What is Zuniku?
Zuniku (頭肉, "head meat") is taken from the frontal section of the Bluefin’s head, above and behind the eyes. The yield per fish is extremely small, which is why Zuniku is rarely found even at premium Japanese fish markets.
The texture is unlike any other cut: incredibly soft, with a high fat content that is uniformly distributed — less marbled than Otoro, more consistently silky from edge to edge. Customers reaching for comparisons often land on high-grade wagyu.
Availability: One of the most limited cuts on the fish. Available at market price when the weekly Bluefin allows — check the shop or ask in-store.
How to eat it
Raw, sliced 8–10mm, with tamari. The texture is the experience — nothing more needed. A gentle sear (tataki) — 10 seconds per side over very high heat — is also exceptional: the exterior caramelizes while the interior remains raw. Do not overcook; Zuniku has no tolerance for more than a few seconds of heat.
Where this fish comes from
Every piece of Bluefin Tuna at Sashimi DC comes from Hosei Suisan (宝生水産), a farm in the Kamishima Wakamatsu area of the Goto Islands, Nagasaki Prefecture — the westernmost islands of Kyushu, where the Pacific and East China Sea converge.
The Goto Islands maintain water temperatures that never fall below 13°C in winter and rarely exceed 29°C in summer — the stable, narrow range that Bluefin Tuna require for consistent growth and quality. Hosei Suisan operates in the Kamishima Wakamatsu area, one of the most environmentally favored zones for marine aquaculture within the islands.
Hosei Suisan uses wild-caught seed stock (天然種苗) rather than hatchery-bred fish. Feed is sourced fresh and locally, centered on fresh mackerel (生サバ) bought directly by their own trucks from local fishermen. Director Tsuneya Yamashita explains the choice: mackerel produces better fat marbling and color than sardines. As mackerel catches have declined and prices risen in recent years, they secured dedicated year-round supply agreements with their fishing partners to maintain the standard. Post-harvest handling — the initial processing and preparation after the fish is landed — is also a focus: Ikejime is performed in Nagasaki, at source.
Two-time award winner: At the Nagasaki Prefecture Farmed Bluefin Tuna competition on December 8, 2023 — showcasing the fish from Japan’s leading farmed Bluefin production prefecture — Hosei Suisan was awarded the top prize (最優秀) for the second time.
After Ikejime processing in Nagasaki, the fish is transported to a specialist Miyazaki processor where it is broken down into saku blocks, then flown Fukuoka → Haneda → IAD.