Kaki no Ha Zushi

Method

1. Lay the 80 g of mackerel fillet skin-side down in a shallow non-reactive dish and bury it completely under 1 tbsp of salt. Cover and refrigerate 2 hours, until the flesh has firmed and given up its water. Rinse the salt off under cold running water and pat thoroughly dry.
2. Wipe the dish clean, return the fillet and pour over 80 ml of rice vinegar with the piece of kombu. Leave 30 minutes at cool room temperature, turning once; the surface should whiten. Lift out, pat dry, then peel the fine translucent membrane off the skin starting at the head end. Slice the fillet on a long slant into 6 pieces about 5 mm thick. Discard the curing vinegar and kombu.
3. Meanwhile rinse 100 g of short-grain rice in several changes of cold water until it runs almost clear, drain in a sieve 15 minutes, then put it in a small heavy pan with 120 ml of water and soak 30 minutes. Cover, bring to the boil over medium heat, drop to the lowest heat for 12 minutes, then stand off the heat, lid on, for 10 minutes.