ingredients:

Tuna . .100g
Special soy sauce
(Combine 7 parts soy sauce and 3 parts sake and let stand in a pot. Put a pack of dried bonito flakes in it and leave it until it cools down.
Strain the dried bonito flakes and serve. (The leftover dried bonito flakes can be mixed with ground sesame seeds in a pot to make furikake (sprinkled on rice).
Wasabi (Japanese horseradish) - to taste