Remove the roe from the mentaiko by making a slit.

Cut the Chinese cabbage, mizuna, and silken tofu into bite-sized pieces. Trim the root of the shimeji mushrooms and separate them by hand.

Cut the chicken thigh into bite-sized pieces and grate the nagaimo.

In a pot, mix the broth ingredients (sake, sugar, soy sauce, dashi powder, and water) and heat over medium heat. Add the chicken and cover. Skim off any foam that forms.

Add the Chinese cabbage, shimeji mushrooms, and silken tofu. Cover and simmer for 5 minutes.

Add the mizuna and top with grated nagaimo. Cover and heat for 2–3 minutes.