diff --git a/src/Hanafuda/KoiKoi/Yaku.hs b/src/Hanafuda/KoiKoi/Yaku.hs
index 2341411..712f17a 100644
--- a/src/Hanafuda/KoiKoi/Yaku.hs
+++ b/src/Hanafuda/KoiKoi/Yaku.hs
@@ -18,7 +18,7 @@ data Yaku =
   | TsukimiZake
   | HanamiZake
   | TsukiFuda
-  deriving (Eq, Ord, Show)
+  deriving (Eq, Ord, Read, Show)
 type YakuRater = Pack -> Maybe Points
 type Score = M.Map Yaku Points