diff --git a/src/Hanafuda/Message.hs b/src/Hanafuda/Message.hs
index 4271451..5b7144e 100644
--- a/src/Hanafuda/Message.hs
+++ b/src/Hanafuda/Message.hs
@@ -76,7 +76,7 @@ data FromClient =
   | Play {move :: KoiKoi.Move, onGame :: PublicGame}
   | Quit
   | Ping
-  deriving (Generic)
+  deriving (Generic, Show)
 
 instance FromJSON FromClient
 instance ToJSON FromClient where
@@ -146,7 +146,7 @@ instance ToJSON PrivateState where
 data PublicPlayer = PublicPlayer {
       meld :: Hanafuda.Pack
     , yakus :: KoiKoi.Score
-  } deriving Generic
+  } deriving (Generic, Show)
 
 instance FromJSON PublicPlayer
 instance ToJSON PublicPlayer where
@@ -166,7 +166,7 @@ data PublicState = PublicState {
     , trick :: [Hanafuda.Card]
     , turns :: Int
     , rounds :: [(PlayerID, KoiKoi.Score)]
-  } deriving Generic
+  } deriving (Generic, Show)
 
 instance FromJSON PublicState
 instance ToJSON PublicState where
@@ -184,7 +184,7 @@ data PublicGame = PublicGame {
     , private :: ByteString
     , public :: PublicState
     , publicSignature :: ByteString
-  } deriving Generic
+  } deriving (Generic, Show)
 
 instance FromJSON PublicGame
 instance ToJSON PublicGame where