Japanese Spices and Seasonings: Wasabi, Sansho, Shichimi, Shiso, Karashi, Yuzu and More

Outside Japan, that green paste next to your sushi probably isn’t wasabi at all. Chowhound, citing the Washington Post, puts the share of fake wasabi sold in North America at about 99%.¹ Real wasabi is one of a handful of seasonings Japanese food leans on, with karashi for pungency, sansho and shichimi togarashi for heat and aroma, then shiso, sesame, negi, umeboshi and yuzu. Sansho, a close relative of Sichuan pepper, builds into a numbing, almost anesthetic feeling on the tongue.

At a glance

Wasabi

Wasabi is the rhizome (not the root) of Eutrema japonicum, a mustard-family plant (Brassicaceae) native from southern Korea and southern Sakhalin to Japan. Most of its heat comes from allyl isothiocyanate, the same compound behind horseradish’s flavor. One study found it made up 86 to 94% of the isothiocyanates in wasabi.² Those compounds form when the cells are broken, which is why wasabi gets grated just before serving, traditionally on a sharkskin or wooden grater.³ Japan’s embassy in Singapore says wasabi is paired mainly with sushi and sashimi.

Real wasabi is rare outside Japan. The wasabi paste in Western restaurants is commonly made from horseradish, and the embassy describes cheaper mixtures of horseradish, mustard and food coloring.⁴ Chowhound, citing the Washington Post, puts the share of fake wasabi sold in North America at about 99%.¹ Shizuoka Prefecture led Japan in water-grown wasabi rhizomes in 2022.⁵ See wasabi, fresh wasabi vs. wasabi paste, wasabi vs. horseradish and too much wasabi.

Karashi

Karashi is Japanese hot mustard. Just One Cookbook describes it as crushed Brassica juncea mustard seeds mixed with horseradish, spicier and more potent than mild yellow mustard.⁶ Kikkoman’s glossary calls it powdered Japanese mustard seed mixed into water or kneaded into a paste, hotter than Western mustard, and says it’s mainly sold in tubes in Japan.⁷ You can buy it as a powder or a ready-made paste. The two sources name oden, natto, gyoza and tonkatsu among its uses. You’ll occasionally see it labeled “pickled mustard” in English, but neither source describes karashi as pickled. See mustard powder, brown mustard seeds and horseradish.

Sansho

Sansho is the dried fruit of Zanthoxylum piperitum, a shrub or tree in the rue and citrus family. Its native range runs from China to southern Korea and Japan. It’s a close relative of Sichuan pepper, which comes from several related Zanthoxylum species. Katzer describes a fresh lime fragrance and a pungency that slowly builds into a numbing, almost anesthetic feeling on the tongue.⁸ The young leaves, kinome, are used fresh as a flavoring and garnish. Ground sansho is the classic optional topping for unagi don, grilled eel over rice.

Wakayama Prefecture is Japan’s main growing area, with 308 of the country’s 462 tonnes (66.7%) in the 2023 crop.⁹ See sansho pepper, sansho substitutes and Szechuan pepper.

Shichimi togarashi

Shichimi togarashi, “seven-flavor chile,” traces back to Karashiya Tokuemon at Yagenbori in Edo, in 1625. Chile, sansho and sesame are the standard core, and the rest varies by maker.¹⁰ Yagenbori and Kyoto’s Shichimiya Honpo both put sansho and sesame in their lists.¹¹¹² Just One Cookbook names ramen, udon, soba, gyudon, tonjiru and yakitori among its uses. See shichimi togarashi, nanami togarashi and shichimi substitutes.

Shiso

Shiso is Perilla frutescens, a member of the mint family (Lamiaceae). The leaves can be green or red to purple, and in Japan the red-leaved cultivars are preferred for pickling, for their color. Perillaldehyde is a major component of its essential oil.¹³ Katzer notes that the leaves garnish sashimi and can be battered and deep-fried, and that red perilla goes into umeboshi.¹⁴ You’ll see it claimed that Japan has used shiso for 300 years. We couldn’t trace that. See shiso and shiso substitutes.

Sesame, black and white

Toasted sesame is a common spice in East Asia, often sprinkled over Japanese and Korean dishes. Mix it with about 10% salt and you have gomashio, usually sprinkled over rice dishes.¹⁵ JustBento calls gomashio the most basic furikake. Black seeds get their color from a melanin-like pigment in the seed coat.¹⁶ Black sesame also turns up in desserts like ice cream. Sesame often gets called a superfood, but no regulator or systematic review backs that label. See black sesame seeds, black vs. white sesame, gomasio and furikake.

Furikake itself, literally “sprinkle,” is a rice seasoning. Just One Cookbook’s version combines bonito flakes, toasted sesame, nori, sugar and salt.¹⁷ See gomasio vs. furikake.

Negi

Negi is the Welsh or Japanese bunching onion, Allium fistulosum. It’s known only in cultivation and probably comes from northwestern China. PROSEA says that in Japan it’s second in importance only to the common onion. East Asian forms are grown for their thick, blanched pseudostems, eaten as a pot herb, while in Southeast Asia the plant is grown mainly for its green leaves. Its aroma isn’t very strong and comes from volatile allyl sulphides.¹⁸ You’ll often read that the white parts get cooked and the green parts go on as garnish, and that preferences differ by region within Japan. We couldn’t trace either claim. See chives vs. green onions and garlic chives.

Umeboshi

Umeboshi are the salted, pickled fruit of the ume tree (Prunus mume). They’re called plums in English, but the fruit is closer to the apricot. Nippon.com describes them as sweet, sour and salty, eaten with rice or used to accent other dishes, and mentions a version made with purple shiso for color and flavor. Wakayama Prefecture makes 60% of Japan’s production.¹⁹ The liquid left over from making umeboshi is used to color pickled ginger.¹⁴ Umeboshi is the whole fruit. The paste (bainiku) is a separate product our sources don’t cover.

Yuzu

Yuzu (Citrus × junos) is an accepted species in the rue family. Britannica says it may have started as a hybrid of the sour mandarin and the Ichang papeda, probably in China, but it’s now most associated with Japan.²⁰ The fruit has bumpy golden-yellow skin, seldom grows much bigger than a tennis ball, and is too bitter to eat on its own. The fragrant peel goes into soups, salads and simmered dishes at the last minute, and the juice is one option for the dipping sauce ponzu.

Related pages

• Japanese curry powder
• Korean spices
• Wasabi powder vs. paste
• The master list of herbs and spices