This dish is called red-cooked pork, or hong shao rou in Mandarin. It's delicious served on steamed buns or over rice. Caramelised sugar, star anise and sherry give the braising liquid a complex flavour, and a combination of soy sauce and treacle gives the finished sauce its rich, mahogany colour. Serve on steamed buns (such as Andrea's Steamed Buns on this site).
You can use pork shoulder instead of pork belly; just shred it and discard the fat after braising.