Soak dried pollock (북어채) in a bowl with water and let it soak for a few minutes until slightly softened. Cut into bite-sized pieces if it’s not already cut properly. Reserve the soaking water—this adds a deep, savory flavor to the soup.
Slice the radish into 1cm thick half-moon pieces for a tender yet firm texture.
Cube the tofu into bite-sized pieces.
Slice the green onion into 2-3 cm pieces.
Heat a pot over medium heat and add 1 tbsp of perilla oil (or sesame oil). Add the sliced radish and soaked pollock and stir-fry for about 3 minutes until the radish becomes slightly translucent.
Pour in the reserved soaking water (about 5 cups). For a richer broth, add 1 anchovy soup stock tablet (optional). Bring the soup to a boil over high heat.
Once the soup is boiling, add the cubed tofu. Reduce the heat to medium and let it simmer for 20 minutes until the flavors deepen.
Taste the soup and season with Korean soup soy sauce (국간장) and salted shrimp (새우젓). Adjust the saltiness to your preference.
Add the sliced green onion and let it boil for 1 more minute.
Turn off the heat and serve the soup hot. Enjoy with a bowl of steamed rice and simple side dishes (banchan, 반찬).