1, put cool water in the pressure cooker, put the pork elbows in and skim off the foam as it heats up.
2, when the soup is clear, add dark soy sauce, sugar, salt, cooking wine, peppercorns and dashi, and bring to a boil over high heat.
3, open the pot, cover the lid of the pressure cooker, adjust to medium heat, about 20-25 minutes or so.