Miso soup is an ever-popular mainstay in Japanese cuisine. Although it is basically made of only miso and dashi stock, this versatile soup assumes many variations that reflect longstanding personal and family tastes.

Miso is a fermented paste whose ingredients are soybeans, salt and one of the following types of koji (fermentation starter): rice koji, barley koji, or soybean koji. The type and amount of koji used determine the character of the miso. There are also several varieties of dashi stock, such as katsuobushi dried bonito flakes, kombu and small dried anchovies or sardines. Pre-packaged, powdered dashi is commonly available, but some types of miso contain dashi, so the soup can be made simply by dissolving the paste in boiling water.

Miso soup is commonly prepared with one to two added ingredients, which may include preferred combinations of tofu, wakame seaweed, daikon, various mushrooms or asari clams—topped with chopped Japanese long onion or scallion. At home, heartier soups with multiple ingredients often accompany rice, making for a satisfying and nutritional meal. Miso soup recipe books offer inspiration for home cooks.