diff --git a/include/riichi.hrl b/include/riichi.hrl
index 40a4ead..add7414 100644
--- a/include/riichi.hrl
+++ b/include/riichi.hrl
@@ -1,21 +1,21 @@
+-type wind()   :: east | south | west | north.
+-type dragon() :: green | red | white.
+
 -record(tile, {
-    suit,
-    value
+          suit       :: pin | man | sou | wind | dragon,
+          value      :: integer() | wind() | dragon(),
+          from=draw  :: draw | wind()
 }).
+-type tile() :: #tile{}.
+
+-record(meld, {
+          type  :: pair | chii | pon | kan,
+          tiles :: [tile()]
+}).
+-type meld() :: #meld{}.
 
 -record(hand, {
-    tiles=[],
-    sets=[],
-    seqs=[]
-}).
-
--record(set, {
-    count,
-    tile,
-    open=true
-}).
-
--record(seq, {
-    tiles,
-    open=true
+          tiles=[] :: [tile()],
+          melds=[] :: [meld()]
 }).
+-type hand() :: #hand{}.
diff --git a/src/riichi_hand.erl b/src/riichi_hand.erl
index 5e37c88..445b37d 100644
--- a/src/riichi_hand.erl
+++ b/src/riichi_hand.erl
@@ -10,21 +10,16 @@ find(Tiles) ->
 find([], Hand, Possible) ->
     [Hand|Possible];
 
-find(Tiles, Hand = #hand{tiles=HT, sets=HS}, Possible) ->
-    case Tiles of
-        [T, T, T, T|Rest] ->
-            find(Rest, Hand#hand{sets=[#set{count=4, tile=T, open=false}|HS]}, Possible);
-        _ -> []
-    end ++
+find(Tiles, Hand = #hand{tiles=HT, melds=HM}, Possible) ->
     case Tiles of
         [T, T, T|Rest] ->
-            find(Rest, Hand#hand{sets=[#set{count=3, tile=T, open=false}|HS]}, Possible);
+            find(Rest, Hand#hand{melds=[#meld{type=pon, tiles=[T, T, T]}|HM]}, Possible);
         _ ->
             []
     end ++
     case Tiles of
         [T, T|Rest] ->
-            find(Rest, Hand#hand{sets=[#set{count=2, tile=T, open=false}|HS]}, Possible);
+            find(Rest, Hand#hand{melds=[#meld{type=pair, tiles=[T, T]}|HM]}, Possible);
         _ ->
             []
     end ++
@@ -32,7 +27,7 @@ find(Tiles, Hand = #hand{tiles=HT, sets=HS}, Possible) ->
         [T1 = #tile{value=V1, suit=S}, T2 = #tile{value=V2, suit=S}, T3 = #tile{value=V3, suit=S}|_] when
               is_integer(V1) andalso
               [V1, V2, V3] =:= [V1, V1 + 1, V1 + 2] ->
-            find(Tiles -- [T1, T2, T3], Hand#hand{sets=[#seq{tiles=[T1, T2, T3], open=false}|HS]}, Possible);
+            find(Tiles -- [T1, T2, T3], Hand#hand{melds=[#meld{type=chii, tiles=[T1, T2, T3]}|HM]}, Possible);
         _ ->
             []
     end ++
@@ -41,12 +36,12 @@ find(Tiles, Hand = #hand{tiles=HT, sets=HS}, Possible) ->
             find(Rest, Hand#hand{tiles=[T|HT]}, Possible)
     end.
 
-is_complete(#hand{tiles=[], sets=Sets}) ->
-    Pairs = [S || S <- Sets, S#set.count =:= 2],
+is_complete(#hand{tiles=[], melds=Melds}) ->
+    Pairs = [M || M <- Melds, M#meld.type =:= pair],
     case length(Pairs) of
         1 ->
             % Four mentsu + 1 pair = 5 sets
-            length(Sets) =:= 5;
+            length(Melds) =:= 5;
         7 ->
             % Must be seven *unique* pairs
             sets:size(sets:from_list(Pairs)) =:= 7;
@@ -57,9 +52,9 @@ is_complete(#hand{}=Hand) ->
     kokushi_musou(Hand).
 
