diff --git a/src/main.cpp b/src/main.cpp
index 5a32ae3d..920d9481 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -21,6 +21,7 @@
 #include <string>
 
 #include "bitboard.h"
+#include "ucioption.h"
 #include "position.h"
 #include "search.h"
 #include "thread.h"
@@ -38,6 +39,7 @@ int main(int argc, char* argv[]) {
   kpk_bitbase_init();
   Search::init();
   Threads.init();
+  TT.set_size(Options["Hash"]);
 
   cout << engine_info() << endl;
 
diff --git a/src/search.cpp b/src/search.cpp
index 03df6d78..ea777dcc 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -278,14 +278,6 @@ void Search::think() {
 
   // Read UCI options: GUI could change UCI parameters during the game
   read_evaluation_uci_options(pos.side_to_move());
-  Threads.read_uci_options();
-
-  TT.set_size(Options["Hash"]);
-  if (Options["Clear Hash"])
-  {
-      Options["Clear Hash"] = false;
-      TT.clear();
-  }
 
   UCIMultiPV = Options["MultiPV"];
   SkillLevel = Options["Skill Level"];
diff --git a/src/thread.cpp b/src/thread.cpp
index 7ffc3dfe..358ced5d 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -216,6 +216,8 @@ void ThreadsManager::set_size(int cnt) {
 
 void ThreadsManager::init() {
 
+  read_uci_options();
+
   cond_init(sleepCond);
   lock_init(splitLock);
 
diff --git a/src/ucioption.cpp b/src/ucioption.cpp
index c754353e..2f4d6f46 100644
--- a/src/ucioption.cpp
+++ b/src/ucioption.cpp
@@ -22,6 +22,7 @@
 
 #include "misc.h"
 #include "thread.h"
+#include "tt.h"
 #include "ucioption.h"
 
 using std::string;
@@ -29,6 +30,12 @@ using std::string;
 OptionsMap Options; // Global object
 
 
+/// 'On change' actions, triggered by an option's change event
+static void on_threads(UCIOption&) { Threads.read_uci_options(); }
+static void on_hash_size(UCIOption& o) { TT.set_size(o); }
+static void on_clear_hash(UCIOption& o) { TT.clear(); o = false; } // UCI button
+
+
 /// Our case insensitive less() function as required by UCI protocol
 static bool ci_less(char c1, char c2) { return tolower(c1) < tolower(c2); }
 
@@ -58,12 +65,12 @@ OptionsMap::OptionsMap() {
   o["Space"]                       = UCIOption(100, 0, 200);
   o["Aggressiveness"]              = UCIOption(100, 0, 200);
   o["Cowardice"]                   = UCIOption(100, 0, 200);
-  o["Min Split Depth"]             = UCIOption(msd, 4, 7);
-  o["Max Threads per Split Point"] = UCIOption(5, 4, 8);
+  o["Min Split Depth"]             = UCIOption(msd, 4, 7, on_threads);
+  o["Max Threads per Split Point"] = UCIOption(5, 4, 8, on_threads);
   o["Threads"]                     = UCIOption(cpus, 1, MAX_THREADS);
-  o["Use Sleeping Threads"]        = UCIOption(true);
-  o["Hash"]                        = UCIOption(32, 4, 8192);
-  o["Clear Hash"]                  = UCIOption(false, "button");
+  o["Use Sleeping Threads"]        = UCIOption(true, on_threads);
+  o["Hash"]                        = UCIOption(32, 4, 8192, on_hash_size);
+  o["Clear Hash"]                  = UCIOption(false, on_clear_hash);
   o["Ponder"]                      = UCIOption(true);
   o["OwnBook"]                     = UCIOption(true);
   o["MultiPV"]                     = UCIOption(1, 1, 500);
@@ -103,13 +110,13 @@ std::ostream& operator<<(std::ostream& os, const OptionsMap& om) {
 
 /// UCIOption class c'tors
 
-UCIOption::UCIOption(const char* v) : type("string"), min(0), max(0), idx(Options.size())
+UCIOption::UCIOption(const char* v, Fn* f) : type("string"), min(0), max(0), idx(Options.size()), on_change_action(f)
 { defaultValue = currentValue = v; }
 
-UCIOption::UCIOption(bool v, string t) : type(t), min(0), max(0), idx(Options.size())
+UCIOption::UCIOption(bool v, Fn* f) : type("check"), min(0), max(0), idx(Options.size()), on_change_action(f)
 { defaultValue = currentValue = (v ? "true" : "false"); }
 
-UCIOption::UCIOption(int v, int minv, int maxv) : type("spin"), min(minv), max(maxv), idx(Options.size())
+UCIOption::UCIOption(int v, int minv, int maxv, Fn* f) : type("spin"), min(minv), max(maxv), idx(Options.size()), on_change_action(f)
 { std::ostringstream ss; ss << v; defaultValue = currentValue = ss.str(); }
 
 
@@ -122,7 +129,12 @@ void UCIOption::operator=(const string& v) {
   assert(!type.empty());
 
   if (   !v.empty()
-      && (type == "check" || type == "button") == (v == "true" || v == "false")
+      && (type == "check") == (v == "true" || v == "false")
       && (type != "spin" || (atoi(v.c_str()) >= min && atoi(v.c_str()) <= max)))
+  {
       currentValue = v;
+
+      if (on_change_action)
+          (*on_change_action)(*this);
+  }
 }
diff --git a/src/ucioption.h b/src/ucioption.h
index f80ff86e..8150bb0b 100644
--- a/src/ucioption.h
+++ b/src/ucioption.h
@@ -29,11 +29,14 @@ struct OptionsMap;
 
 /// UCIOption class implements an option as defined by UCI protocol
 class UCIOption {
+
+  typedef void (Fn)(UCIOption&);
+
 public:
   UCIOption() {} // Required by std::map::operator[]
-  UCIOption(const char* v);
-  UCIOption(bool v, std::string type = "check");
-  UCIOption(int v, int min, int max);
+  UCIOption(const char* v, Fn* = NULL);
+  UCIOption(bool v, Fn* = NULL);
+  UCIOption(int v, int min, int max, Fn* = NULL);
 
   void operator=(const std::string& v);
   void operator=(bool v) { *this = std::string(v ? "true" : "false"); }
@@ -54,6 +57,7 @@ private:
   std::string defaultValue, currentValue, type;
   int min, max;
   size_t idx;
+  Fn* on_change_action;
 };