. Gather all the ingredients.
Soak bamboo skewers in water for 30 minutes.
In a small saucepan, add the mirin, soy sauce, sake, water, brown sugar, and the green part of 1 scallion, and bring it to a boil over high heat. Once boiling, reduce the heat to low and simmer, uncovered, until the liquid is reduced by half. It will take about 30 minutes. The sauce will be thicker and glossy. Let it cool to room temperature before using. Reserve 1/3 of the sauce in a small bowl for final coating.
Cut the white and light green part of scallions into 1 inch pieces.
Cut chicken into 1 inch cubes. Marinate with some salt and pepper for extra flavour.
Alternate each chicken slice with a piece of scallion lined up perpendicular to the skewer. Each skewer will hold about 4 chicken slices and 3 scallion pieces.
Grease the tray to avoid the chicken sticking on the tray. Place the skewers on top.
Set the broiler to high and wait until the heating elements are hot. Broil for 6 minutes.
After 6 minutes, brush the sauce on the meat on both sides and continue to broil for 3-4 minutes to caramelize the sauce.
Transfer the skewers to a serving plate and brush the chicken on top with the reserved sauce