 % 13 Orphans
-kokushi_musou(#hand{tiles=Tiles, sets=Sets}) when
+kokushi_musou(#hand{tiles=Tiles, melds=Melds}) when
       length(Tiles) =:= 13
-      andalso length(Sets) =:= 0 ->
+      andalso length(Melds) =:= 0 ->
     not lists:any(fun(#tile{value=V}) ->
                           lists:member(V, lists:seq(2,8))
                   end,
diff --git a/src/yaku.erl b/src/yaku.erl
index 79aaeb0..f742c7a 100644
--- a/src/yaku.erl
+++ b/src/yaku.erl
@@ -5,21 +5,23 @@
 -compile([export_all]).
 
 
-yakuhai(#hand{sets=Sets}) ->
-    length(lists:filter(fun(T = #tile{}) ->
-                                case T#tile.suit of
-                                    wind ->
+yakuhai(#hand{melds=Melds}) ->
+    length(lists:filter(fun(#meld{type=Type, tiles=[T|_]}) ->
+                                case {Type, T} of
+                                    {pair, _} ->
+                                        false;
+                                    {chii, _} ->
+                                        false;
+                                    {_, #tile{suit=wind}} ->
                                         % TODO: Round/Seat Winds
                                         false;
-                                    dragon ->
-                                        true;
-                                    _ ->
-                                        false
+                                    {_, #tile{suit=dragon}} ->
+                                        true
                                 end
                         end,
-                        Sets)).
+                        Melds)).
 
-tanyao(#hand{sets=Sets}) ->
+tanyao(#hand{melds=Melds}) ->
     not lists:any(fun(T = #tile{}) ->
                           case T#tile.suit of
                               dragon ->
@@ -30,32 +32,22 @@ tanyao(#hand{sets=Sets}) ->
                                   lists:member(T#tile.value, [1,9])
                           end
                   end,
-                  Sets).
+                  lists:flatten([Tiles || #meld{tiles=Tiles} <- Melds])).
 
-pinfu(#hand{sets=Sets}) ->
+pinfu(#hand{melds=Melds}) ->
     % TODO: Verify closed, open wait, pair not round/seat wind
-    lists:all(fun(S) ->
-                      case S of
-                          #seq{} ->
-                              true;
-                          _ ->
-                              false
-                      end
-              end,
-              [S || S <- Sets]).
+    length([M || M = #meld{type=T} <- Melds, T =:= chii]) =:= 4.
 
 % 7 Pairs
-chiitoitsu(#hand{tiles=[], sets=Sets})
-  when length(Sets) =:= 7 ->
-    Pairs = [S || S <- Sets, S#set.count =:= 2],
+chiitoitsu(#hand{tiles=[], melds=Melds})
+  when length(Melds) =:= 7 ->
+    Pairs = [S || S <- Melds, S#meld.type =:= pair],
     length(Pairs) =:= 7 andalso sets:size(sets:from_list(Pairs)) =:= 7.
 
 % 13 Orphans
-kokushi_musou(#hand{tiles=Tiles, sets=Sets})
-  when length(Tiles) =:= 13
-       andalso length(Sets) =:= 0 ->
+kokushi_musou(#hand{tiles=Tiles, melds=[#meld{type=pair, tiles=[T,T]}]}) ->
     not lists:any(fun(#tile{value=V}) ->
                           lists:member(V, lists:seq(2,8))
                   end,
-                  Tiles)
-        andalso sets:size(sets:from_list(Tiles)) =:= 13.
+                  [T|Tiles])
+        andalso sets:size(sets:from_list([T|Tiles])) =:= 13.