1. Soak the bamboo skewers in water for 30 minutes.

Yakitori Sauce (Tare)

1. In a small saucepan, mix together the mirin, soy sauce, sake, water, brown sugar and the green part of 1 spring onion. Bring it to a boil over high heat. When it starts to boil, decrease the heat to low and simmer, uncovered, until the liquid is reduced by half. It will take about 30 minutes.
   
2. Let it cool to room temperature before using. Reserve ⅓ of the sauce in a small bowl for the final coating.

Yakitori

1. Cut the white and light green part of scallions into 2.5 cm - 1 inch pieces.
2. Cut chicken into 2.5 cm - 1 inch cubes.
3. Insert the chicken at a 45 degrees angle into the skewers.
4. Alternate each chicken slice with a piece of spring onion.
5. Grease the grate of the broiler/wire rack (or oven-safe cooling rack) to prevent the chicken from sticking. Place the skewers on top.
6. Set the broiler to high and wait until the heating elements are hot. Broil for 6 minutes.
   
7. After 6 minutes, brush the sauce onto the meat on both sides and continue to broil for 3-4 minutes or until cooked through and to caramelize the sauce.
8. Transfer the skewers to a serving plate and brush the chicken with the reserved sauce with a clean brush. (Make sure that the sauce for the final coating does not come in contact with the raw chicken or you will have to boil the sauce again to avoid contamination.  Also, use a clean brush for the final coating!).
9. Serve warm.