Chop the green onion into small pieces.

Cut the tofu into bite-sized pieces.

Lightly beat the egg in a small bowl.

In a pot, add water and kombu, and bring to a boil over high heat.

Once boiling, continue to boil for 7 minutes, then remove the kombu.

Season the broth with salt and soy sauce. Taste and adjust seasoning if needed.

Add the tofu to the broth and let it cook until it floats to the surface.

Pour the beaten egg into the soup in a circular motion.