Bring a large pot of water to the boil. Add the pork belly and simmer for 5-8 minutes to remove impurities and tighten the skin. Remove, rinse under cold water, and pat completely dry.

Scrape the skin clean if needed. Using a skewer or sharp tool, prick the skin all over (avoid piercing into the meat). Even pricking = better crackling.

Score the meat side (not the skin). Rub with Shaoxing Wine. Combine five spice, salt and brown sugar, then massage into the meat side only.

Place pork skin-side up on a tray. Lightly brush with vinegar and refrigerate uncovered overnight to dry the skin thoroughly.

Wrap the sides and base of the pork tightly in foil, leaving the skin exposed. Cover the skin evenly with rock salt.

Preheat oven to 160° (320°F). Roast for 40 minutes.

Bring a pot of water to the boil. Blanch bok choy for 2-3 minutes until just tender. Drain well and set aside.

Remove pork from oven. Discard the rock salt and foil. Increase oven to 230° (445°F) or Grill setting and place pork on a wire rack.

Place spring onion and ginger in a heatproof bowl. Add soy sauce, dark soy, brown sugar, oyster sauce and water. Mix well.

Lightly brush the skin with oil. Return pork to oven and grill for 10-15 minutes, or until the skin is puffed and crispy. Watch closely to avoid burning!

Rest pork for 5 minutes, then chop into bite-sized pieces. Serve with blanched bok choy, steamed rice and aromatic sauce.