diff --git a/src/game_state.cpp b/src/game_state.cpp
new file mode 100644
index 0000000..4c5333f
--- /dev/null
+++ b/src/game_state.cpp
@@ -0,0 +1,60 @@
+#include "game_state.h"
+
+namespace Hanabi {
+
+  void Game::make_turn()
+  {
+    assert(next_action < actions.size());
+    Card const next_draw = deck[deck.size() - state->draw_pile_size()];
+    state->rotate_next_draw(next_draw);
+    Action const & action = actions[next_action];
+    std::uint8_t index;
+    switch(action.type) {
+      case Hanabi::ActionType::color_clue:
+      case Hanabi::ActionType::rank_clue:
+        state->give_clue();
+        break;
+      case Hanabi::ActionType::discard:
+        index = state->find_card_in_hand(action.card);
+        ASSERT(index != std::uint8_t(-1));
+        state->discard(index);
+        break;
+      case Hanabi::ActionType::play:
+        index = state->find_card_in_hand(action.card);
+        ASSERT(index != std::uint8_t(-1));
+        state->play(index);
+        break;
+      case Hanabi::ActionType::vote_terminate_players:
+      case Hanabi::ActionType::vote_terminate:
+      case Hanabi::ActionType::end_game:
+        ;
+    }
+    ++next_action;
+  }
+
+  void Game::revert_turn()
+  {
+    state->revert();
+  }
+
+  void Game::forward_until(size_t turn, size_t draw_pile_break)
+  {
+    for (size_t i = 0; i < std::min(turn - 1, actions.size()); i++) {
+      if (state->draw_pile_size() == draw_pile_break) {
+        break;
+      }
+      make_turn();
+    }
+  }
+
+  void Game::revert_until(size_t draw_pile_break)
+  {
+    while(state->draw_pile_size() < draw_pile_break) {
+      revert_turn();
+    }
+    while(state->last_action_type() == ActionType::clue)
+    {
+      revert_turn();
+    }
+  }
+}