1tablespoontoasted sesame seedsoptional; see Cooking Tip
Instructions
Preheat the broiler. Line a rimmed baking sheet with aluminum foil or parchment paper and spray it with nonstick cooking spray. Place 16 6-inch wooden skewers or 8 12-inch wooden skewers in a rimmed pan with water to cover and let soak for at least 20 minutes, and up to a day.
In a small saucepan combine the soy sauce, mirin, sake, oil, brown sugar, ginger and garlic. Bring the mixture to a simmer over medium-high heat, lower the heat to medium and simmer for about 3 minutes until slightly reduced and thickened. (If you are planning to marinate the chicken, let the sauce cool before the next step.)
Place the chicken in a bowl, pour over the pot of sauce and toss so that the chicken is evenly coated. Add the scallions and toss again (at this point you can marinate it for up to 8 hours).
Thread the chicken and scallions on the soaked skewers. Transfer them to the prepared baking sheet and spread out in a single layer. Broil the skewers for 4 or 5 minutes then turn using tongs, and cook for another 4 minutes or so until nicely browned and cooked through. Transfer to a serving platter or bowl. Sprinkle with the sesame seeds if using and serve with toothpicks or skewers for spearing.
Notes
To toast sesame seeds, heat them in a clean pan over medium heat for about 3 minutes, stirring frequently, until they are lightly colored and fragrant. Watch carefully so that they don't burn.