Halfway through the cooking time, check the remaining amount of liquid. If it looks like there's already too little, add broth. A quarter cup should do. But check occasionally and add more as needed to make sure that the sauce does not dry out.
Lower the pork in the hot oil and brown all sides.
Pour in the dark soy sauce, light soy sauce and rice wine. Add the garlic, ginger, cinnamon stick, star anise, five-spice powder, peppercorns and about a cup of broth.
Bring to the boil, lower the heat, cover and simmer for an hour to an hour and a half or until the pork is tender.
Scoop out the pork and transfer to a cutting board. Cut into two-inch cubes.
Strain the sauce and reheat. Taste and add more light soy sauce or sugar, or both, if needed.
Add the pork cubes to the sauce. If you want eggs with your pork, now is the time to add them.
Cook the pork (and eggs) in the sauce until the sauce reduces to no more than a couple of tablespoonfuls.
Transfer the meat and sauce (and eggs) to a serving bowl. Sprinkle with cilantro (or scallions) and serve hot.