Negitoro and Tekka Maki Fatty Tuna Preparations

Ingredients

• For the negitoro
• 300 g tuna carcass (backbone, collar bones, skeletal surfaces), bone-adjacent fatty meat to be scraped; do not discard after filleting
• 20 g negi (spring onion), finely and uniformly minced
• 5 ml sesame oil, use sparingly; a few drops too many creates a greasy result
• 5 ml soy sauce
• 5 g fresh ginger, finely grated
• For the tekka maki
• 150 g akami (lean red tuna loin), sliced against the grain of the muscle fibre into rectangular strips
• For the shari (vinegared rice)
• 400 g cooked Japanese short-grain rice, seasoned with sushi vinegar; kept at body temperature — not refrigerated
• 60 ml sushi vinegar (su), rice vinegar, salt and sugar combined at standard sushi proportions
• Assembly
• 4 sheets nori, peak freshness; use immediately — moisture degrades crispness within 5 minutes
• 20 g wasabi, freshly grated or prepared paste

Method

1. 1
   Scrape the tuna carcass using the suki-tori technique: drag a rigid spoon or the back of a yanagiba firmly along all bone surfaces — backbone, collar bones, and any skeletal surfaces — harvesting the fatty meat in thin ribbons. The yield is complete when no white or pink film of fat-streaked flesh remains visible on the bone.
2. 2
   Combine the scraped toro with the finely minced negi, soy sauce, sesame oil, and grated ginger. Work the mixture with a knife or spoon until the negi is evenly distributed throughout the tuna; no sporadic green clusters should remain. Taste: the negi sharpness should be present in every part of the mixture, the sesame oil perceptible but not dominant. This step decides the dish — too much sesame oil obscures the natural tuna fat; too little integration of the negi produces pungent, uneven bites.
3. 3
   Prepare the shari at body temperature. Season the cooked rice with sushi vinegar and fold — do not stir — until the grains are evenly coated and glossy. For the gunkan portions, the shari must be calibrated slightly firmer than standard: loose shari will collapse under the weight of the wet negitoro topping. The rice is ready when each grain holds its shape under light pressure but adheres to its neighbour.
4. 4
   For the gunkan maki: form 8 compact oblongs of shari, each approximately 18 g. Cut nori into strips of sufficient width to encircle each shari oblong with a 1 cm band projecting above the rice. Wrap the nori band as tightly as possible around each shari finger; press the seam closed with a grain of rice as adhesive. The nori should stand upright and firm — a loose wrap will unravel at the table.
5. 5
   Spoon the negitoro mixture into the nori cup of each gunkan until level with the top of the nori band. Apply a small amount of wasabi to the shari beneath the negitoro before topping. Serve within 5 minutes; the nori must still be audibly crisp when bitten.
6. 6
   For the tekka maki: lay a half-sheet of nori, rough side up, on a bamboo mat. Spread a thin, even layer of shari — approximately 100 g — leaving a 2 cm border at the far edge. Place one akami strip, cut against the grain, along the near third of the rice. Apply wasabi directly to the akami strip. Roll the mat forward in a single, firm motion to form a tight cylinder; the roll is complete when the far border of nori seals flush against the outside of the cylinder and the cross-section shows a centred core of fish with an even margin of rice.
7. 7
   Slice each tekka maki roll into 8 even rounds with a wet, sharp knife using a single drawing stroke per cut — sawing compresses the roll. Cut to order or within 3 minutes of rolling; nori softens rapidly from the moisture of the shari.