Cut pork belly into 1/2inch strips. In a large bowl, combine pork belly, salt, pepper, garlic, sugar, and shoyu. Mix well.
Cover the bowl with plastic wrap and place in refrigerator to marinate overnight or for at least 1hour.
Once the pork belly has finished marinating, in a small bowl, mix ketchup and oil. Reserve for basting.
Preheat grill to med-high heat.
Once grill is ready, place pork belly down and cook for 6-8 minutes on each side, basting the top of the poke belly after flipping it over.
Cook until internal temperature reaches 165°F or desired doneness.
Transfer to plate and serve.