Rinse pork belly in hot water. Transfer to a cutting board and cut into 4-inch slices.
Place the pork belly, garlic, dark soy sauce, light soy sauce, salt, five-spice, black pepper, and star anise in a pot. Add enough water to cover the pork belly. Bring sauce to a boil. Reduce to a simmer and cook for about 1 hour. Continue adding water to make sure pork belly is immersed at all times.
Remove the pork belly from the sauce. Increase heat to high and stir in sugar; cook until sauce is syrupy, about 4 minutes. Reduce heat to low.
Transfer pork belly to a cutting board; cut into smaller pieces. Place back into the sauce and stir until pork belly is evenly coated.
