I found this soup to be a little boring. My bonito might have been part of the problem. I had my bonito flakes in the pantry for a while but they were individually packaged so I thought they were still ok but maybe they had lost some of their flavor. I substituted instant miso since that's all my grocery store had. I also added a few slices of shiitake mushrooms and I liked the extra texture. If I made this again I would add some green onions.
Very easy to make and so good for you!