Preheat the oven to 160°C.
Add oil to a deep frying pan big enough to fit the beef shin and place on a medium-low heat.
Season the shin with salt then add to the pan. Colour on all sides until golden brown, about 5-7 minutes. Remove from the pan and reserve. Add onion, star anise and cinnamon to the pan. Sweat for about 5 minutes, then add garlic and cook for a few more minutes.
Add Shaoxing wine, scraping the bottom of the pan, then add both soy sauces, black vinegar, sugar and chilli bean paste. Bring to the boil, then simmer for 2 minutes. Add stock, bring to a simmer, then check seasoning.
Transfer the beef shin into a casserole dish or heavy-bottomed oven tray. Carefully add sauce – it should cover half to three-quarters up the shin (add a little boiling water if needed), then cover tightly with foil or a lid. Cook in the oven for 6 hours, until the beef falls off the bone easily.
Remove from the oven, allow to sit for 20 minutes. Carefully transfer the shin and sauce to a deep serving platter. Garnish with coriander and crispy-fried onions and serve.