Fresh, raw tuna reigns supreme in the culinary world these days, especially when it comes to sushi and sashimi. Bluefin tuna, known in Japan as hon-maguro or “true tuna,” is so popular that global stocks are dangerously low due to overfishing. But tuna didn’t always reign supreme: until the modern era it was considered a undesirable fish that was only fit for the lowest classes — and cats.
There were two main reasons for this disdain. An old Japanese name for tuna was shibi (the word is still used in some parts of Japan) and, though there are several theories about the origin of this name, it can be read as meaning “the day of death.” To the highly superstitious people of the Edo Period (1603-1868) — especially the samurai class — such pun-like coincidences were taken very seriously. So tuna acquired a reputation for being an unlucky fish. The other reason was that in the days before refrigeration, fish were kept alive for as long as possible to ensure their freshness, especially if they were prepared without heat. It was impossible to keep large tuna alive, so the flesh deteriorated rapidly. The fatty parts of the fish, which went bad before the lean parts, were so disliked that they were deemed fit only for cats. Those same fatty parts, called toro, are now the most in-demand and pricey parts of any fish; a slice of otoro (the fatty belly meat) is one of the priciest morsels you can put in your mouth.
When soy sauce became widely established as a cooking ingredient in old Tokyo during the mid- to late 18th century, people discovered that tuna kept longer and tasted better if it was marinated in a mixture of salty soy sauce and sweet mirin (a type of rice wine) or sugar — a method of marination called “zuke” — since both salt and sugar act as preservatives. Gradually tuna became more popular, but only the lean parts. With the advent of refrigeration, it became possible to freeze tuna as soon as it was caught to keep it fresh.
Because of the low-class reputation of tuna, until the 1890s most of it was consumed by the fishermen who caught it, and their families. Yet even they shunned the fatty parts. Toro has only been eaten in large quantities since the 1920s, when it was sold as cheap “emergency food” from street stalls after the 1923 Great Kanto Earthquake.
However, many regional recipes exist for lean tuna; the most popular is to cut up plain or marinated tuna and serve it on a bed of plain or vinegared sushi rice. This type of dish is often called tekka-don or “red hot iron rice bowl,” as the bright red color of lean tuna was likened to a red-hot iron poker. (Another theory for calling tuna “tekka” is that this type of quick dish was eaten at tekka-ba or gambling, aka dice-throwing, rooms in old Tokyo.)
This month’s recipe is not a tekka-don, but the principle is basically the same: lean tuna served with sushi rice. It’s a hearty and simple fisherman’s dish, and a specialty of the Ise-Shima region, Mie Prefecture, where the G-7 summit took place last month.
It’s important not to leave the tuna in the marinade for longer than 15-20 minutes, otherwise it becomes too salty. Because it is marinated, you can make this dish with the kind of tuna sashimi sold in supermarkets, as well as tuna varieties other than the endangered and expensive bluefin, and it will still taste good. On a hot summer’s day, I like to chill the tuna well and combine it with the rice at the very last minute.
Recipe: Tekonezushi (Marinated tuna sushi)
- 2 rice cooker cups (400 ml) uncooked Japanese-style white rice
- 3 tablespoons rice vinegar
- 1 teaspoon salt
- 1½ tablespoons sugar
- 2 tablespoons toasted white sesame seeds
- 300 grams akami (lean) sashimi-grade tuna
- 3 tablespoons dark soy sauce
- 1 tablespoon mirin
- 1 small piece (about 1.5 centimeters long) young ginger root, finely julienned
- 10 shiso (perilla) leaves, finely shredded
- ½ sheet nori seaweed, finely shredded
Rinse the rice several times. Drain and leave for 30 minutes. Place the drained rice in a rice cooker, add water and then remove 2 tablespoons of water. (If your cooker has a ‘sushi rice’ level, add water up to that level). Cook as usual.
Put the vinegar, salt and sugar in a small pan. Heat gently while stirring until the salt and sugar have dissolved.
Put the freshly cooked rice in a large bowl or a wooden mixing barrel (known as an oke or hangiri) and add the sushi vinegar. Mix rapidly using a cut-and-fold motion. Cover and set aside.
Cut the tuna into 6-mm-thick cubes. Combine the soy sauce and mirin, and marinate the tuna for 15 minutes in the refrigerator.
Remove the tuna from the marinade. Mix all the sesame seeds plus half of the tuna, ginger and shiso into the sushi rice. Transfer to serving plates and top with the remaining tuna, sesame seeds, ginger, shiso and nori.
If you don’t like raw ginger, use gari (sushi ginger) instead.