Byzantine Kingamon

Byzantine Kingamon is an adaptation of Backgammon for Stonehenge: An Anthology Board Game, with a couple of little twists thrown in, one of which is from Byzantine Chess. Play is nearly identical to Backgammon; however each player also has a king that move like any other piece. You must keep your king safe, though, because if your king gets captured, you lose the game. There are a few other subtle differences from Backgammon, such as requiring exact rolls in order to bear pieces off.

As is typical for Richard Hutnik's designs, there are numerous variants offered up, as well.