Start by adding the Teriyaki marinade ingredients to a food storage bag along with the chicken thighs. Push out the air and seal the bag. Then massage the outside of the bag and make sure the marinade coats all of the thigh pieces.
Let the chicken marinate for at least 15 minutes and up to 24 hours.
In a small pot, mix together soy sauce, brown sugar, grated garlic, grated ginger, and cornstarch to make the teriyaki sauce.
Then heat the mixture on medium heat. Bring to a simmer, and let cook for 2-3 minutes or until the teriyaki sauce thickens enough to coat the back of a spoon. Set the teriyaki sauce aside.
Heat a large skillet on medium-high heat and add cooking oil.
Then add the marinated chicken thighs to the pan and cook for 5-6 minutes until they are golden brown.
Turn the chicken over and brown on the second side for an additional 5-6 minutes.
Next baste the thighs with the teriyaki sauce.
Then turn the chicken pieces over, and baste the back side. Let the Sauce start to brown and thicken on the outside of the chicken.
Baste and turn two times giving every piece a thick, sticky coating of sauce.
Remove the teriyaki chicken thighs from the pan and let rest for 5minutes.
Slice against the grain at 45° angle, and serve with your favorite rice and steamed vegetable combination.
Place steamed rice and vegetables on the bottom of the bowl and then add sliced chicken to the top.
Top with sesame seeds and chopped green onions for a restaurant quality dinner.