Heat water in a large wok or pan and bring it to a boil. Put the pork pieces into the water and bring to a simmer. Cook for 10 minutes, drain well, and put aside.
While the pork is cooking, in a bowl mix the soy sauce, oyster sauce, Shaoxing wine, sugar, and five spice powder. Put aside.
Turn the heat down low and cover. Cook for at least an hour, until the pork is tender.
If the sauce is runny, mix the cornstarch with one tablespoon of water and then add it to the pork mixture to thicken. If you feel the liquid is reducing too much, you can add more water as needed.
Serve with steamed rice and stir-fried greens and enjoy!