01 - In a small saucepan, combine soy sauce, mirin, sake, sugar, garlic, and ginger. Bring to a gentle boil over medium heat, stirring until the sugar fully dissolves. Reduce heat and simmer for 5 to 7 minutes until the mixture thickens slightly. Remove from heat and let cool completely.
02 - Thread chicken pieces and scallion segments alternately onto the soaked bamboo skewers, distributing the ingredients evenly across each stick.
03 - Brush a grill or griddle pan lightly with vegetable oil and preheat over medium-high heat until the surface is hot and shimmering.
04 - Arrange the skewers on the hot grill. Cook for 3 to 4 minutes per side, brushing generously with the tare sauce as they cook, until the chicken is cooked through and develops a caramelized, glossy glaze.
05 - Transfer the yakitori to a serving platter and serve immediately while hot. Offer extra tare sauce on the side for dipping if desired.