If you're wondering what sushi to eat, you may want to try this immensely popular bluefish is taken in shallow waters from the southern tip of Hokkaido to the East China Sea. Easily identifiable by its spiky dorsal scales, known as zeigo or zengo, it is affordable, tasty and chock full of vitamin B. There are around fifty varieties, most common being ma-aji, muro-aji and shima-aji.
Horse Mackerel on Ice at Kyoto's Nishikikoji Ichiba Market
Ma-aji is the most common and taken in waters off Nagasaki, Kagoshima, Wakayama and Mie. Muro-aji is found mostly in Nagasaki and Shimane Prefectures. Horse Mackerel caught in the Nomozaki district of Nagasaki and the Gonaji from the same prefecture's Gotonada are especially prized. Shima-aji grow up to 70cm in length, and are generally the priciest of the horse mackerel types.
We know that the Japanese have been eating aji for more than 1200 years, as it gets a mention in the Nara period collection of poetry, the Manyoshu, written some time after 759 AD.
It is the most versatile of fish. It may be served raw as sashimi, either finely chopped as aji no tataki or sliced as ito zukuri, literally 'thread sashimi', or vinagered as sunomono, or salted and grilled as aji no shioyaki, an izakaya favorite. In canteens and school refectories across the land it appears as aji no nitsuke simmered with sugar in shoyu, and sake, or fried in breadcrumbs as aji furai. The latter is a staple of cut-price teishoku lunch sets, bento boxed lunches and tachinomiya standing bars. Quality varies greatly, but when it's good it's fabulous!
When to eat
All year round, but best in the spring or early summer.
Where to eat
Any local shokudo canteen worth its salt will serve a decent aji furai teishoku set lunch. In terms of cost performance, it is unbeatable. Its more refined forms are found at good kappo style eateries and ryotei.
Aji no tataki paired with myoga Japanese ginger and shiso perilla leaf, and a fine, not too dry reishu cold sake.