Prepare the Marinade:

In a gallon-sized resealable bag, combine the soy sauce, brown sugar, pineapple juice, garlic, ginger, rice vinegar, and sesame oil. Mix thoroughly to ensure the sugar dissolves and the flavors meld. Add the chicken wings to the bag, press out excess air, and seal tightly. Place the bag in the refrigerator and allow the wings to marinate for at least 4 hours or up to 8 hours for optimal flavor infusion.

Grill the Chicken:

Preheat a grill to 375°F, setting up two zones for direct and indirect heat. Remove the wings from the marinade, reserving the liquid for later use. Position the wings on the indirect heat zone, close the lid, and cook for 5-7 minutes on each side. Continue grilling until the internal temperature reaches 145°F, ensuring even cooking.

Prepare the Teriyaki Sauce:

While the chicken is on the grill, pour the reserved marinade into a medium saucepan and bring it to a boil over medium-high heat. In a separate small bowl, whisk together the cornstarch and cool water until smooth. Gradually whisk this mixture into the boiling marinade. Stir continuously until the sauce thickens to a glossy consistency. Reserve about ½ cup of the sauce for basting the chicken; set aside the remainder for serving.

Baste and Finish the Wings:

Move the wings to the direct heat zone of the grill. Using the reserved ½ cup of teriyaki sauce, baste the wings generously. Flip the wings and baste again, allowing the sauce to caramelize. Continue grilling until the wings reach an internal temperature of 175°F and develop a rich, sticky glaze.

Rest and Serve:

Transfer the wings to a serving platter and let them rest for 5 minutes to lock in the juices. Serve immediately with the remaining teriyaki sauce on the side.