In a bowl, whisk together soy sauce, honey, brown sugar, garlic, ginger, rice vinegar, and sesame oil.
Add chicken thighs and coat well. Cover and marinate for at least 1 hour (or overnight).
Oven Method:
Preheat oven to 200°C (400°F).
Place chicken on a lined baking sheet and bake for 25–30 minutes, basting halfway through.
Slow Cooker Method:
Place chicken and marinade in slow cooker. Cook on LOW for 6 hours or HIGH for 3–4 hours.
Grill Method:
Preheat grill to medium heat and cook chicken for 20–25 minutes, turning and basting regularly.
Optional: Mix cornstarch with water and simmer leftover marinade until thickened, then brush over cooked chicken.
Serve warm with your favorite sides.