Take the pickled mackerel halves (see food basics section for pickled mackerel) after removing the upper skin and taking out all bones
Put one fish halve skin side down on your board. We are going to butterfly the fish
Now with a sharp knife that you keep parallel to where the main bone had been and flat with respect to the board, cut carefully into the fish, until about a half inch of the edge of the fish. Repeat for the other section of the same halve
Then repeat the above step for the other halve
Place a piece of cling wrap on the masuki. Then place on the cling wrap one butterflied mackerel halve skin-side down and open the flaps
Place mint leaves in the centre and also the gari slices
Add a strip of cooked and 'vinegared' sushi rice (see the food basics section) in the length and an inch wide on top
Then roll the sushi tight, ensuring that most of not all of the rice is covered by fish. Make it tight by using the masuki to press the sushi roll
Leave the roll for at least 2 h before consumption, so the flavors can mingle and a delicious taste developed. Slice with a wet, sharp cooks knife rounds just before serving