diff --git a/src/Hanafuda/Message.hs b/src/Hanafuda/Message.hs
index bb3bd98..21429b9 100644
--- a/src/Hanafuda/Message.hs
+++ b/src/Hanafuda/Message.hs
@@ -7,6 +7,7 @@ module Hanafuda.Message (
       T(..)
     , FromClient(..)
     , PlayerStatus(..)
+    , PublicGame
     , Room
   ) where
 
@@ -23,7 +24,7 @@ import qualified Data.Text as Text (pack)
 import GHC.Generics (Generic)
 import qualified Hanafuda (Card(..))
 import Hanafuda.Key (Key(..), getKey)
-import Hanafuda.KoiKoi (PlayerKey)
+import Hanafuda.KoiKoi (PlayerKey, GameBlueprint(..))
 import qualified Hanafuda.KoiKoi as KoiKoi (Action(..), Game(..), Move(..), Source(..))
 
 deriving instance Generic PlayerKey
@@ -84,11 +85,18 @@ instance ToJSON KoiKoi.Source
 deriving instance Generic KoiKoi.Action
 instance ToJSON KoiKoi.Action
 
+type PublicGame = GameBlueprint Int
+
+deriving instance Generic PublicGame
+instance FromJSON PublicGame
+instance ToJSON PublicGame where
+  toEncoding = genericToEncoding defaultOptions
+
 data T =
     Relay {from :: PlayerKey, message :: FromClient}
   | Welcome {room :: Room, key :: PlayerKey}
   | Update {alone :: [PlayerKey], paired :: [PlayerKey]}
-  | Game {game :: Value, logs :: [KoiKoi.Action]}
+  | Game {game :: PublicGame, logs :: [KoiKoi.Action]}
   | Pong
   | Error {error :: String}
   deriving (Generic)