diff --git a/src/benchmark.cpp b/src/benchmark.cpp
index c3a41913..9dc103ed 100644
--- a/src/benchmark.cpp
+++ b/src/benchmark.cpp
@@ -110,6 +110,7 @@ void benchmark(const Position& current, istream& is) {
   }
 
   int64_t nodes = 0;
+  Search::StateStackPtr st;
   Time time = Time::current_time();
 
   for (size_t i = 0; i < fens.size(); i++)
@@ -126,7 +127,7 @@ void benchmark(const Position& current, istream& is) {
       }
       else
       {
-          Threads.start_searching(pos, limits, vector<Move>());
+          Threads.start_searching(pos, limits, vector<Move>(), st);
           Threads.wait_for_search_finished();
           nodes += Search::RootPosition.nodes_searched();
       }
diff --git a/src/search.cpp b/src/search.cpp
index b86b9559..3309947e 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -43,6 +43,7 @@ namespace Search {
   std::vector<RootMove> RootMoves;
   Position RootPosition;
   Time SearchTime;
+  StateStackPtr SetupStates;
 }
 
 using std::string;
diff --git a/src/search.h b/src/search.h
index d580b546..63b9b326 100644
--- a/src/search.h
+++ b/src/search.h
@@ -21,12 +21,14 @@
 #define SEARCH_H_INCLUDED
 
 #include <cstring>
+#include <memory>
+#include <stack>
 #include <vector>
 
 #include "misc.h"
+#include "position.h"
 #include "types.h"
 
-class Position;
 struct SplitPoint;
 
 namespace Search {
@@ -91,11 +93,14 @@ struct SignalsType {
   bool stopOnPonderhit, firstRootMove, stop, failedLowAtRoot;
 };
 
+typedef std::auto_ptr<std::stack<StateInfo> > StateStackPtr;
+
 extern volatile SignalsType Signals;
 extern LimitsType Limits;
 extern std::vector<RootMove> RootMoves;
 extern Position RootPosition;
 extern Time SearchTime;
+extern StateStackPtr SetupStates;
 
 extern void init();
 extern size_t perft(Position& pos, Depth depth);
diff --git a/src/thread.cpp b/src/thread.cpp
index ce2f41f2..541610a1 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -414,7 +414,7 @@ void ThreadPool::wait_for_search_finished() {
 // a new search, then returns immediately.
 
 void ThreadPool::start_searching(const Position& pos, const LimitsType& limits,
-                                 const std::vector<Move>& searchMoves) {
+                                 const std::vector<Move>& searchMoves, StateStackPtr& states) {
   wait_for_search_finished();
 
   SearchTime.restart(); // As early as possible
@@ -424,6 +424,7 @@ void ThreadPool::start_searching(const Position& pos, const LimitsType& limits,
 
   RootPosition = pos;
   Limits = limits;
+  SetupStates = states; // Ownership transfer here
   RootMoves.clear();
 
   for (MoveList<LEGAL> ml(pos); !ml.end(); ++ml)
diff --git a/src/thread.h b/src/thread.h
index 5feab000..6a929a98 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -145,8 +145,8 @@ public:
   bool available_slave_exists(Thread* master) const;
   void set_timer(int msec);
   void wait_for_search_finished();
-  void start_searching(const Position& pos, const Search::LimitsType& limits,
-                       const std::vector<Move>& searchMoves);
+  void start_searching(const Position&, const Search::LimitsType&,
+                       const std::vector<Move>&, Search::StateStackPtr&);
 
   template <bool Fake>
   Value split(Position& pos, Search::Stack* ss, Value alpha, Value beta, Value bestValue, Move* bestMove,
diff --git a/src/uci.cpp b/src/uci.cpp
index ac58b43c..31d0a721 100644
--- a/src/uci.cpp
+++ b/src/uci.cpp
@@ -17,7 +17,6 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include <deque>
 #include <iostream>
 #include <sstream>
 #include <string>
@@ -39,6 +38,10 @@ namespace {
   // FEN string of the initial position, normal chess
   const char* StartFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
 
+  // Keep track of position keys along the setup moves (from start position to the
+  // position just before to start searching). Needed by repetition draw detection.
+  Search::StateStackPtr SetupStates;
+
   void set_option(istringstream& up);
   void set_position(Position& pos, istringstream& up);
   void go(Position& pos, istringstream& up);
@@ -155,10 +158,6 @@ namespace {
 
   void set_position(Position& pos, istringstream& is) {
 
-    // Keep track of position keys along the setup moves (from start position to the
-    // position just before to start searching). Needed by repetition draw detection.
-    static std::deque<StateInfo> st;
-
     Move m;
     string token, fen;
 
@@ -176,13 +175,13 @@ namespace {
         return;
 
     pos.from_fen(fen, Options["UCI_Chess960"], Threads.main_thread());
-    st.clear();
+    SetupStates = Search::StateStackPtr(new std::stack<StateInfo>());
 
     // Parse move list (if any)
     while (is >> token && (m = move_from_uci(pos, token)) != MOVE_NONE)
     {
-        st.push_back(StateInfo());
-        pos.do_move(m, st.back());
+        SetupStates->push(StateInfo());
+        pos.do_move(m, SetupStates->top());
     }
   }
 
@@ -248,6 +247,6 @@ namespace {
                 searchMoves.push_back(move_from_uci(pos, token));
     }
 
-    Threads.start_searching(pos, limits, searchMoves);
+    Threads.start_searching(pos, limits, searchMoves, SetupStates);
   }
 }