Prepare the Teriyaki Sauce: In a small container, mix 2 tablespoons of soy sauce, 2 tablespoons of mirin, 2 tablespoons of sake, and 1 tablespoon of sugar for the traditional sauce. For a non-alcoholic version, mix 2 tablespoons of soy sauce, 4 tablespoons of water, 1 tablespoon of sugar, 1 tablespoon of corn syrup, and 1/4 teaspoon of hondashi.
Prep the Chicken: Flatten 450 g of boneless skin-on chicken thighs with the back of a knife for even cooking. Pat them dry, season with salt and pepper, and lightly coat with potato starch.
Cook the Chicken: Heat 1 tablespoon of oil in a large pan over medium-high heat. Cook the chicken skin side down for about 4 minutes, then flip and cook the other side for 4-5 minutes or until cooked through. If the chicken is thick, reduce heat to medium-low and cover with a lid.
Simmer with Sauce: Wipe off excess oil from the pan, pour the teriyaki sauce over the chicken, and simmer for about 2 minutes over medium-low heat, flipping the chicken to absorb the sauce.
Serve: Remove the chicken from the pan, let it rest for a few minutes, then slice into bite-sized pieces. Serve with rice, salad greens, cherry tomatoes, and pour some leftover sauce from the pan over the chicken.