The Japanese love to eat – and the people in this country love fish in general (though not everyone likes it. In fact, to break any stereotypical image you might have, there’s actually quite a sizeable number of Japanese people who simply hate fish). When you go to a sushi restaurant, you might be overwhelmed by all the different names of the fishes you see on the menu. What’s worse, most of them do not have an English equivalent name. In this article, you will learn about出生魚 “shusseiuo”, a particular category of fish that’s particularly common as sushi toppings. Knowing about “shusseiuo” will help you to make better judgement on what to eat the next time you have a craving for sushi.

Considering the worldwide fame of sushi, you probably already know what it is. But just in case, here’s a quick primer:
Sushi is basically a small roll of rice with a topping. The topping is generally raw seafood – raw fish, raw shrimp, raw scallop, raw squid, raw octopus, raw, raw, raw… It might also be cooked seafood, or even egg as well. Some parts in Japan serve raw horsemeat sushi. To cater to a variety of customers, some sushi restaurants serve cooked pork meat sushi, hamburger sushi and the like. Not very traditional, but yes, they do exist. Again, just for the record, there are more Japanese people who don’t like sushi or raw food than you might think…

Back to “shusseiuo”. “Shusseiuo” refers to a category of fish whose names change as they get larger (i.e. grow older). Up until the Edo period (1603), samurai had a custom of having their names changed according to their (rising) statuses - the habit of naming certain fish “shusseiuo” is derived from this. Some of the more common “shuseiuo” are “buri” (yellowtail), “suzuki” (Japanese sea bass) and the enormous “maguro” (tuna). Depending on the area, “shusseiuo” names in the same length category may vary. “Shusseiuo” are considered auspicious fish, and are therefore served during festive seasons like New Year’s Day and Children’s Day in Japan.

To give you a better idea of how the “shusseiuo” system is like, here are the statistics of buri (yellowtail) and its different names according to its length and location.

buri (yellowtail)
Full-blown Adult Length: 100cm~

East Japan:
wakashi (~20m) -> inada (~40cm) -> warasa (~60cm) -> buri (90cm~)

West Japan:
tsubasu (~15cm) -> hamachi (~40cm) -> mejiro (~60cm) -> buri (90cm~)
　

Why is the same fish called one thing in east Japan, and another in west Japan? Here’s a fact that could point to the answer: There was a very long period in Japan’s history when it was a country embroiled in internal turmoil, savaged by wars, before it was finally unified one fine (bloody) day…

And why is there a need to name the same fish differently according to their sizes? The better to eat them with, my dear…

Generally, “shusseiuo” are considered the most delicious when they reach their full-blown adult stage. Not surprisingly, they’re also the oiliest, and the most expensive at this stage. Interestingly however, there’s apparently not much change in the taste itself… They do look somewhat different though.　Perhaps it’s just a psychological thing? Make your own judgement next time you go to a sushi restaurant.