From: Joost VandeVondele <Joost.VandeVondele@gmail.com>
Date: Sat, 3 Nov 2018 14:03:39 +0000 (+0100)
Subject: Extension for king moves changing castling rights
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=9315ba60e68198452940a57292f27e37bc3b6ed2

Extension for king moves changing castling rights

passed STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 8463 W: 1919 L: 1747 D: 4797
http://tests.stockfishchess.org/tests/view/5be15d510ebc595e0ae2dec6

passed LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 142590 W: 23263 L: 22587 D: 96740
http://tests.stockfishchess.org/tests/view/5be1667b0ebc595e0ae2df2d

Bench: 3607243
---

diff --git a/src/search.cpp b/src/search.cpp
index c9526ec3..8a32e827 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -943,6 +943,12 @@ moves_loop: // When in check, search starts from here
                &&  pos.see_ge(move))
           extension = ONE_PLY;
 
+      // Extension for king moves that change castling rights
+      if (   type_of(movedPiece) == KING
+          && pos.can_castle(us)
+          && depth < 12 * ONE_PLY)
+          extension = ONE_PLY;
+
       // Calculate new depth for this move
       newDepth = depth - ONE_PLY + extension;