Make chicken stock by cooking chicken breasts in 8 cups boiling water and 2 teaspoons salt. Cook in boiling water for 10 minutes, (add dried scallops here if you like) then lower heat and cook for about 30 minutes. While making stock, wash and drain all vegetables. Cut mizuna into 2 strips (you won't need much of this-just to add green color). Slice the kamaboko fairly thin. Put a few mochi into toaster and toast until puffy.
Remove chicken from stock onto a plate. While chicken is cooling, strain the soup in either cheesecloth or some kind of cloth to strain* to a clean pot. Add the carrots and daikon and cook until tender (about 10 to 15 minutes). (Shred 1 breast of chicken and add to broth. Save the rest to make chicken salad or whatever for another time.) Check flavor and add salt if needed. Just before serving, put mizuna in soup just to parboil-must be crunch/crisp. Put toasted mochi in a bowl, pour the soup over mochi, then put several slices of kamaboko on top and serve.
*I prefer using old restaurant linen because it strains better!