Beat the eggs and set aside.
Bring katsuobushi (bonito) broth to a boil.
Cook the noodles in boiling water until done.
Rinse the cooked noodles in cold water and place them in a bowl.
While boiling the broth, slowly pour in the beaten eggs and stir gently.
Pour the egg broth over the noodles.
Finely chop green onion and sprinkle on top.