Wash radish, onion, green onion, and garlic thoroughly and cut them into large pieces.
Pour water into a pot and add the prepared ingredients along with kelp and shiitake mushrooms.
Boil over medium heat for 20 minutes.
Remove the kelp after 10 minutes.
Strain the broth to make it clear, extracting the flavors from the vegetables.
Season with soy sauce, salt, etc.