A box of Hokkaido sea urchin from NYC hotspot Sushi Zo

Japanese cuisine has continued to see a steady increase in popularity in the United States over the past few years.

Long gone are the days in which people were familiar only with shrimp tempura and spicy-tuna rolls. More and more of the cuisine’s intricate ingredients are making their way Stateside, and diners’ palates are constantly evolving. Here, we answer a few questions about Japanese delicacies with which American diners may not profess familiarity. One thing is for sure: We’re not in California-roll land anymore.

1. What is firefly squid?
You may be familiar with many Japanese culinary ingredients, but what about this tiny squid that has the ability to light up in striking fluorescent blue when it feels threatened? Its unique, strong taste elicits a “love it or hate it” response from diners.

There are several differences between freshwater and saltwater eel. (Photos: Jeremy Keith; T.Tseng/Flickr.)

2. What are the differences between freshwater and saltwater eel?
You’ve undoubtedly eaten eel at a Japanese restaurant. But did you know that there are two different types commonly served? And that they are quite different, in terms of both taste and texture?

(Photo: Mon OEil/Flickr.)
The refreshing shiso leaf is used in a number of Japanese dishes. (Photo: Mon OEil/Flickr.)

3. What is shiso and how is it used?
To answer the question straightforwardly, it’s Japanese mint. The refreshing herb is used extensively in several kinds of Japanese cuisine. Here are a few places you may have seen it while dining out.

(Photo: Joe Bielawa/Flickr.)
Tobiko can be infused with different flavors, resulting in color changes. (Photo: Joe Bielawa/Flickr.)

4. What are the different types of fish eggs in Japanese cuisine?
Masago. Tobiko. Ikura. What are these three types of eggs, and what are the differences in their size, color and taste? And how is each best used in Japanese dishes?

You love chicken teriyaki. But what is really in that magical sauce?

5. What exactly is teriyaki sauce made of?
“I’ll have the chicken teriyaki, please.” It rolls off your tongue like second nature at your neighborhood Japanese joint. And you know exactly what the sauce will taste like. But what is it, exactly?