diff --git a/README.md b/README.md
index e8084e3..5f18265 100644
--- a/README.md
+++ b/README.md
@@ -16,11 +16,10 @@ see test-game/manifest.setage
   * [x] `input` provides case insensitive input checking
   * [x] `exact input` provides exact input checking
   * [x] `item check`, `item take` provides item checking
-* [ ] combining items and other item interactions
+* [x] combining items and other item interactions
   * [x] basic
   * [x] multiple outputs
-  * [ ] reusable items ?
-  * [ ] lockable
-    * [ ] "item" = examine an item
-    * [ ] "room" = enter a room
-    * [ ] "interactable" = use an interactable
+  * [x] lockable
+    * [x] "item" = examine an item
+    * [x] "room" = enter a room
+    * [x] "interactable" = use an interactable
diff --git a/docs.toml b/docs.toml
index 214cef5..8e2b11f 100644
--- a/docs.toml
+++ b/docs.toml
@@ -40,6 +40,8 @@ result_ids = ["id1", "id2", ...] # Required
 result_texts = ["text1", "text2", ...] # Required; short texts of the items
 # --
 text = "message when items get combined with this recipe" # Optional; default = "> You combined items."
+lock = "" # Optional; one of: item, room, interactable
+lock_target = "id" # Optional; of the lock above
 
 
 [rooms.id] # Required, id can be any other room id.
diff --git a/setage.py b/setage.py
index 3a309c4..14b095e 100755
--- a/setage.py
+++ b/setage.py
@@ -88,6 +88,8 @@ class SetageShell(Cmd):
     intro = ""
     prompt = "> "
     ruler = "~"
+    interacted_with = set()
+    rooms_been_in = set()
 
     def cmdloop(self, intro=None):
         print(self.intro)
@@ -273,6 +275,7 @@ class SetageShell(Cmd):
                       f"invalid `type` '{inter["type"]}' "
                       f"in interactable '{arg}'")
             if can_activate:
+                self.interacted_with.add(arg)
                 if "target_room" not in inter:
                     target_room = current_room_id
                 else:
@@ -431,6 +434,7 @@ class SetageShell(Cmd):
                 print(rooms[current_room_id]["go"])
             else:
                 print(f"You went {arg}.")
+            self.rooms_been_in.add(current_room_id)
         else:
             print("> I can't go there...")
         return self.check_win()
@@ -497,17 +501,34 @@ class SetageShell(Cmd):
                 return
         for recipe in recipes.items():
             rec = recipe[1]
-            # FIXME: multiple recipes with same ingredients???
-            if set(items) == set(rec["ingredients"]):
-                print(rec["text"])
-                for item in items:
-                    inventory.pop(item)
-                if "result_ids" in rec:
-                    for idx, _id in enumerate(rec["result_ids"]):
-                        inventory[_id] = rec["result_texts"][idx]
+            can = True
+            if rec["lock"]:
+                can = False
+                if rec["lock"] == "item":
+                    if rec["lock_target"] in inventory:
+                        can = True
+                elif rec["lock"] == "interactable":
+                    if rec["lock_target"] in self.interacted_with:
+                        can = True
+                elif rec["lock"] == "room":
+                    if rec["lock_target"] in self.rooms_been_in:
+                        can = True
                 else:
-                    inventory[rec["result_id"]] = rec["result_text"]
-                return
+                    print(f"ERROR: Invalid lock type for recipe `{recipe[0]}`")
+                    return True
+            if can:
+                # FIXME: multiple recipes with same ingredients???
+                if set(items) == set(rec["ingredients"]):
+                    print(rec["text"])
+                    for item in items:
+                        inventory.pop(item)
+                    if "result_ids" in rec:
+                        for idx, _id in enumerate(rec["result_ids"]):
+                            inventory[_id] = rec["result_texts"][idx]
+                    else:
+                        inventory[rec["result_id"]] = rec["result_text"]
+                    return self.check_win()
+        print("> I can't combine these...")
 
     def do_credits(self, arg):
         """Print credits."""
diff --git a/test-game/manifest.setage b/test-game/manifest.setage
index 9a9f771..d68450d 100644
--- a/test-game/manifest.setage
+++ b/test-game/manifest.setage
@@ -37,6 +37,8 @@ trash.examine = "trasshhhhhhhhhhhhh"
 
 [recipes.weapon]
 text = "ooja booja"
+lock = "item"
+lock_target = "note"
 ingredients = ["stone", "stick"]
 result_ids = ["weapon", "trash"]
 result_texts = ["a weapon", "trsh"]