diff --git a/BaseClasses.py b/BaseClasses.py
index 83a14058..b9d65297 100644
--- a/BaseClasses.py
+++ b/BaseClasses.py
@@ -30,8 +30,7 @@ class World(object):
         self.required_medallions = dict([(player, ['Ether', 'Quake']) for player in range(1, players + 1)])
         self._cached_entrances = None
         self._cached_locations = None
-        self._entrance_cache = {}
-        self._region_cache = {}
+        self._region_cache = {player: {} for player in range(1, players + 1)}
         self._entrance_cache = {}
         self._location_cache = {}
         self.required_locations = []
@@ -84,19 +83,23 @@ class World(object):
         self.spoiler = Spoiler(self)
         self.lamps_needed_for_dark_rooms = 1
 
-    def intialize_regions(self):
-        for region in self.regions:
+    def initialize_regions(self, regions=None):
+        for region in regions if regions else self.regions:
             region.world = self
+            self._region_cache[region.player][region.name] = region
+
+    def get_regions(self, player=None):
+        return self.regions if player is None else self._region_cache[player].values()
 
     def get_region(self, regionname, player):
         if isinstance(regionname, Region):
             return regionname
         try:
-            return self._region_cache[(regionname, player)]
+            return self._region_cache[player][regionname]
         except KeyError:
             for region in self.regions:
                 if region.name == regionname and region.player == player:
-                    self._region_cache[(regionname, player)] = region
+                    assert not region.world # this should only happen before initialization
                     return region
             raise RuntimeError('No such region %s for player %d' % (regionname, player))
 
diff --git a/InvertedRegions.py b/InvertedRegions.py
index c03e979f..61c257ff 100644
--- a/InvertedRegions.py
+++ b/InvertedRegions.py
@@ -316,7 +316,7 @@ def create_inverted_regions(world, player):
     world.shops.append(shop)
     shop.add_inventory(0, 'Bomb Upgrade (+5)', 100, 7)
     shop.add_inventory(1, 'Arrow Upgrade (+5)', 100, 7)
-    world.intialize_regions()
+    world.initialize_regions()
 
 def create_lw_region(player, name, locations=None, exits=None):
     return _create_region(player, name, RegionType.LightWorld, 'Light World', locations, exits)
diff --git a/ItemList.py b/ItemList.py
index 55eaf730..dba4a38f 100644
--- a/ItemList.py
+++ b/ItemList.py
@@ -303,7 +303,7 @@ def set_up_take_anys(world, player):
         take_any.shop.add_inventory(0, 'Blue Potion', 0, 0)
         take_any.shop.add_inventory(1, 'Boss Heart Container', 0, 0)
 
-    world.intialize_regions()
+    world.initialize_regions()
 
 def create_dynamic_shop_locations(world, player):
     for shop in world.shops:
diff --git a/Main.py b/Main.py
index b2eb57b3..32a43246 100644
--- a/Main.py
+++ b/Main.py
@@ -295,8 +295,8 @@ def copy_world(world):
 def copy_dynamic_regions_and_locations(world, ret):
     for region in world.dynamic_regions:
         new_reg = Region(region.name, region.type, region.hint_text, region.player)
-        new_reg.world = ret
         ret.regions.append(new_reg)
+        ret.initialize_regions([new_reg])
         ret.dynamic_regions.append(new_reg)
 
         # Note: ideally exits should be copied here, but the current use case (Take anys) do not require this
diff --git a/Regions.py b/Regions.py
index fed6abab..b74d399b 100644
--- a/Regions.py
+++ b/Regions.py
@@ -307,7 +307,7 @@ def create_regions(world, player):
     world.shops.append(shop)
     shop.add_inventory(0, 'Bomb Upgrade (+5)', 100, 7)
     shop.add_inventory(1, 'Arrow Upgrade (+5)', 100, 7)
-    world.intialize_regions()
+    world.initialize_regions()
 
 def create_lw_region(player, name, locations=None, exits=None):
     return _create_region(player, name, RegionType.LightWorld, 'Light World', locations, exits)