Like soysauce Dashi is an essential item for Japanese cooking. For example , we use it for miso soup and I eat it everyday. Dashi is soup stock that is extracted by dry shaved bonito "Katsuobushi" , small fish "Niboshi" or kelp "Konbu" . This is an example of "Umami".
Japanese usually say that Dashi is the most important element for Japanese food .(Dashi ga Inochi .)