Cut the napa cabbage in half lengthwise, then slice into 2 cm wide pieces.

In a bowl, mix the oysters with potato starch. Add enough water to cover and gently wash the oysters. Replace the water until it runs clear, then drain and pat dry with a paper towel.

In a pot, combine the soup base ingredients (consomme, salt, pepper, and water) and heat over medium heat. Once boiling, add the napa cabbage. Bring to a boil again, cover, and simmer on low heat for about 5 minutes until the cabbage softens.

Add the oysters to the pot and increase to medium heat. Once boiling, cover and cook for 1-2 minutes until the oysters are cooked through.