In a large bowl whisk together 1 cup of soy sauce, 1 cup of red wine, 1 cup of red wine vinegar, diced shallots and minced garlic until combined.
Next, lay the chicken flat in a 13x9 dish and pour the marinade all over it. Cover and refrigerate for 24 hours. After 12 hours flip the chicken over to make sure the marinade gets on all sides.
Remove the chicken from liquid and season on all sides with salt and pepper.
Cook the chicken on a medium-hot grill, 450°, for a total of 45 to 50 minutes. The chicken should be cooked through with an internal temperature of 165°. Rest the chicken on a cutting board before serving.
Pour the remaining soy, red wine and red vinegar into a sauce pot and heat up over low heat until steam is lightly coming off of it. Stir in the butter and green onions and serve over top or on the side of the grilled chicken.