Sushi toppings are further topped with just a top of certain condiments. Can you identify them? Why are they used? Even Japanese people can’t answer these questions, but you can learn the answers here.
Nitsume (marinating), Nikiri (boiling down), citrus juices and salt. These remain the main four seasonings used at sushi restaurants. Sudachi was the first citrus juice used in preparations, then the use of yuzu and lemon became common, and there are some chefs that also use yuzu salt, spicy mustard and grated garlic. Setting aside the debate that some of these condiments deviate from the essence of Edomae sushi, there is no doubt that condiments bring out the flavors of sushi toppings.
Let’s take a look at the characteristics of spices and condiments often used in Japanese cuisine.
Shoga (Ginger)
Shoga is a perennial plant that was already being used as a preservative and medicine in India as early as 300-500 BC. It is a aromatic vegetable said to have been introduced from China before the 3rd century AD. The main edible part is the enlarged underground stem. While it does not contain any particularly notable nutrients, it is characterized by its strong aroma, spiciness, and medicinal properties.
The distinctive spiciness is due to its components, gingerol and shogaol. Shogaol is not present in fresh ginger; it is generated during preservation processes like drying and storage, or during cooking processes like heating. The chemical structure of gingerol is similar to capsaicin found in chili peppers and piperine found in black pepper. Heating transforms it into zingerone, which gives shoga its characteristic pungent, sweet aroma. When dried, it loses a hydroxyl group and further transforms into shogaol, which has an even stronger pungent effect. Dried ginger is spicier than fresh ginger because shogaol is produced.
Zingerone, a distinctive aromatic component of ginger, contributes to its fragrance but has no spiciness. It is not present in fresh ginger but is formed from gingerol via the reverse aldol reaction during drying and storage. Gingerol promotes blood circulation and sweating, helping to warm the body and boost metabolism. Gingerol also has high antioxidant properties and is said to have anti-cancer effects.
Galanolactone, a refreshing aromatic component unique to ginger, is found only in Japanese ginger.
Additionally, its distinctive appetizing aroma makes it widely used as a spice. The compounds responsible for this aroma include zingiberene and citronellal. These compounds also have deodorizing and detoxifying properties.
Asatsuki
“Asa” means shallow and “tsuki” means green onion, and this particular plant is named because of its color, which isn’t as dark as green onions. It is a separate species from onions and is characterized by its more pungent spicy flavor.
Shiro-negi (Japanese leeks)
These are also known as “Naga-negi (long onions)” or Japanese leeks. These onions are common in East Japan, characterized by the thickness and large white space. Usually, the white portion is eaten. It softens and has a sweetness when it is heated. It also has spicy, onion components and the white portion has high allyl sulfide content, which is known for aiding in digestion, so it has more medicinal effects than leafy onions.
Chopping Negi (Shiro-negi or Ao-negi) activates the hydrolytic enzymes within them upon contact with oxygen. These enzymes act on alliin, a sulfur-containing compound within the molecules, converting it into pungent allicin and other sulfides. These sulfides produce the distinctive pungent spiciness and aroma of negi. Diallyl sulfide is the primary component.
Ao-negi (Green onions)
Ao-negi is also called leafy onions and refers to onions with more green space. It mainly grows in Western Japan, is thinner than shiro-negi and is characterized by how it branches near the root. The leaves are soft, it has a unique onion scent and is great for condiments, stir-fry and miso soup.
Bannou-negi
This is a brand name for small green onions. Small green onions are young ao-negi. They are generally 5 mm in diameter and 50 cm long and used for condiments. Fugu-negi (Yasuoka onions) is another type of small green onions.
Kujo-negi
Kujo-negi are green onions indigenous to Kyoto and have been growing mostly in the Kujo Village (currently Sakyo-ku of Kyoto city) since the Nara era. It is soft and has a pleasant taste and is perfect for dressed fish/vegetables (aemono), condiments and hot pot dishes. There are 2 types: Light-yellow (hoso-negi) and black (futo-negi). The texture is soft and there is a sweet element, and the inside of the leaves is slimy.
