diff --git a/src/Hanafuda/Message.hs b/src/Hanafuda/Message.hs
index 53d369b..2f13b60 100644
--- a/src/Hanafuda/Message.hs
+++ b/src/Hanafuda/Message.hs
@@ -37,10 +37,13 @@ import qualified Hanafuda.KoiKoi as KoiKoi (
     , Score, Scores, Source(..), Step(..), Yaku(..)
   )
 import Hanafuda.Player (Player(..), Players(..))
+import Text.Read (readMaybe)
 
 instance IDType a => FromJSON (ID a) where
-  parseJSON = withText decoding (return . read . Text.unpack)
-    where decoding = let Prefix p = (prefix :: Prefix a) in p ++ "ID"
+  parseJSON = withText decoding (safeRead . Text.unpack)
+    where
+      decoding = let Prefix p = (prefix :: Prefix a) in p ++ "ID"
+      safeRead s = maybe (fail $ "Not an ID: '" ++ s ++ "'") return $ readMaybe s
 instance IDType a => FromJSONKey (ID a) where
   fromJSONKey = FromJSONKeyText (read . Text.unpack)
 instance IDType a => ToJSON (ID a) where