Hazırlanışı
1Pat the Sashimi-grade tuna dry with a paper towel. Dice the Sashimi-grade tuna into approximately 1 cm cubes.
2In a small bowl, combine the Koikuchi shoyu, Mirin, and Sake. Mix well to create the seasoning sauce.
3Open the Natto packs. If they come with individual sauce packets or karashi mustard, discard them for this recipe. Transfer the Natto into a mixing bowl.