Cut the radish into 2cm thick slices.
Cut the tuna into bite-sized pieces.
Place the radish at the bottom of a pot and layer the tuna on top.
Add soy sauce, red pepper flakes, minced garlic, sugar, spicy chili pepper, black pepper, ginger, etc.
Pour in 200ml of water and cover with a lid. Bring to a boil.
Once it starts boiling, reduce to medium heat and simmer for 30 minutes.
When the sauce has reduced, taste and adjust seasoning as needed.