Bluefin Tuna Chutoro Saku Block

Chutoro — the medium-fatty belly cut of bluefin tuna, taken from the section between the lean loin (akami) and the richest belly (otoro). The name translates directly: chu means middle in Japanese, and that is exactly where this cut sits — in terms of both position on the fish and character on the plate. It carries more fat than akami, which gives it a softer texture, a slight sweetness, and a pink-to-deep-red colour that graduates across the block as the fat content shifts. But it stops short of otoro's full richness, which makes it arguably the most versatile of the three main bluefin cuts.

This is Mediterranean/East Atlantic bluefin (Thunnus thynnus), sourced through Fuentes, a Spanish producer with over 30 years of specialisation in bluefin tuna and the primary supplier to the Japanese market. Fuentes operates a full traceability system — every fish is individually identified, with microbiological analysis and fat content recorded and traceable back to the catch. The tuna is caught using purse-seine fishing under ICCAT-regulated quotas.

The block is supplied as a saku — a trimmed, rectangular portion cut to a uniform shape for clean, consistent slicing. This is the format used in professional Japanese kitchens for sashimi and sushi preparation, where uniformity of thickness matters for both presentation and texture on the palate.

The tuna is blast-frozen to −50°C immediately after butchery and stored at −60°C to preserve colour, freshness, and cellular integrity. Blast-freezing at these temperatures also eliminates parasitic risk, making the tuna safe to eat raw. Some colour change after defrosting is normal — the flesh may appear slightly darker due to natural oxidation, but this has no effect on quality or flavour.

Producer: Fuentes, Spain.

Ingredients: Bluefin tuna (Thunnus thynnus), chutoro cut.

Allergens: Fish