diff --git a/include/game_interface.h b/include/game_interface.h
index 515a7e7..80d8149 100644
--- a/include/game_interface.h
+++ b/include/game_interface.h
@@ -57,6 +57,9 @@ namespace Hanabi
 
     [[nodiscard]] virtual bool is_trash(const Card & card) const = 0;
 
+    /** Returns whether the card is critical, assuming it is not trash already */
+    [[nodiscard]] virtual bool is_critical(const Card & card) const = 0;
+
     [[nodiscard]] virtual bool is_playable(const Card & card) const = 0;
 
     [[nodiscard]] virtual bool is_relative_state_initialized() const = 0;
diff --git a/include/game_state.h b/include/game_state.h
index 06774d1..bb27ca3 100644
--- a/include/game_state.h
+++ b/include/game_state.h
@@ -106,6 +106,9 @@ namespace Hanabi
 
     [[nodiscard]] bool is_trash(const Card & card) const final;
 
+    /** Returns whether the card is critical, assuming that it is non-trash */
+    [[nodiscard]] bool is_critical(const Card & card) const final;
+
     [[nodiscard]] bool is_playable(const Card & card) const final;
 
     [[nodiscard]] bool is_relative_state_initialized() const final;
@@ -230,6 +233,11 @@ namespace Hanabi
     std::list<CardMultiplicity> _draw_pile{};
     std::uint8_t _endgame_turns_left{};
 
+    // This will actually not always be updated exactly, but only for those cards that are not
+    // trash yet, since for trash, this is simply not interesting.
+    // Thus, we only need to update this on discards or misplays.
+    CardArray<num_suits, int8_t> _num_copies_left {0};
+
     // further values of game state that are technically determined, but we update them anyway
     int8_t _pace{};
     uint8_t _score{};
diff --git a/include/game_state.hpp b/include/game_state.hpp
index f5b0546..9ce759f 100644
--- a/include/game_state.hpp
+++ b/include/game_state.hpp
@@ -86,6 +86,17 @@ namespace Hanabi
       incr_turn();
     }
     ASSERT(_turn == 0);
+
+    // Prepare card counting
+    CardArray<num_suits, unsigned> card_multiplicities (0);
+    for (auto const hand: _hands) {
+      for (Card const card: hand) {
+        _num_copies_left[card] += 1;
+      }
+    }
+    for (CardMultiplicity const card_mult : _draw_pile) {
+      _num_copies_left[card_mult.card] += card_mult.multiplicity;
+    }
   }
 
   template<suit_t num_suits, player_t num_players, hand_index_t hand_size>
@@ -147,6 +158,12 @@ namespace Hanabi
     return card.rank == _stacks[card.suit] - 1;
   }
 
+  template<suit_t num_suits, player_t num_players, hand_index_t hand_size>
+  bool HanabiState<num_suits, num_players, hand_size>::is_critical(Card const & card) const
+  {
+    return _num_copies_left[card] == 1;
+  }
+
   template<suit_t num_suits, player_t num_players, hand_index_t hand_size>
   std::uint64_t HanabiState<num_suits, num_players, hand_size>::enumerated_states() const
   {
@@ -186,6 +203,8 @@ namespace Hanabi
         // update clues if we played the last played_card of a stack
         _num_clues += _clues_gained_on_discard_or_stack_finished;
       }
+    } else {
+      _num_copies_left[played_card]--;
     }
 
     const unsigned long multiplicity = draw(index, cycle, !strike);
@@ -213,6 +232,8 @@ namespace Hanabi
     _num_clues += _clues_gained_on_discard_or_stack_finished;
     _pace--;
 
+    _num_copies_left[discarded_card]--;
+
     unsigned long multiplicity = draw(index, cycle, false);
     _actions_log.emplace(ActionType::discard, discarded_card, index);
 
@@ -274,6 +295,9 @@ namespace Hanabi
       for (hand_index_t index = 0; index < hand.size(); index++)
       {
         os << hand[index];
+        if (is_critical(hand[index])) {
+          os << "!";
+        }
         if (index < hand.size() - 1)
         {
           os << " ";
@@ -577,6 +601,9 @@ namespace Hanabi
     {
       _stacks[last_action.discarded.suit]++;
       _score--;
+    } else {
+      // If we misplayed, then we lost the card and have to regain it now
+      _num_copies_left[last_action.discarded]++;
     }
     check_draw_pile_integrity();
   }
@@ -597,6 +624,8 @@ namespace Hanabi
 
     _pace++;
 
+    _num_copies_left[last_action.discarded]++;
+
     revert_draw(last_action.index, last_action.discarded, cycle, false);
     check_draw_pile_integrity();
   }