In a large mixing bowl, whisk together 2 cups grapefruit soda, ½ cup soy sauce, 2 tablespoons sesame oil, ½ cup brown sugar, 3 tablespoons prepared horseradish , 2 tablespoons minced garlic, and 1 tablespoon grated ginger.
Submerge 4 pounds chicken breasts or thighs into the marinade. Cover with a lid or plastic wrap and marinate the chicken for 4 hours minimum, and up to 24 hours.
When ready to cook, heat a large heavy skillet or outdoor grill to medium-high heat (about 400 degrees Fahrenheit). Remove the chicken from the marinade and cook until the chicken reaches an internal temperature of 165℉, about 6 to 8 minutes per side, depending on the size and thickness of your chicken pieces.
Let rest for 5 minutes, then slice and serve!
