Gather napa cabbage, Korean radish, salt, garlic, ginger, scallions, gochugaru, fish sauce or salted shrimp, and sugar
Cut the cabbage lengthwise into quarters
Remove the core and cut into bite-sized pieces
Rinse the cabbage
Salt the cabbage thoroughly
Let it sit for 1 to 2 hours, turning occasionally
Rinse the cabbage several times
Drain well
Make a paste with garlic, ginger, gochugaru, fish sauce or salted shrimp, and sugar
Add grated radish and chopped scallions to the paste
Mix the cabbage with the paste until evenly coated
Pack the kimchi tightly into a clean jar or container
Press down to remove air pockets
Leave some space at the top
Close the container loosely
Let it ferment at room temperature for 1 to 3 days
Check daily and press down if needed
Move to the refrigerator when it reaches the desired sourness
Store chilled and serve cold