diff --git a/hanafuda-APILanguage.cabal b/hanafuda-APILanguage.cabal
index 6a54660..9cded08 100644
--- a/hanafuda-APILanguage.cabal
+++ b/hanafuda-APILanguage.cabal
@@ -23,6 +23,7 @@ library
   -- other-extensions:
   build-depends:       aeson
                      , base >=4.9 && <4.13
+                     , bytestring
                      , containers
                      , hanafuda >= 0.3.3
                      , text
diff --git a/src/Hanafuda/Message.hs b/src/Hanafuda/Message.hs
index c83b451..96350d1 100644
--- a/src/Hanafuda/Message.hs
+++ b/src/Hanafuda/Message.hs
@@ -14,22 +14,24 @@ module Hanafuda.Message (
 import Data.Char (toLower)
 import Data.Aeson (
       FromJSON(..), FromJSONKey(..), FromJSONKeyFunction(..), Options(..), SumEncoding(..), ToJSON(..), ToJSONKey(..)
-    , Value, (.:), (.=), defaultOptions, eitherDecode', encode, genericParseJSON
-    , genericToEncoding, object, pairs, withObject
+    , Value(..), (.:), (.=), defaultOptions, eitherDecode', encode, genericParseJSON
+    , genericToEncoding, object, pairs, withObject, withText
   )
 import Data.Aeson.Types (toJSONKeyText)
+import Data.ByteString (ByteString)
 import Data.Map (Map)
 import Data.Monoid ((<>))
 import Data.Text (Text)
 import qualified Data.Text as Text (pack, unpack)
+import Data.Text.Encoding (decodeUtf8, encodeUtf8)
 import GHC.Generics (Generic)
 import qualified Hanafuda (Card(..), Flower(..), Pack, cardsOfPack, empty, packOfCards)
 import Hanafuda.ID (ID(..), getID)
-import Hanafuda.KoiKoi (PlayerID, GameBlueprint(..))
+import Hanafuda.KoiKoi (PlayerID)
 import qualified Hanafuda.KoiKoi as KoiKoi (
     Action(..), Game(..), Mode(..), Move(..), Score, Source(..), Step(..), Yaku(..)
   )
-import Hanafuda.Player (Player(..), Players(..))
+import Hanafuda.Player (Player(..), Players(..), Scores)
 
 deriving instance Generic PlayerID
 instance FromJSON PlayerID
@@ -139,9 +141,41 @@ instance FromJSON Hanafuda.Flower
 instance ToJSON Hanafuda.Flower where
   toEncoding = genericToEncoding defaultOptions
 
-type PublicGame = GameBlueprint Int
+data PrivateState = PrivateState {
+      opponent :: Player KoiKoi.Score
+    , deck :: [Hanafuda.Card]
+  } deriving Generic
+
+data PublicState = PublicState {
+      mode :: KoiKoi.Mode
+    , scores :: Scores KoiKoi.Score
+    , month :: Hanafuda.Flower
+    , playing :: PlayerID
+    , winning :: PlayerID
+    , oyake :: PlayerID
+    , river :: Hanafuda.Pack
+    , step :: KoiKoi.Step
+    , trick :: [Hanafuda.Card]
+    , rounds :: [(PlayerID, KoiKoi.Score)]
+  } deriving Generic
+
+instance FromJSON PublicState
+instance ToJSON PublicState where
+  toEncoding = genericToEncoding defaultOptions
+
+instance FromJSON ByteString where
+  parseJSON = withText "ByteString" (return . encodeUtf8)
+instance ToJSON ByteString where
+  toJSON = String . decodeUtf8
+  toEncoding = toEncoding . decodeUtf8
+
+data PublicGame = PublicGame {
+      player :: Player KoiKoi.Score
+    , privateState :: ByteString
+    , publicState :: PublicState
+    , publicSignature :: ByteString
+  } deriving Generic
 
-deriving instance Generic PublicGame
 instance FromJSON PublicGame
 instance ToJSON PublicGame where
   toEncoding = genericToEncoding defaultOptions