Rinse dried tangerine peel; Soak it in water for 3 hours; Remove it; Gently scrape off any white pith.
Rinse, drain, peel and slice ginger.
Rinse black peppercorns under running water; Drain them.
Wipe-clean tofu skin with damp kitchen paper; Tear it into few pieces.
Rinse a chicken under running water; Discard any innards and any lumps of fat from the chicken’s cavity; Remove any feather with a pair of tweezers; Rinse it under running water again; Drain it; Cut it into 4 pieces.
Hold each fresh fish firmly by the head and scrape the scales from the tail towards the gills with a fish scaler; Rinse each under running water; Insert the knife into the anus near the tail, and draw the knife toward the head, splitting each fish to the base of the gills; Spread the abdominal cavity of each with fingers; Reach in and pull out the entrails of each; Rinse the cavity of each under running water; Trim off any gills with a boning knife; Rinse each under running water again; Pat-dry the fishes with kitchen paper.
Add 4 tbsp oil and the ginger into a wok; Stir-fry it over a low heat till fragrant; Arrange the fishes into the wok; Pan-fry them over a medium heat till both sides are slightly brown; Set them aside; Turn off the heat.
Fill a stockpot with 6L water; Bring to the boil over a high heat; Add all the ingredients; Bring to the boil over a high heat again; Scoop scum off with a perforated skimmer； Turn to a medium heat; Cover the pot with its lid; Cook over a medium heat for 2 hours; Scoop scum off with the skimmer; Stir seasonings into the broth; Turn off the heat; Set a fine-mesh sieve on the top of a fat separator; Pour the broth into the separator and then transfer the broth from the fat separator into serving bowls; Ready to serve.