Me-negi
These are green onions harvested immediately after sprouting. They are 6-10 cm in length and look like pine needles. They have a refreshing taste that isn’t as spicy, so it is used as a condiment or a sushi topping.
Wakegi (Tufted stone leek)
This is a mixed breed of green onion and white onion mainly found in Kansai and further west. It’s not as pungent and the fragrance is more subtle without the unique onion spiciness and there is an element of sweetness.
Myoga
Myoga is a perennial herb of the ginger family native to East Asia. What is commonly called “hana-myoga” or ‘myogako’ is the flower spike, which contains 3 to 13 unopened flower buds inside. These are called “flower buds.” Myoga is not the leafy part growing above ground; instead, the buds are picked directly from the rhizomes growing underground.
On the other hand, the young shoots that are blanched and lightly colored pink by weak light are called “myoga-dake.” Its unique aroma is highly valued, and it is used as a fragrant vegetable, a garnish for soba noodles, somen noodles, and chilled tofu. It is also used as an ingredient in tempura, vinegared dishes, clear soups, and miso soup. Its distinctive fragrance enhances the enjoyment of meals.
The main aromatic component is α-pinene, a type of organic compound called a monoterpene. Its name originates from pine, as it resembles the main component of pine essential oil. Pinene has an internal double bond; depending on its position, it can be α-pinene or β-pinene. The aroma of myoga comes from the α-type.
Myoga with small buds is available in summer, while thicker, firmer varieties appear in autumn. Summer myoga is best used as a condiment to highlight its aroma and flavor. Autumn myoga is larger and more fragrant, making it ideal for use whole in tempura or vinegared dishes.
The α-pinene in myoga’s aroma is known to calm nervous excitement and alleviate stress. It is recognized as effective for clearing the head or dispelling drowsiness.
The red pigment is malvidin, a type of water-soluble anthocyanin plant pigment. While myoga is sometimes sliced and soaked in water to remove bitterness, malvidin is water-soluble and leaches out through the cut surfaces. To maximize intake of the active components, keep soaking time as brief as possible.
Ooba
This is the perilla leaf (shiso), but generally, it is only called green shiso when used in full leaf form as a potherb. You’ll find Shiso all year long, but its true season is summer. It has a high nutritional value and as a vegetable, it has an extremely high content of β-carotene, B vitamins, vitamins C, E and K, iron, calcium, potassium, zinc, etc. Lately, it has also become a point of focus due to its high antioxidant effects. Also, the fragrant components and sisoaldehyde stimulate the olfactory cells, promoting secretion of saliva and gastric juices, improving appetite and promoting digestion absorption. Perilaldehyde also has bactericidal and antiseptic effects. It is a monoterpene containing an aldehyde group.
What is the difference between Shiso and Ooba?
Yuzu
It is about 100-120 g in size and has a rugged, yellow rind. Yuzu is a Kosan citrus (fragrant/acidic citrus) fruit* with a unique fragrance and acidity and plays a role in bringing out the flavor of a variety of foods.
*Citrus fruits not good for eating raw, with stronger acidity than the typical tangerine type of citrus, are called “Kosan citrus”. The most common are lemon and lime. They have a nice fragrance so they are squeezed and added as seasonings or used for juice.
Yuzu is a specialty product of Kochi Prefecture. The yellow yuzu that appears around November to December is well known, but green yuzu (called ao yuzu) is also available from August to October.
While it has a higher sugar content than kabosu or sudachi, when green, it has a strong sourness and bitterness, resulting in a complex flavor. The peel of yuzu contains a unique aromatic compound called “yuzunon,” making it ideal for flavoring dishes and masking the fishy smell of fish. By grating or slicing the peel, or squeezing the juice with the peel facing down, you can utilize its vibrant aroma.
