What is dashi?
Dashi is the Japanese word for stock. Japanese dashi is light but packed with umami. It's made by soaking dried edible kelp (kombu), cured bonito flakes, and sometimes dried sardines or dried shiitake mushrooms in water.
These ingredients can be soaked more than once. The stock from the first soaking, the ichiban dashi, has the finest flavor and is mixed with a little miso paste to make miso soup. The second stock made by resoaking the ingredients is called niban dashi, and is used for making noodle soups or dishes with more ingredients or stronger flavors.
Instant dashi powder can be bought in Japanese grocers, but it's easy enough to make at home.
Recipe: Basic Dashi (Cookthink)
Recipe: Miso Soup With Tofu And Soybeans (Cookthink)