From c26aaf7b2a34cb97f88794c88f50a2906251c835 Mon Sep 17 00:00:00 2001
From: Bruno Dutra <brunocodutra@gmail.com>
Date: Thu, 1 Jun 2023 23:22:37 +0200
Subject: [PATCH] reduce depth on tt miss

---
 lib/search/engine.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/search/engine.rs b/lib/search/engine.rs
index afd0b6c7..baa5e137 100644
--- a/lib/search/engine.rs
+++ b/lib/search/engine.rs
@@ -166,6 +166,13 @@ impl Engine {
             };
         }
 
+        let depth = match tpos {
+            #[cfg(not(test))]
+            // Reductions are not exact.
+            None => depth - 1,
+            _ => depth,
+        };
+
         let score = match tpos {
             Some(t) => t.score().normalize(ply),
             None if ply >= depth => pos.value().cast(),