Tip all of the ingredients for the ponzu sauce, except the daikon, into a sterilised jar and mix together. (The dashi stock is optional, but it softens the sauce while adding umami in the background. Use water if you don’t have dashi.) Will keep chilled for up to three months. Peel the daikon, then grate it on the finest side of the grater. Squeeze out the water and set aside in a bowl.

Rinse the sardines, then sprinkle generously with salt, especially the fins and tails, as this keeps them from burning. Skewer the sardines lengthwise, from the tail through to the head. If the sardines are already butterflied, it is better to skewer the fish in pairs using two skewers: one across the head ends and one to secure the tail ends.

Grill the sardines over a medium hot grill, about 230C – if you hold your hand 15cm above the coals, you should be able to keep it there for 3-4 seconds. (Be careful so you don’t burn your hands.) Cook on one side for 4-5 mins until the skin nearest the heat is crispy and the flesh is firm and bouncy to the touch.

Serve immediately, with a mound of grated daikon in a pool of ponzu (around 1 tbsp grated daikon to 3 tbsp ponzu). When you mix the daikon into the ponzu it will thicken, which helps it stick to the fish.