Wash the perilla leaves thoroughly, remove excess water, and trim the stems to leave about 1 cm.

In a pot, combine water, soy sauce, and sugar. Bring to a boil, then add vinegar and turn off the heat.

Slice garlic, green chili, and red chili thinly. You can omit these if preferred.

In a storage container, layer 5 perilla leaves, then add a small amount of garlic and chili. Repeat until all leaves are layered.

Pour the soy sauce mixture over the layered leaves and close the lid. After 30 minutes, flip the leaves for even pickling.