diff --git a/game_state.h b/game_state.h
index 3544438..bfd1d88 100644
--- a/game_state.h
+++ b/game_state.h
@@ -34,8 +34,6 @@ using state_t = std::uint32_t;
 constexpr rank_t starting_card_rank = 5;
 constexpr suit_t max_suit_index = 5;
 constexpr size_t max_card_duplicity = 3;
-constexpr player_t draw_pile = -1;
-constexpr player_t trash_or_play_stack = -2;
 constexpr clue_t max_num_clues = 8;
 constexpr uint8_t not_in_starting_hand = std::numeric_limits<uint8_t>::max();
 
@@ -200,6 +198,12 @@ private:
     void incr_turn();
     void decr_turn();
 
+    static constexpr uint8_t no_endgame = std::numeric_limits<uint8_t>::max();
+    static constexpr player_t draw_pile = num_players;
+    static constexpr player_t trash_or_play_stack = num_players + 1;
+
+    std::uint64_t unique_id() const;
+
     player_t _turn{};
     clue_t _num_clues{};
     std::uint8_t _weighted_draw_pile_size{};
@@ -208,13 +212,12 @@ private:
     std::list<CardMultiplicity> _draw_pile{};
     std::uint8_t _endgame_turns_left{};
 
-    static constexpr uint8_t no_endgame = std::numeric_limits<uint8_t>::max();
-
     // This will save the card positions of all cards that are in the draw pile when we start backtracking
     CardArray<num_suits, boost::container::static_vector<player_t, max_card_duplicity>> _card_positions_draw;
 
     // This will indicate whether cards that were in hands initially still are in hands
     std::bitset<num_players * hand_size> _card_positions_hands;
+    size_t _num_useful_cards_in_starting_hands;
 
     // further statistics that we might want to keep track of
     uint8_t _pace{};
diff --git a/game_state.hpp b/game_state.hpp
index e040f01..727d8e2 100644
--- a/game_state.hpp
+++ b/game_state.hpp
@@ -69,8 +69,12 @@ namespace Hanabi {
     _hands(),
     _draw_pile(),
     _endgame_turns_left(no_endgame),
+    _card_positions_draw(),
+    _card_positions_hands(),
+    _num_useful_cards_in_starting_hands(0),
     _pace(deck.size() - 5 * num_suits - num_players * (hand_size - 1)),
-    _score(0) {
+    _score(0),
+    _enumerated_states(0) {
         std::ranges::fill(_stacks, starting_card_rank);
         for(const Card& card: deck) {
             _draw_pile.push_back({card, 1});
@@ -340,7 +344,6 @@ namespace Hanabi {
         }
 
         // Prepare cards in hands
-        uint8_t local_index_among_good_starting_hand_cards = 0;
         for(player_t player = 0; player < num_players; player++) {
             for(Card& card : _hands[player]) {
                 card.initial_trash = is_trash(card);
@@ -351,8 +354,8 @@ namespace Hanabi {
                         // This card is already in hand, so just replace the second copy by some trash
                         card = trash;
                     } else {
-                        card.local_index_among_good_starting_hand_cards = local_index_among_good_starting_hand_cards;
-                        local_index_among_good_starting_hand_cards++;
+                        card.local_index_among_good_starting_hand_cards = _num_useful_cards_in_starting_hands;
+                        _num_useful_cards_in_starting_hands++;
 
                         good_cards_in_hand.push_back(card);
                     }
@@ -360,7 +363,9 @@ namespace Hanabi {
             }
         }
         _card_positions_hands.reset();
-        _card_positions_hands.flip();
+        for(size_t i = 0; i < _num_useful_cards_in_starting_hands; i++) {
+            _card_positions_hands[i] = true;
+        }
     }
 
     template<suit_t num_suits, player_t num_players, hand_index_t hand_size>
@@ -480,4 +485,10 @@ namespace Hanabi {
         return best_probability;
     }
 
+    template<suit_t num_suits, player_t num_players, hand_index_t hand_size>
+    std::uint64_t HanabiState<num_suits, num_players, hand_size>::unique_id() const {
+        unsigned long id = _card_positions_hands.to_ulong();
+        return id;
+    }
+
 } // namespace Hanabi
\ No newline at end of file