17 00:00:00 2001
From: Joost VandeVondele <Joost.VandeVondele@gmail.com>
Date: Sat, 11 Jul 2026 20:35:40 +0200
Subject: [PATCH] Revert "Scale Null Move Pruning reduction"

This reverts commit 9d4090e82685cca447265dcd7093d617cb34a107.

causes very poor mate finding performance, ultimately causing a CI hang on a mate in 2

Testcase:

position fen k1B5/2p5/NbN5/P7/3p4/P2p4/P1prp3/2RbK3 b - - 0 1 setoption name Hash value 16
setoption name Threads value 4
go mate 2
ucinewgame

closes https://github.com/official-stockfish/Stockfish/pull/6966

Bench: 2466447
---
 AUTHORS        | 1 -
 src/search.cpp | 4 ++--
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/AUTHORS b/AUTHORS
index 29efae747..fe573fe50 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -37,7 +37,6 @@ Aron Petkovski (fury)
 Arseniy Surkov (codedeliveryservice)
 Artem Solopiy (EntityFX)
 Auguste Pop
-Ayush (ayushthepiro11-design)
 Balazs Szilagyi
 Balint Pfliegel
 Baptiste Rech (breatn)
diff --git a/src/search.cpp b/src/search.cpp
index 3ccb4895a..0e18a8013 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -995,8 +995,8 @@ Value Search::Worker::search(
     {
         assert((ss - 1)->currentMove != Move::null());
 
-        // Null move dynamic reduction based on depth and evaluation margin
-        Depth R = 7 + depth / 3 + std::max(0, (ss->staticEval - beta) / 256);
+        // Null move dynamic reduction based on depth
+        Depth R = 7 + depth / 3;
         do_null_move(pos, st, ss);
 
         Value nullValue = -search<NonPV>(pos, ss + 1, -beta, -beta + 1, depth - R, false);