The slippery part on the surface of the seeds is “pectin,” which has high moisture-retaining properties and helps bind collagen. It is reportedly used in cosmetics.
Sudachi
Sudachi, from the same kosan citrus family as yuzu, weigh 30-40 g. They are a famous specialty of the Tokushima prefecture. They are characterized by brisk acidity and refreshing aroma. It is not generally eaten whole, but serves to flavor other foods. It is common to add a small amount of sudachi to sashimi, grilled fish, and noodle dishes. It is a standard ingredient in the production of ponzu (a citrus-based sauce widely used in Japanese cooking).
Sudachi fruit juice contains high levels of citric acid and has a strong peel aroma, making it a valuable condiment despite its small size. They contain flavonoids called Sudachitin and Demethoxysudachitin. The juice’s aroma components include Nonanal, Decanal, as well as Aldehyde C11 and Aldehyde C-12. The peel’s fragrance is contributed by Linalool, Yuzunone, and Wine Lactone.
<Purpose of Using Sudachi in Nigiri Sushi>
・To Add a Fragrant Accent
Sudachi is known for its sharp, refreshing aroma. Just a few drops can dramatically enhance a piece of nigiri, especially with delicate toppings like white fish, shellfish, or gizzard shad (kohada). The citrus fragrance adds depth and elegance to the overall experience.
・To Provide a Bright, Clean Acidity
Compared to kabosu, sudachi has a more pronounced, crisp acidity. It helps define the flavor of lighter fish, tightening the umami and bringing clarity to each bite—almost like drawing a clean outline around the taste.
・Ideal for salt-seasoned Nigiri sushi
Sudachi pairs exceptionally well with salt-only preparations. When a slice of fish is topped with just a pinch of salt and a drop of sudachi juice, it reveals the ingredient’s natural flavor in a simple yet refined way.
・To Express Seasonality
Sudachi is in season during the autumn months, making it a perfect match for seasonal ingredients such as grilled sanma (Pacific saury) or matsutake mushrooms. Its use helps convey a sense of season in the sushi course.
・For Visual and Sensory Impact
Thin slices of sudachi placed on top of the sushi not only add a pop of color but also gently release their aroma as the sushi is lifted to the nose. In many high-end sushi restaurants, this subtle aromatic detail is used as part of the overall presentation.
Kabosu
Like sudachi, kabosu are also from the same family as yuzu and are similar in looks, but they are much larger, weighing 100 to 150 g and have even stronger acidity. They aren’t just sour, they also have a gentle sweetness. A specialty of Oita prefecture, they are often used to add flavor to fugu (blowfish) dishes, hot pot and grilled fish. Sashimi also pairs well with kabosu, and the fruit is either squeezed directly over the seafood or added to soy sauce and used for dipping.
The main component of kabosu’s sourness is citric acid, which it contains twice as much of compared to lemons. Its sourness is milder than that of vinegar. The minerals in kabosu appear to influence its salty, bitter, and sweet flavors. The primary aromatic compound in the peel is limonene, along with myrcene, terpinene, and pinene. Other compounds contributing to the aroma include linalool, decanal, octanal, citronellol, and geraniol.
<Purpose of Using Kabosu in Nigiri Sushi>
・To Refresh the Palate When Paired with Rich Fish
Kabosu has a mild acidity and abundant juice, making it ideal for balancing the richness of fatty fish such as toro (fatty tuna), mackerel, or nodoguro (blackthroat seaperch). Its gentle sourness cuts through the oiliness and leaves a clean, refreshing finish.
・Perfect for salt-seasoned Nigiri sushi
Instead of soy sauce, kabosu is often paired with a touch of salt to season nigiri. This style, known as shio nigiri, highlights the natural flavors of the fish. A few drops of kabosu juice enhance the umami while adding a light citrus brightness.
・To Subtly Enhance Aroma Without Overpowering the Fish
Compared to sudachi, kabosu has a softer, more rounded aroma. This makes it well-suited for delicate white fish, where it complements rather than overwhelms the natural scent of the seafood.
