01 - In a mixing bowl, whisk together the soy sauce, mirin, brown sugar, honey, rice vinegar, sesame oil, minced garlic, and grated ginger until the sugar dissolves and the mixture is well combined.
02 - Measure out and reserve 3 tablespoons of the marinade in a small container; this will be used later for glazing the skewers.
03 - Place the chicken cubes in a large bowl or zip-top bag and pour the remaining marinade over the chicken. Toss to coat evenly, then refrigerate for at least 30 minutes or up to 2 hours for deeper flavor penetration.
04 - If using wooden skewers, submerge them in water for at least 30 minutes to prevent burning during cooking.
05 - Remove the chicken from the marinade, allowing excess to drip off. Thread the cubes onto skewers, leaving a small gap between pieces for even cooking.
06 - Heat a grill or broiler to medium-high, ensuring the cooking surface is hot before placing the skewers.
07 - Grill or broil the skewers for 12 to 15 minutes, turning occasionally, until the chicken is cooked through (internal temperature reaches 165°F) and lightly charred on the edges.
08 - While the skewers cook, pour the reserved marinade into a small saucepan and bring to a simmer over medium heat for 2 to 3 minutes. For a thicker glaze, stir in the cornstarch mixed with a splash of water and cook until the sauce coats the back of a spoon.
09 - Brush the cooked skewers generously with the teriyaki glaze. Garnish with toasted sesame seeds and sliced spring onions. Serve hot alongside steamed rice or grilled vegetables.