1 cup chicken stock (see recipe)
1/2 cup Japanese soy sauce
7 tablespoons sugar
1 tablespoon cornstarch
1 tablespoon water
2 whole boneless, skinless chicken breasts
2 tablespoons vegetable oil
Bring the stock, soy sauce and sugar to a boil in a small saucepan. Lower the heat and simmer for 2 minutes. Mix together the cornstarch and the water and whisk into the teriyaki base. Bring back to a boil and simmer for 2 more minutes. Remove from the heat. Prick holes in the chicken with the tines of a fork. Pour the sauce over the chicken breasts and marinate, turning occasionally, for 6 hours, or overnight. Heat the grill. Scrape the excess sauce off the chicken and reserve. Brush the grill with oil. Grill the chicken for 5 minutes. Turn and baste with the sauce. Continue to turn and baste, using as much sauce as desired, until the juices run clear when pricked with a knife. About 12 to 15 minutes.