Make the marinade by combining the soy sauce, brown sugar, Mirin (or cooking wine), water, and garlic powder. Stir until all the ingredients are properly distributed.

Place the chicken breasts in a Ziploc bag or in a bowl. Mix-in the marinade. Seal the bag and put inside the refrigerator. Marinate for at least 1 hour (overnight is better).

Heat the grill. Grill the marinated chicken for 4 to 7 minutes per side or until the internal temperature reads 165F. You can flip the chicken twice while grilling each side for half the time per rotation to avoid one side from getting burnt.

Arrange the cooked brown rice in a bowl. Put-in the grilled chicken teriyaki over the rice and top with sunny side up egg. Sprinkle some toasted sesame seeds on top of the chicken.

Serve. Share and enjoy!