Whisk soy sauce and Sherry in medium bowl to blend. Using sharp knife, make diagonal cuts at 1/2-inch intervals in duck skin (not through meat). Place duck, skin side up, in glass baking dish. Pour marinade over. Cover duck with plastic wrap and refrigerate from 2 hours to 6 hours.

Bring cherries, chicken stock, beef stock, Port and thyme sprig to boil in heavy medium saucepan over high heat. Simmer until mixture is reduced to 1/2 cup, about 15 minutes.

Meanwhile, heat heavy large skillet over medium heat. Remove duck from marinade. Add duck breasts, skin side down, to skillet. Cook until skin is crispy, about 10 minutes. Turn duck over and continue cooking to desired doneness, about 5 minutes for medium. Transfer duck to work surface slice into serving pieces. Serve covered with the sauce.

- Adapted from Bon Appetit