Season the Norwegian mackerel fillet with cooking wine and pepper, then let it marinate briefly.

Prepare the teriyaki sauce by mixing soy sauce, syrup, sugar, minced garlic, and water in a 2:1:1:0.5:3 ratio.

Cut the marinated mackerel into bite-sized pieces suitable for sushi topping.

Pan-fry the mackerel pieces in a lightly oiled pan until cooked, then add the teriyaki sauce and simmer. Adjust the thickness with cornstarch.

Prepare sushi rice by mixing cooked white rice with vinegar and sugar to create a sweet and tangy flavor.

Shape the sushi rice into small, round portions with slightly wet hands to prevent sticking. Add wasabi on top and place the teriyaki mackerel pieces over the rice.