Mix teriyaki sauce - Add soy sauce, sake, mirin, and sugar in a bowl. Use a grater to grate the ginger into the mixture and whisk until well mixed. Set aside.
3 tablespoon soy sauce, 1 tablespoon sake, 4 tablespoon mirin, 2 teaspoon brown sugar, 1 small ginger knob
Tenderize and season chicken - Tenderize the chicken so they are the same thickness. Generously season on both sides with salt, pepper, and garlic powder.
4 boneless, skin-on chicken thighs, kosher salt, freshly ground black pepper, 1 tablespoon garlic powder
Cook chicken - In a large skillet over medium heat, add oil. Once the oil is hot, use tongs to place the chicken skin side down. Use the tongs to gently push down on the meat so all of the skin comes into contact with the pan and cooks evenly. Cook for 5-7 minutes until the skin turns golden. Then turn the chicken thighs over, add a tablespoon of water to the pan, and cover with a lid. Cook for an additional 8-10 minutes or until the internal temperature reaches 165°F in the thickest part.
1 tablespoon neutral cooking oil
Simmer in sauce - Reduce the heat to low, then pour the teriyaki marinade over the chicken. Cook for an additional 2 minutes to reduce the sauce, baste the chicken with the sauce, then remove from heat.
Cut chicken and assemble - Place the chicken on a cutting board and slice into strips. Divide rice into bowls, place the chicken on top of the rice, and drizzle with the teriyaki sauce from the pan. Sprinkle the chicken with sesame seeds and green onions.
sesame seeds, 2 green onions