From d23f96d1567aef18f49239cb36da7d98a37921b6 Mon Sep 17 00:00:00 2001
From: nodchip <nodchip@gmail.com>
Date: Sat, 6 Jun 2020 18:50:15 +0900
Subject: [PATCH] No pruning at low plies.

This makes those very early depths a bit more reliable.

Thanks, joergoster!

https://github.com/joergoster/Stockfish-NNUE/commit/be7f37187b85b8093ae0741909cbfd7b2bc76871
---
 src/search.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/search.cpp b/src/search.cpp
index fa423d6e..d03a04dd 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -950,6 +950,7 @@ moves_loop: // When in check, search starts from here
 
       // Step 14. Pruning at shallow depth (~170 Elo)
       if (  !rootNode
+          && thisThread->rootDepth > 4 * ONE_PLY
           && pos.non_pawn_material(us)
           && bestValue > VALUE_MATED_IN_MAX_PLY)
       {