Preheat the grill to 375°F. If you use wooden skewers, soak them in water for at least 30 minutes. Gather and prepare all ingredients.
Stir together the soy sauce, brown sugar, minced garlic, and grated ginger in a medium-sized pot over medium heat.**
Bring the mixture to a simmer. Whisk 1 cup of water and cornstarch in a small bowl, then stir it into the pot. Continue whisking until the sauce thickens and turns glossy, 2-3 minutes. Let it cool before moving to the next step.
Using a ziplock bag, place the cubed chicken and ⅔ of the teriyaki sauce in the bag, about 10oz. Let it marinate for 30 minutes. Reserve the remaining ⅓ of the sauce for basting later.
Once the grill is hot, thread the chicken onto the skewers, leaving space between pieces. Grill for 4-5 minutes per side, basting with the remaining teriyaki sauce as you turn. Continue flipping until the chicken reaches 165°F, then remove from the grill.
Meanwhile, cook the rice using the remaining water and follow the directions on the container. Once the rice is done, fluff with a fork and serve with the teriyaki chicken skewers.
