Akadashi miso soup is a miso soup made from a blend of Hacho-style (soy bean and rice) miso paste. Alternatively it is altered from being made of a base of soy bean and rice miso to being made by combining seasonings (kelp and bonito flake stock). It is mainly produced in the Tokai and Kyoto regions.
Originally it was altered depending on the ingredients used in the miso soup.
By decreasing the proportion of soy bean miso and increasing the rice miso it is called by a different name 'awase miso' (blended miso).
Actually, most of the miso soup eaten in the Nagoya region is called 'Akadashi.'
When sushi restaurants list 'Akadashi' on the menu, what is meant is 'miso soup.'