In a heavy pot, heat lard over medium-high heat until it melts. Add onion, sliced chili peppers, and sliced white scallion. Fry them gently in the hot fat, until they begin to brown slightly, 3 to 4 minutes. Stir occasionally.
Add garlic and ginger, stir continually until very aromatic, about 2 minutes. Take care not to let the aromatics burn. Ladle in warm broth, scraping up any bits of aromatics they may have accumulated on the bottom of the pan with your spoon. Bring to a light simmer, and add Korean pepper paste and flakes, fish sauce and honey. Stir, taste and add salt as needed. If it's a bit too spicy for you, tone it down with more honey.
Bring broth to a boil and add radish, shiitake, carrots, enoki and baby tatsoi. Once at a boil, decrease the heat to its lowest setting, cover, and then let it cook about 15 minutes. We want the vegetables to soften and add flavor to the broth.
Add the watercress and reserved green scallions. Bring back to a light simmer for 5 minutes, then lower the heat again.
Add shrimp and clams, cover and allow clams to open, and then add fish chunks. Careful not to overcook the seafood. Once the seafood is cooked, taste one last time, making any necessary adjustments for spice and salt.
Remove from heat, add garnishes, and serve with rice.