Soak the beef short ribs in cold water for 1 hour to remove excess blood.

Peel a yellow onion, chop it into quarters, and prepare garlic and ginger.

In a large pot, combine the soaked beef short ribs, ginger, quartered onion, and green onions with 10 cups of water. Bring to a boil.

Once boiling, reduce heat to medium, skim off brown foam, and maintain a clear broth.

Let the broth simmer uncovered for about 1 hour, stirring occasionally.

After 1 hour, add radish slices and simmer for an additional 20 minutes.

Discard onion and green onion pieces. Season with guk ganjang and sea salt to taste.

Serve the soup in bowls, garnishing with sliced green onions and black pepper.