Nato is a traditional Japanese food made from soybeans fermented with Bacillus subtilis. It is popular especially as a breakfast food. As a rich source of protein and probiotics, nattō and the soybean paste miso formed a vital source of nutrition in feudal Japan. Nattō can be an acquired taste because of its powerful smell, strong flavor, and slippery texture. In Japan nattō is most popular in the eastern regions, including Kantō, Tōhoku, and Hokkaido.

The first thing noticed after opening a pack of nattō is its distinctive smell, somewhat akin to a pungent cheese. Stirring the nattō produces lots of sticky gossamer-like strings. The nattō strings themselves are often described by the Japanese ideophone nebaneba, which roughly translates as 'viscid' or 'gooey'. The flavor of nattō is nutty, savory, and slightly salty.

Nattō is commonly eaten at breakfast to accompany rice, possibly with, for example soy sauce, tsuyu broth, mustard, scallions, grated daikon, okra, or a raw quail egg. In Hokkaidō and northern Tohoku region, some people dust nattō with sugar. Nattō is commonly used in other foods, such as nattō sushi, nattō toast, in miso soup, tamagoyaki, salad, as an ingredient in okonomiyaki, or even with spaghetti or as fried nattō. A dried form of nattō, having little odor or sliminess, can be eaten as a nutritious snack. There is even nattō ice cream. Soybeans are sometimes crushed and fermented. This is called Hikiwarinattō. It is a food that is easy to digest.

The flavor of nattō can differ greatly between people; some find it tastes strong and cheesy and may use it in small amounts to flavor rice or noodles, while others find it tastes bland and unremarkable, requiring the addition of flavoring condiments such as mustard and soy sauce. Many non-Japanese find the taste unpleasant, while others relish it as a delicacy. Some manufacturers produce an odorless or low-odor nattō. The split opinion about its appearance and taste might be compared to Vegemite in Australia, blue cheese in France, surströmming in Sweden, lutefisk in Norway and Sweden, mämmi in Finland and Marmite in New Zealand, South Africa and the UK. Even in Japan, nattō is more popular in some areas than in others. Nattō is known to be popular in the eastern Kantō region (Tokyo), but less popular in Kansai (Osaka, Kobe). 236,000 tons of nattō are consumed in Japan each year.

Learn Mandarin, Kanji, and Hangul here