diff --git a/bdr.py b/bdr.py
new file mode 100644
index 0000000..b19c512
--- /dev/null
+++ b/bdr.py
@@ -0,0 +1,28 @@
+from typing import List, Dict
+
+from hanabi.hanab_game import Action, ActionType
+from hanabi.live.hanab_live import HanabLiveInstance, parse_json_game, HanabLiveGameState
+
+
+def get_bdrs(instance: HanabLiveInstance, actions: List[Action]) -> List[int]:
+    bdrs = []
+    game = HanabLiveGameState(instance)
+    for action in actions:
+        if action.type == ActionType.Discard:
+            discard = instance.deck[action.target]
+            if not game.is_trash(discard):
+                if discard.rank != 1:
+                    if discard in game.deck[game.progress:]:
+                        bdrs.append(game.draw_pile_size)
+                else:
+                    if game.deck[game.progress:].count(discard) == 2:
+                        bdrs.append(game.draw_pile_size)
+        game.make_action(action)
+    return bdrs
+
+
+def describe_game(game_json: Dict):
+    instance, actions = parse_json_game(game_json)
+    bdrs = get_bdrs(instance, actions)
+    return bdrs
+