Soak bamboo skewers in water for 30 minutes to prevent burning. Cut chicken thighs into uniform 1½-inch pieces. Thread 4-5 pieces onto each skewer, leaving about 1 inch space between pieces. Alternate chicken pieces with green onion segments for added flavor.
2 lbs chicken thighs, 4 green onions, 12-16 bamboo or metal skewers
In a shallow dish, mix soy sauce, mirin, sake, sugar, minced garlic, and grated ginger. Place skewers into the marinade and turn to coat all sides. Cover and refrigerate for 30 minutes to 2 hours for best flavor without mushiness.
0.33 cup soy sauce, 0.25 cup mirin, 0.25 cup sake, 2 tbsp sugar, 3 cloves garlic, 1 tbsp fresh ginger
Preheat the grill to medium-high heat (400°F/204°C) for at least 10 minutes. Use tongs and a folded paper towel dipped in vegetable oil to oil the grates. Lightly brush chicken pieces with vegetable oil to prevent sticking during grilling.
2 tbsp vegetable oil
Grill skewers for 5-6 minutes on the first side without moving them to develop char marks. Flip skewers once and grill the other side for 5-6 minutes. During the last 3 minutes, brush the reserved marinade or boiled tare sauce onto the chicken repeatedly. The glaze should bubble and caramelize without burning.
Use an instant-read thermometer to check the thickest part of the chicken; it should reach 165°F (74°C). Remove skewers from heat and let rest for 5 minutes to allow juices to redistribute before serving.
