diff --git a/app/controllers/Round.scala b/app/controllers/Round.scala
index 352dbfb7bb..5d0bbe3fdc 100644
--- a/app/controllers/Round.scala
+++ b/app/controllers/Round.scala
@@ -35,7 +35,7 @@ object Round extends LilaController with TheftPrevention {
   }
 
   def signedJs(gameId: String) = OpenNoCtx { req ⇒
-    JsOk(GameRepo token gameId map Env.game.gameJs.sign, CACHE_CONTROL -> "max-age=3600")
+    JsOk(fuccess(Env.game.gameJs.sign(env.hijack.tokenOf(gameId))), CACHE_CONTROL -> "max-age=3600")
   }
 
   def player(fullId: String) = Open { implicit ctx ⇒
diff --git a/modules/game/src/main/Game.scala b/modules/game/src/main/Game.scala
index ee4c97cfab..5c2d425957 100644
--- a/modules/game/src/main/Game.scala
+++ b/modules/game/src/main/Game.scala
@@ -11,7 +11,6 @@ import lila.user.User
 
 case class Game(
     id: String,
-    token: String,
     whitePlayer: Player,
     blackPlayer: Player,
     binaryPieces: ByteArray,
@@ -340,7 +339,6 @@ object Game {
   val playerIdSize = 4
   val fullIdSize = 12
   val tokenSize = 4
-  val defaultToken = "-tk-"
 
   def abandonedDate = DateTime.now - 7.days
 
@@ -356,7 +354,6 @@ object Game {
     source: Source,
     pgnImport: Option[PgnImport]): Game = Game(
     id = IdGenerator.game,
-    token = IdGenerator.token,
     whitePlayer = whitePlayer,
     blackPlayer = blackPlayer,
     binaryPieces = if (game.isStandardInit) BinaryFormat.piece.standard
@@ -387,7 +384,6 @@ object Game {
   object BSONFields {
 
     val id = "_id"
-    val token = "tk"
     val whitePlayer = "p0"
     val blackPlayer = "p1"
     val binaryPieces = "ps"
@@ -420,7 +416,6 @@ object Game {
       val nbTurns = r int turns
       Game(
         id = r str "_id",
-        token = r str "tk",
         whitePlayer = r.get[Color ⇒ Player](whitePlayer)(playerBSONHandler)(White),
         blackPlayer = r.get[Color ⇒ Player](blackPlayer)(playerBSONHandler)(Black),
         binaryPieces = r bytes binaryPieces,
@@ -448,7 +443,6 @@ object Game {
 
     def writes(w: BSON.Writer, o: Game) = BSONDocument(
       id -> o.id,
-      token -> o.token,
       whitePlayer -> ((_: Color) ⇒ o.whitePlayer),
       blackPlayer -> ((_: Color) ⇒ o.blackPlayer),
       binaryPieces -> o.binaryPieces,
diff --git a/modules/game/src/main/GameBinaryMigration.scala b/modules/game/src/main/GameBinaryMigration.scala
index 1b22ef4f8b..0a559fb531 100644
--- a/modules/game/src/main/GameBinaryMigration.scala
+++ b/modules/game/src/main/GameBinaryMigration.scala
@@ -49,7 +49,7 @@ object GameBinaryMigration {
       case (k, v) if !drops(k)             ⇒ k -> v
     })
 
-    val gameDrop = Set("c", "cc", "cs", "lm", "lmt", "p", "me", "ph", "uids")
+    val gameDrop = Set("c", "cc", "cs", "lm", "lmt", "p", "me", "ph", "uids", "tk")
     val playerDrop = Set("ps", "mts", "uid", "isOfferingDraw", "isOfferingRematch", "isProposingTakeback", "lastDrawOffer")
 
     def convertGame(o: Doc): Doc = {
diff --git a/modules/game/src/main/GameRepo.scala b/modules/game/src/main/GameRepo.scala
index 1474e8f891..c795731ad1 100644
--- a/modules/game/src/main/GameRepo.scala
+++ b/modules/game/src/main/GameRepo.scala
@@ -72,9 +72,6 @@ trait GameRepo {
     $query(Query.finished ++ Query.rated ++ Query.user(userId)) sort ($sort asc BSONFields.createdAt)
   )
 
-  def token(id: ID): Fu[String] =
-    $primitive.one($select(id), "tk")(_.asOpt[String]) map (_ | Game.defaultToken)
-
   def save(progress: Progress): Funit =
     GameDiff(progress.origin, progress.game) |> {
       case (Nil, Nil) ⇒ funit
diff --git a/modules/round/src/main/Env.scala b/modules/round/src/main/Env.scala
index 0f06924b19..5d3bd6492a 100644
--- a/modules/round/src/main/Env.scala
+++ b/modules/round/src/main/Env.scala
@@ -154,7 +154,7 @@ final class Env(
 
   private lazy val titivate = new Titivate(roundMap, meddler, scheduler)
 
-  private lazy val hijack = new Hijack(HijackTimeout, HijackEnabled)
+  lazy val hijack = new Hijack(HijackTimeout, HijackEnabled)
 
   private lazy val takebacker = new Takebacker(
     messenger = messenger,
diff --git a/modules/round/src/main/Hijack.scala b/modules/round/src/main/Hijack.scala
index d0ee83ec0e..1b4c80b666 100644
--- a/modules/round/src/main/Hijack.scala
+++ b/modules/round/src/main/Hijack.scala
@@ -1,20 +1,28 @@
 package lila.round
 
-import scala.concurrent.duration.Duration
+import scala.concurrent.duration._
 
-import lila.game.Pov
+import lila.game.{ Pov, Game, IdGenerator }
 import lila.memo.ExpireSetMemo
 import lila.user.Context
 
 private[round] final class Hijack(timeout: Duration, enabled: Boolean) {
 
+  // game ID -> game token
+  private val tokens = lila.memo.Builder.cache(
+    2 hour, 
+    (_: String) ⇒ IdGenerator.token
+  )
+
   // full game ids that have been hijacked
   private val hijacks = new ExpireSetMemo(timeout)
 
+  def tokenOf(gameId: String) = tokens get gameId
+
   def apply(pov: Pov, token: String): Boolean = enabled && {
     pov.game.rated && {
       if (hijacks get pov.fullId) true
-      else if (token != pov.game.token) {
+      else if (token != tokenOf(pov.game.id)) {
         logwarn(s"[websocket] hijacking detected ${pov.fullId}")
         hijacks put pov.fullId
         true