diff --git a/src/Hanafuda/KoiKoi/Yaku.hs b/src/Hanafuda/KoiKoi/Yaku.hs
index e8b5502..85a1b02 100644
--- a/src/Hanafuda/KoiKoi/Yaku.hs
+++ b/src/Hanafuda/KoiKoi/Yaku.hs
@@ -25,11 +25,13 @@ data Yaku =
   | TsukiFuda
   deriving (Eq, Ord, Read, Show)
 type YakuRater = Pack -> Maybe Points
+type YakuDistance = Pack -> Int
 type Score = M.Map Yaku Points
 
 data YakuFinder = YakuFinder {
       yaku :: Yaku
     , rater :: YakuRater
+    , distance :: YakuDistance
   }
 
 instance Eq YakuFinder where
@@ -62,7 +64,11 @@ moreThan count _ pack =
 index :: (Yaku, [Card], (Pack -> YakuRater)) -> YakusByCard
 index (yaku, cards, scorer) =
   let pack = packOfCards cards in
-  let yakuFinder = YakuFinder {yaku, rater = scorer pack . intersection pack} in
+  let yakuFinder = YakuFinder {
+      yaku
+    , rater = scorer pack . intersection pack
+    , distance = size . difference pack
+  } in
   foldl (\yakusByCard card -> M.insert card (S.singleton yakuFinder) yakusByCard) M.empty cards
 
 finders :: Monthly YakusByCard