Add the soy sauce, brown sugar, honey, rice vinegar, garlic, ginger, sesame oil, and 240 ml water to a saucepan.

Whisk the cornstarch with 30 ml water in a small bowl until smooth.

Stir the cornstarch mixture into the saucepan and place over medium heat.

Cook while whisking until the sauce becomes glossy and lightly thickened.

Remove the sauce from the heat and allow it to cool completely.

Place the chicken pieces into a large bowl or resealable bag.

Pour half of the cooled sauce over the chicken and toss until evenly coated.

Refrigerate the chicken for at least 1 hour to absorb the flavors.

Reserve the remaining sauce for basting during grilling.

Thread the marinated chicken onto the skewers, leaving a little space between pieces.

Preheat the grill to medium heat and lightly oil the grates.

Arrange the skewers on the grill and cook for 4 to 5 minutes per side.

Turn the skewers regularly to promote even browning and prevent burning.

Brush the chicken with the reserved teriyaki glaze during the final minutes of cooking.

Continue grilling until the chicken reaches an internal temperature of 74°C and develops caramelized edges.

Transfer the skewers to a serving platter and let them rest for a few minutes.

Sprinkle with sesame seeds and sliced green onions before serving.