Roughly chop the green onions. Place the green onions, onion, garlic, and ginger on a baking sheet lined with foil. Place them under the broiler for 10 minutes or until nice and charred. (If you don't have a broiler, you can cook them in a dry pan.)

In a saucepan, combine the soy sauce, mirin, sake, and sugar. Add the charred vegetables. Bring it to a boil. Once it comes to a boil, reduce the heat to low. Simmer for 10 more minutes, stirring occasionally.

Once the sauce is reduced by ⅔, remove it from the heat. Set aside.

Cut the green onions into long strips. Thinly slice the cabbage. Soak them in cold water.

Prepare the chicken: Trim off any excess fat, but leave the skin on. Season both sides with salt and pepper. Coat them with some potato starch and shake off the excess.

In a pan, heat the oil over medium-low heat. Once it gets nice and hot, place the chicken, skin side down, and the green onions. Once the green onions are nice and charred, remove them from the pan.

Once you've got good color on one side, flip and cook the other side for another couple of minutes. Once the chicken is golden and crispy on both sides, reduce the heat to low. Generously brush them with teriyaki sauce. (Don't forget to coat the outside with the sauce in the pan.) Remove them from the heat and let rest before slicing.

To serve, place the drained cabbage on a plate. Add some kewpie mayo, tomato, and grilled green onions. Drizzle some of that teriyaki sauce over the cabbage. Place the teriyaki chicken on the other side. Serve it with hot rice. Enjoy~!