・To Express Seasonality and a Japanese Sensibility
Kabosu is in season from late summer to early autumn. Its fresh and gentle fragrance adds not only flavor but also a subtle seasonal and traditional touch to the sushi experience.
Hebesu
This kosan citrus from Hyuga, Miyazaki is similar to the kabosu and sudachi. It is about the size of a kabosu and sudachi. The season is from August to October.
Its key features include thin skin and few seeds, allowing for a high juice yield per fruit. Its gentle flavor and subtle sweet aroma make it ideal for use in ponzu sauce and dressings.
It also contains eight of the nine essential amino acids and is rich in natsudaidain, a flavonoid component said to have cancer-preventive effects, making it an excellent nutritional ingredient.
Daidai
The mature Daidai fruit doesn’t fall from the tree as easily as other edible fruits, so it is used as a decoration for the New Year as a symbol of good fortune. While the juice has a hint of sweetness, it has a strong acidity and also a bitter element.
Daikon-oroshi (Grated daikon)
This is grated daikon radish. When using daikon radish as a condiment, the tip is used if a more pungent flavor is desired and the area closer to the base of the leaves is used for less spiciness.
Momizi-oroshi (Grated daikon and chili)
Make several holes in a peeled giant white radish with chopsticks, stuff them with red pepers, stem and seeds removed, after reconstituting them with lukewarm water, and grind the radish together with the peppers.
Bainiku (Plum pulp)
This is the part of pickled plums with the seed removed.
Mominori
This is finely ground, lightly toasted laver.
Next, we would like to introduce the typical sushi dishes that use these types of condiments. Here we explore the uses and potential uses of the major condiments.
Mackerel・Pacific saury・Sardines
Just by serving with grated ginger or grated ginger and green onions (or Asatuki), the peculiar taste of mackerel fat completely transforms into something elegant. Grated ginger is effective in accentuating the unique umami flavor of sushi toppings and is also used with Pacific saury, sardines and horse mackerel. Most sushi restaurants use it in a standard way.
Bonito
In order to cancel out the raw odor of bonito, sushi chefs smoke the fish with straw and typically treat it with green onion and grated ginger.
Squid
How to prepare squid is something that each sushi chef has to decide. Some use salt and sudachi for a refreshing sweetness. Others sneak Oba between the topping and shari to bring out the natural umami of the squid.
Blowfish
Fugu (Blowfish) known for its light and delicate taste, so it’s not suitable to use condiments that are too strong. Fugu-negi is ultra-thin and soft with a nice fragrance without being overbearing and it’s the best onion for the delicate blowfish. And instead of nikiri (boiling down), it goes well with mellow, acidic Ponzu*, which brings out the flavor of fugu.
*Traditionally ponzu refers to a vinegar sauce made from citrus fruits like kabosu, but “ponzu soy sauce” (traditional ponzu sauce combined with soy sauce and mixed with bonito stock and kelp stock) is also generally known as “ponzu”.
Pen shell
Sushi chefs struggle to bring out the sweetness of the pen shell, which is stronger than that of scallops. Adding the oba leaf between the topping and the rice does wonder in bringing out the sweetness and umami.
Horse mackerel
This was the brainchild of the legendary sushi chef, Shuzo Okada, in order to emphasize the umami of fish with peculiar tastes such as horse mackerel. Just a dash of deep green seasoning made from grinding down Asatsuki and ginger is placed on top of the sushi topping.
In addition to making the sushi look beautiful, it also gives toppings with delicate tastes a more distinct flavor, subdues the persistency of fat. As I mentioned before, too much flavoring deviates from traditional Edomae sushi, turning the dish into “Sousaku-zushi” or “creative sushi”. Of course whether or not to use condiments is up to how the sushi chef feels. And a sushi chef may not use the same condiments every time. Considering each of the individual condiments used, you can’t help but feel the depth of Edo-style sushi.
Related contents:
The role of green onions in sushi
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