diff --git a/src/position.cpp b/src/position.cpp
index fd7b1ba26a0..c26ab1b6884 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -700,14 +700,6 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
   // Copy some fields of old state to our new StateInfo object except the ones
   // which are recalculated from scratch anyway, then switch our state pointer
   // to point to the new, ready to be updated, state.
-  struct ReducedStateInfo {
-    Key pawnKey, materialKey;
-    Value npMaterial[2];
-    int castleRights, rule50, pliesFromNull;
-    Score psq_score;
-    Square epSquare;
-  };
-
   memcpy(&newSt, st, sizeof(ReducedStateInfo));
 
   newSt.previous = st;
diff --git a/src/position.h b/src/position.h
index 6351f580035..55dc33feee9 100644
--- a/src/position.h
+++ b/src/position.h
@@ -60,6 +60,14 @@ struct StateInfo {
   StateInfo* previous;
 };
 
+struct ReducedStateInfo {
+  Key pawnKey, materialKey;
+  Value npMaterial[2];
+  int castleRights, rule50, pliesFromNull;
+  Score psqScore;
+  Square epSquare;
+};
+
 
 /// The position data structure. A position consists of the following data:
 ///