Preheat the oven to the highest temperature. Take your pork out of the fridge 30 minutes before cooking. Remove all packaging and score the skin with a sharp knife.
Rub your favourite herb and sea salt mix all over, making sure it goes inside the slits in the skin, put in a roasting tray and inside the oven.
Immediately turn the temperature down to 450F/220C. Roast for 1.5 hours until the internal temperature of the pork reads 145F/65C.
While the pork is in the oven prepare the sauce by combining water, sugar and peeled and chopped persimmons in a small saucepan, bring to a boil and let it simmer over low heat for 10 minutes until it thickens. Add chilli flakes for some heat if desired.
When the pork roast is done, cut the crackling off and slice it separately with a very sharp knife.
Serve sliced pork with warm persimmon sauce.