Whisk the soy sauce and sugar in your bowl. Add the ginger, garlic, ketchup, and pineapple juice now. Mix it until the sugar dissolves into the liquid.

Heat your large skillet over a medium-high flame. Add a small splash of oil to the hot pan. Place the chicken pieces inside the skillet carefully.

Brown the chicken on all sides for five minutes. Do not crowd the pan during this important step. Cook in batches if your skillet is too small.

Pour the prepared sauce over the browned chicken pieces. Lower the heat to a gentle and steady simmer. Let the liquid bubble for about ten minutes.

Mix cornstarch with a little water in a cup. Pour this slurry into the pan to thicken everything. Stir well until the sauce coats every piece of meat.