Kohada, the Edomae Touchstone: Salt, Vinegar and July’s Shinko

Few fish reveal a chef’s hand as honestly as kohada, the gizzard shad. It has never been an expensive fish, yet Edomae sushi houses, keepers of the old Tokyo style, have long measured a craftsman’s skill by it. Here we look at why kohada is known as a touchstone, what the work of salt and vinegar actually involves, plus shinko, the infant fish whose season opens each July.

A sushi house reveals itself in its kohada

So the old saying goes. The reason is simple: kohada is not a fish whose quality can be bought at the market. Where tuna can carry a piece on the strength of the ingredient alone, kohada depends entirely on the hands that prepare it. How the salt is applied, how long the fish rests in vinegar, how the knife scores the skin: these decide everything. There is nowhere to hide, which is why a chef keeps returning to this one fish for a lifetime.

Among the silver-skinned fish known as hikarimono, kohada allows the widest range in how firmly it is cured. Two houses working with the same catch on the same day will serve two entirely different pieces. Few toppings reward comparison quite so richly.

From shinko to konoshiro: a fish that changes its name

Kohada is what the Japanese call a shusseuo, a fish renamed as it grows. The fry born in summer are shinko; a little larger they become kohada; larger still, nakazumi; the fully grown fish is konoshiro. Curiously, its market value falls as it grows. What sushi chefs prize is the small, labour-intensive shinko together with kohada.

Salt and vinegar: judgement, not recipe

The preparation begins with butterflying each fish, then salting it. Salt draws out excess moisture along with any lingering odour, firming the flesh. Then comes the vinegar. The difficulty is that neither step can be fixed in minutes: the right timing shifts every day with the size of the fish, how much fat it carries, even the temperature of the room.

1. Butterflied, then saltedSize and fat content decide both the amount of salt and the time it stays on.
2. Rinsed cleanThe excess salt is washed away while the chef checks the state of the flesh.
3. Rested in vinegarThe heart of the cure. Too brief and the fish tastes raw; too long and it turns firm.
4. Left to settleLifted from the vinegar, the fish rests a while so the flavour can compose itself.

July, when the shinko season begins

In July, shinko reach the counter. These are tiny fish, a few centimetres long, so small that two or three fillets are draped over a single bed of rice in what chefs call a layered piece. The smaller the fish, the harder it is to open, harder still to cure; the labour dwarfs that of ordinary kohada. Yet many guests wait all year for the first shinko, because its pale, delicate flavour exists only in these few weeks.

At Sushi Tanji in Oku-Akasaka, the air in the kitchen changes when the shinko arrive each July. For a house devoted to the classical Edomae repertoire of curing and marinating, shinko marks a turning point in the year.

Enjoying kohada at the counter

In an omakase course, where the chef sets the progression, kohada tends to appear around the middle. Because the fish is already cured, it wants very little soy sauce; where the chef brushes it with nikiri, a seasoned soy glaze, the piece is complete as it arrives. Hands or chopsticks, whichever feels natural, will serve you well. The decorative knife work scored into the silver skin is not merely ornamental; it softens the cured flesh into an even, pleasing bite.

The tang of vinegar, the company of sake

Cured in vinegar as it is, kohada may be the topping most often discussed alongside sake. Many guests reach for a kimoto, a traditionally fermented style with firm acidity; others prefer a clean, unadorned junmai. The pleasure of changing your drink from piece to piece is perhaps most vivid with kohada. When in doubt, simply ask across the counter; the question is always welcome.

Frequently asked questions

Reviewed by

Tatsuo Takada

Head chef and owner of Sushi Tanji. Trained in the Edomae tradition and rooted in Kyushu, he leads the eight-seat omakase counter in Oku-Akasaka, Tokyo, and reviews The Tokyo Sushi Guide.