Wipe the kombu gently with a damp cloth to remove impurities.

Add all ingredients except kombu into a pot and boil over medium heat until bubbles appear.

Add kombu and reduce to low heat, simmer for 10–15 minutes.

Strain the mixture to separate solids, reserving some shiitake mushrooms for later use.

Preheat a frying pan and cook beef brisket over medium heat until done.

Add radish to the pan and sauté for 3 minutes until slightly softened.

Add 1 tbsp all-purpose soy sauce and simmer briefly.

Add water and another 1 tbsp soy sauce to the pan and bring to a boil.

Cook noodles in boiling water until al dente.

Rinse cooked noodles under cold water and drain thoroughly.

Add prepared vegetables and reserved shiitake mushrooms to the broth and cook until tender.

Warm the serving bowl by pouring hot broth over the noodles and draining it back into the pot.

Pour beaten egg into the boiling broth and cook until set.