Rinse cold rice with boiled water. Drain and set aside.
Rinse dong cai. Squeeze dry. Mix marinade ingredients with minced pork. Leave for 15 minutes. Soak fish flakes in water till soft. Set aside.
Wash oysters with 2 tbsp corn starch. Rinse well. Marinade for 15 minutes. Scald in boiling water with ginger slices for a while. Remove from water and rinse. Drain and set aside.
Boil chicken stock. Add minced pork. Mix well till pork is done. Add oysters, cold rice, diced celery, fish flakes and dong cai. Bring it to boil. Sprinkle spring onion and coriander on top. Serve.