Soak the wooden skewers in water for 10–20 minutes.

Combine soy sauce, water, red wine or mirin, brown sugar, and vinegar in a mixing bowl. Stir until the brown sugar dissolves.

In a large bowl, coat chicken pieces with minced garlic, ginger, ground pepper, and reserved marinade. Let marinate for at least 10 minutes.

Bring remaining marinade to a boil, thicken with cornstarch slurry, and cook until glossy.

Thread chicken onto soaked skewers, leaving space between pieces, then preheat grill or broiler.

Grill skewers for 8–12 minutes, turning occasionally and basting with thickened sauce.

Remove and rest the skewers before serving, garnished with sesame seeds or green onions if desired.