Dashi: The Quiet Broth Behind Japanese Food and the Name Umami

Updated October 15, 2026 | By Tokyo Paul

A bowl of clear soup arrives with a few cubes of tofu, a scatter of green onion, and almost nothing else to look at. One sip, and the flavor stretches on far longer than the ingredients suggest: round, savory, faintly of the sea, and somehow satisfying without a drop of oil or cream. The explanation is not in the tofu. It is in the liquid, a pale gold stock called dashi that sits underneath most of Japanese cooking and rarely draws attention to itself.

Dashi is traditionally made from kombu (dried kelp) and katsuobushi (dried, fermented skipjack tuna). It is the base for miso soup, noodle broths, steamed egg custard, and simmered vegetables, and it even goes into the batter for okonomiyaki and takoyaki. It is also the reason a scientist at the University of Tokyo, Kikunae Ikeda, gave the world the word umami. Here is how the broth is made, how it was understood, and how to recognize it on your own table.

Kombu: The Kelp at the Base

Kombu is a thick, dark, leathery kelp that is dried in sheets and sold folded or cut into strips. It is rich in glutamic acid, the amino acid behind much of its savory depth. Much of Japan's kombu comes from the cold waters off Hokkaido, and different varieties suit different uses. Rishiri kombu is commonly used for soup stocks, while other varieties differ in sweetness and body.

The technique is gentle. Kombu is soaked in water for a long time, or warmed slowly and lifted out before the water boils, because kombu that is boiled turns bitter. Kombu has a regional footnote as well: Okinawa households use more kombu than any other prefecture, a habit that dates to the Edo period (1603 to 1868), so the kelp is part of local home cooking there and not only a stock ingredient.

Katsuobushi: Tuna as Hard as Wood

Katsuobushi starts as skipjack tuna that is filleted, simmered just below boiling for an hour or more, then smoked in repeated cycles over several weeks. The finest versions are sprayed with a beneficial mold and sun-dried several times, a process that drives out moisture and deepens flavor. The result weighs less than a fifth of the original fish and is so hard that it can sound almost metallic when tapped.

Traditionally it was shaved at home on a wooden box fitted with a blade, rather like a carpenter's plane. The paper-thin flakes (kezuribushi) are what you see waving on hot okonomiyaki or takoyaki; the heat rising from the food makes them ripple. Katsuobushi is also scattered over cold tofu and rice, and it turns up as a filling in onigiri (rice balls). The flavor comes from inosinate, a compound that plays a key role in umami science.

Ikeda Names the Fifth Taste

Kikunae Ikeda studied in Leipzig, Germany, from 1899 to 1901. He had grown up loving dashi, and he noticed that some European dishes, such as tomato-based stews, shared a certain savory quality with Japanese food. Back in Tokyo, he became curious about what made kombu broth so satisfying. The usual four basic tastes, sweet, sour, salty, and bitter, did not account for it. His investigations led him to isolate glutamate from kelp and publish his findings around 1908. He named the new taste umami, from the Japanese word for deliciousness.

A year later, in 1909, Ikeda and businessman Saburosuke Suzuki began producing a seasoning based on monosodium glutamate under the brand name Ajinomoto, which means essence of taste. The company still exists today. Ikeda's student Shintaro Kodama showed in 1913 that katsuobushi contains inosinate, a second umami substance, and in 1957 Akira Kuninaka identified guanylate in shiitake mushrooms as a third. The term umami was formally adopted at an international symposium in Hawaii in 1985, and researchers found taste receptors for it on the tongue in 2000.

Types of Dashi

Kuninaka also showed that glutamate and these ribonucleotides amplify each other, which is why classic dashi pairs kombu with katsuobushi: together they taste far stronger than either alone. Ichiban dashi (first dashi) is the delicate, clear version made with kombu and katsuobushi, used in suimono (clear soups) where the broth itself is the star. Niban dashi (second dashi) reuses the leftover ingredients for a lighter, everyday stock suited to simmered dishes. Niboshi dashi uses small dried sardines and has a stronger, rustic character, common in home-style miso soup. Shiitake dashi, made by soaking dried mushrooms, is the backbone of shojin ryori, the vegetarian cooking of Buddhist temples.

Visitors who avoid fish should know that dashi is often hidden. Miso soup, udon and soba broth, oden, and many seemingly vegetable dishes may be made with bonito stock. Menus rarely list it. If you follow a vegetarian diet, ask whether a dish contains dashi, or look for temple cuisine and restaurants that advertise vegetable stock. Staff are often happy to explain, particularly when you ask politely and early.

Dashi in Everyday Cooking

Dashi is the quiet workhorse of the Japanese kitchen. It moistens dashimaki tamago (rolled omelet with stock folded in), gives chawanmushi (savory steamed egg custard) its silky texture, and forms the base of tsuyu, the dipping sauce for cold soba. Combined with soy sauce and mirin, it makes the gentle sweet-salty braise used for simmered vegetables and fish. Because the cuisine traditionally uses little oil or fat, flavor depends heavily on the stock.

Preparing dashi from scratch has become less common even in Japan. Granulated and liquid instant dashi largely replaced homemade versions in the second half of the twentieth century, and today many cooks use dashi packs, which work like tea bags. They are convenient, though they tend to taste stronger and less subtle than a stock made slowly. Many specialty shops and department store food halls still sell carefully made packs, and they make a sensible souvenir.

A Cuisine Recognized Worldwide

In December 2013, UNESCO added washoku, the traditional dietary culture of the Japanese, to its list of Intangible Cultural Heritage, noting its connection to the celebration of New Year. Principles at the heart of that tradition include respect for seasonal ingredients, separate bowls for separate dishes, and balance. Dashi quietly supports all of them, because it delivers depth without heaviness and lets seasonal ingredients taste like themselves.

Seen this way, umami is not a laboratory curiosity but a thread that runs through the whole meal. Fermented foods such as miso and soy sauce, dried seafood, mushrooms, and seaweed all contribute. When a meal in Japan feels unusually satisfying despite its simplicity, the effect usually has a name, and it was identified by a chemist who wanted to understand why a bowl of soup tasted so good.

Plan Your Visit

To taste dashi at its best, look for a teishoku (set meal) restaurant, a soba shop, or a kaiseki (multi-course) dinner where a clear soup is served. Many ryokan (traditional inns) offer a simple miso soup at breakfast that shows the stock clearly. Ask for the ichiban dashi in a suimono if you can. In Kyoto, Nishiki Market and department store food halls sell dried kombu, katsuobushi, and dashi packs in a wide range of qualities.

Prices vary, but a pack of everyday dashi bags can cost a few hundred yen (a few dollars), while premium kombu and block katsuobushi cost more. If you plan to bring dried fish products home, check your own country's import rules first. At home, steep kombu in cold water for a few hours and warm it gently, then add bonito flakes off the heat, and you will have a stock that tastes like Japan.