Seafood ── Fish
Aji
horse mackerel — the fish behind Japan's everyday fry and sashimi
A blue-backed fish sold year-round, served raw, minced as tataki, or fried. Fish that settle in one fast-flowing strait rather than migrate firm up and fatten, and are pole-and-line caught there under premium regional brand names.
- Blue-backed fish
Lineage
What it's made of
A blue-backed fish sold year-round, but fish that settle in one spot rather than migrate run fattier and sweeter raw, mince well into tataki with herbs, and fry up with a fat-rich sweetness concentrated inside the crust. It peaks from early to midsummer, when the fat under the skin runs thickest and sashimi turns especially smooth.
How it's made
Fish that hold their ground against a fast current rather than migrate build muscle and hold onto fat. Taken one at a time by pole-and-line rather than net, they're bled alive on deck, which slows deterioration and keeps them fit to eat raw. Because it carries many small bones, sashimi sometimes gets fine scoring similar to hone-kiri, and tataki is minced skin-on so the fat blends with the aromatics.
Why it took this shape
Horse mackerel that settle in the Bungo Channel's fast currents rather than migrate are said to firm up and fatten, and in Oita City's Saganoseki, pole-and-line-caught fish are sold as 'Sekiaji'. Wherever tidal flow is strong enough to favor these resident fish, similar branded catches have emerged along the coast — and within the same species, migratory and resident fish end up tasting, and being treated, quite differently.
Before You Go
- How to shop at a supermarketHow to choose prepared foods, sashimi, and packaged sushi, when discount stickers tend to appear, region-only specialties, buying by weight, the checkout and bagging flow, and sampling etiquette at a local supermarket.
- Roadside stations, direct-sale stands, and marketsHow to enjoy buying food near where it's produced, visiting and shopping at morning markets and fish markets, what to expect at farm stands, and finding local food at roadside stations (michi-no-eki).
- Foods to look for in springA guide to foods often seen in Japan around spring — early bonito, bamboo shoots, sakura mochi, hanami bento, new-season tea, and butterbur sprouts — with rough pointers for finding them.
Dishes in the same style
- BuriA 'shusseuo' whose name changes with size. Winter's fat-laden 'kanburi' is prized raw, teriyaki-glazed, or simmered with daikon — bays where it fattens before wintering, then is taken in set nets, are valued for both fat quality and yield.
- IwashiA small, schooling blue-backed fish eaten raw, simmered with plum, or as tsumire dumplings. Its fat quality tracks the tidal boundary it feeds along, and ports facing where cold and warm currents meet land the most — dried, it becomes niboshi dashi stock.
Ingredients and dishes from this land
Known for it here / Known source
- Known for it here: Oita, Saiki
Fish held in place rather than migrating through the fast currents of the Bungo Channel firm up and fatten into the branded 'Sekiaji'.
- Known source: Shizuoka, Numazu
Uses
- Iwakuni-zushiA pressed sushi from Iwakuni, layered three to five tiers deep in a wooden frame. Lotus root, shiitake, and shredded egg stack into a striped cross-section — a dish also known as 'the lord's sushi,' cut and shared at celebrations.
- Jako-tenWhole small-fish paste, bones included, fried into an oval cake, an Ehime specialty. Said to trace to Uwajima's first domain lord bringing a kamaboko craftsman from Sendai, its name reflecting a habit of using odd, mixed catch fish without waste.
- Aji FryFilleted horse mackerel breaded in panko and fried. Chiba prefecture holds some of the richest mackerel fishing grounds in Japan, and frying is thought to have taken root as a quick way to eat regional brands like the oily 'golden aji' fresh.
- Aji no SanbaiAji (horse mackerel) is grilled until lightly charred, then steeped in a three-part vinegar dressing sharpened with chili and ginger. The vinegar is said to soften the bones enough to eat whole, and the dish has long served as a summer festival accompaniment to drinks around the Seto Inland Sea.