Soak Perilla Leaves: Dissolve 1 teaspoon of salt in water and soak the perilla leaves for 2-3 minutes. Rinse thoroughly with running water.
Prepare Leaves: Remove excess water from the leaves and trim the stems, leaving about 1 cm.
Blanch Leaves: Add a pinch of salt to boiling water and blanch the perilla leaves for 30-40 seconds. Cool in a strainer.
Prepare Chilies: Remove stems from the chilies, cut them open, remove seeds, and slice diagonally.
Make Soy Sauce Mixture: In a pot, combine soy sauce, water, sugar, and dried kelp. Bring to a boil, then remove kelp and add vinegar.
Combine Ingredients: In an airtight container, layer blanched perilla leaves and chilies, then pour the cooled soy sauce mixture over them.
Weight Down and Rest: Place a heavy plate or stone on top to ensure the leaves are submerged. Let it rest for half a day.