In small sauce pan over low heat, combine mirin, soy sauce, honey and cook until slightly thick, about 20 minutes. Remove from the heat and let the sauce cool (it will thicken more as it cools). Place chicken thighs in a dish and brush both sides with 1-2 T of the sauce, then rub with garlic cloves. Let sit for 20 minutes. Meanwhile slice the cabbage and sauté over medium heat until slightly wilted. Set aside in bowl. Heat grill or grill pan on medium high heat. When hot, cook thighs 7-10 minutes turning occasionally until done. Place on cutting board to rest, then slice into 1/2 inch strips.
In individual serving bowls, place rice on the bottom followed by the cabbage. Then add chicken and drizzle with sauce. Garnish with the sliced scallions and toasted sesame seeds. Serve with extra sauce alongside. Serve immediately. Serves 4-6.