diff --git a/src/Automaton.hs b/src/Automaton.hs
index b0fad58..9809e68 100644
--- a/src/Automaton.hs
+++ b/src/Automaton.hs
@@ -10,13 +10,13 @@ import Data.Aeson (encode, eitherDecode')
 import Data.ByteString.Lazy.Char8 (ByteString, append, pack, putStrLn)
 import qualified Data.ByteString.Lazy.Char8 as ByteString (concat)
 import Data.Map ((!))
-import qualified Data.Map as Map (delete, empty, member)
+import qualified Data.Map as Map (delete, empty, lookup)
 import Control.Monad.Reader (ReaderT, ask)
 import Control.Monad.Trans (lift)
 import Hanafuda.KoiKoi (Step(..))
-import Hanafuda.Message (Coordinates(..), FromClient(..), T(..), orderCoordinates)
+import Hanafuda.Message (FromClient(..), T(..), orderCoordinates)
 import qualified Hanafuda.Message as Message (
-    T(..), FromClient, PublicGame(..), PublicState(..)
+    Coordinates(..), FromClient, PublicGame(..), PublicState(..), T(..)
   )
 import Network.WebSockets (Connection, receiveData, sendTextData)
 import Prelude hiding (error, putStrLn)
@@ -58,16 +58,14 @@ answer (Message.Relay {Message.from, Message.message = Message.LogIn {Message.na
   | from == key = return $ LoggedIn {key, name}
 -}
 
-answer state@(Connected {games}) (Relay {from, message = Invitation {}}) =
-  -- policy : one game per player only
-  send (Answer {accept = not $ Map.member from games, to = from})
-  >> return state
+answer state@(Connected {}) (Relay {from, message = Invitation {}}) =
+  send (Answer {accept = True, to = from}) >> return state
 
 answer state@(Connected {playerID, games}) message@(Game {}) = do
   case Message.step $ Message.public game of
     Over ->
-      let opponentID = Message.nextPlayer (Message.public game) ! playerID in
-      return $ state {games = Map.delete opponentID games}
+      let xGameID = Message.gameID . Message.coordinates $ Message.public game in
+      return $ state {games = Map.delete xGameID games}
     _ ->
       if Message.playing (Message.public game) == playerID
       then
@@ -82,21 +80,21 @@ answer state (Error {error}) = do
   debug $ "Received error from server : " `append` pack error
   return state
 
-answer state@(Connected {games}) (Relay {from, message = Sync {latestKnown}})
-  | not $ Map.member from games =
-      send (Yield {onGameID = gameID latestKnown, to = from}) >> return state
-  | otherwise =
-    case orderCoordinates latestKnownHere latestKnown of
-      Just LT -> send $ Yield {onGameID = gameID latestKnown, to = from}
-      Just GT -> send $ Share {gameSave = game}
-      _ -> return ()
-    >> return state
-    where
-      game = games ! from
-      latestKnownHere = Message.coordinates $ Message.public game
+answer state@(Connected {games}) (Relay {from, message = Sync {latestKnown}}) =
+  case Map.lookup gameID games of
+    Nothing -> send $ Yield {onGameID = gameID, to = from}
+    Just game ->
+      let latestKnownHere = Message.coordinates $ Message.public game in
+      case orderCoordinates latestKnown latestKnownHere of
+        Just LT -> send $ Share {gameSave = game}
+        Just GT -> send $ Yield {onGameID = gameID, to = from}
+        _ -> return ()
+  >> return state
+  where
+    gameID = Message.gameID latestKnown
 
-answer state@(Connected {games}) (Relay {from, message = Yield {}}) =
-  send (Share {gameSave = games ! from}) >> return state
+answer state@(Connected {games}) (Relay {message = Yield {onGameID}}) =
+  send (Share {gameSave = games ! onGameID}) >> return state
 
 {-
  - Ignore
diff --git a/src/Session.hs b/src/Session.hs
index fce1782..4f76cbf 100644
--- a/src/Session.hs
+++ b/src/Session.hs
@@ -8,7 +8,7 @@ module Session (
 import Config (libDir)
 import Data.Map (Map)
 import qualified Data.Map as Map (empty)
-import Hanafuda.KoiKoi (PlayerID)
+import Hanafuda.KoiKoi (GameID, PlayerID)
 import qualified Hanafuda.Message as Message (PublicGame)
 import System.Directory (createDirectoryIfMissing, doesFileExist)
 import System.FilePath ((</>))
@@ -17,7 +17,7 @@ data State =
     New
   | Connected {
         playerID :: PlayerID
-      , games :: Map PlayerID Message.PublicGame
+      , games :: Map GameID Message.PublicGame
     }
   deriving Show