Place chicken thighs in a zip top bag
Add soy sauce, mirin or Shaoxing wine, brown sugar, apple juice, garlic, ginger and red pepper flakes to the chicken
Squeeze excess air from the bag and seal. Massage the bag so the chicken will combine with the marinade
Let sit at room temperature for 30 minutes or refrigerate for 2-3 hours
Drain the marinade and remove excess with a paper towel
Rub the chicken with 1 teaspoon of oil and grill or saute the chicken 3-4 minutes per side
Serve the grilled chicken on top of hot rice and add kimchi, cucumbers, cabbage or whatever you like to your bowl