1. Preparation
Cut 500g of chicken thigh into bite-sized pieces, about 2-3 cm.
Soak 8 bamboo skewers in water for at least 30 minutes to prevent burning during grilling.
Chop 2 green onions into 2-inch lengths.
In a bowl, mix together the marinade ingredients: 1/4 cup soy sauce, 1/4 cup mirin, 2 tablespoons sake, and 1 tablespoon sugar.
2. Marinating
Add the chicken pieces to the marinade and let them sit for at least 15 minutes, stirring occasionally to ensure even coating.
3. Skewering
Thread the marinated chicken pieces onto the soaked bamboo skewers, alternating with pieces of green onion. Aim for about 3-4 pieces of chicken per skewer.
4. Grilling
Preheat a grill or grill pan over medium-high heat.
Place the skewers on the grill and cook for about 5-7 minutes on each side, or until the chicken is cooked through and has nice grill marks.
During the last few minutes of grilling, brush the skewers with the leftover marinade to enhance flavor.
5. Serving
Once cooked, remove the skewers from the grill and allow them to rest for a few minutes.
Serve hot, optionally with a sprinkle of sea salt or shichimi togarashi for added flavor.