Cut fish cakes, radish, green onion, and onion into bite-sized pieces.
Pour water into a pot and make broth with anchovies and kelp.
Once the broth is ready, remove the kelp and anchovies.
Add radish and onion and bring to a boil.
When the radish is half-cooked, add the fish cakes and boil again.
Season with soy sauce and salt.
Add green onion and spicy chili pepper, and boil once more.