2tablespoonsKorean soup soy sauce, guk ganjang, 국간장 (see note)See note
salt and pepper to taste
Cut the beef into thin bite size pieces. Marinate with 1 tablespoon of soup soy sauce, 1 teaspoon of garlic, a pinch of pepper, and 1 teaspoon of sesame oil. Set aside.
Cut the radish into bite size pieces (1 to 1.5-inch square, about 1/4-inch thick). Cut the scallions into 1 to 1.5-inch pieces.
In a medium pot, sauté the beef until all the pieces turn brown. Pour in 8 cups of water and bring it to a boil. Skim off the foam. Reduce the heat to medium high and continue to boil, covered, for 10 minutes.
Add the radish pieces and boil, covered, until the radish turns translucent and soft, 10 to 15 minutes. Stir in the remaining teaspoon of the garlic, scallions, and the remaining tablespoon of the soup soy sauce. The soup should not look too dark. Taste for salt and pepper. Boil for an additional 5 minutes.
Do not substitute with regular soy sauce. It will be too sweet and dark. A better substitute is fish sauce, which is sometimes used in Korean soups.