Ashikaga Indigo is a traditional dyeing technique from Ashikaga City in Tochigi Prefecture, Japan. It uses only natural materials—such as indigo leaves and wood ash—and relies on a fermented dye solution to produce its rich blue hues. Known for its deep, authentic color, Ashikaga Indigo is used on clothing, masks, and various other items, preserving a centuries-old tradition rooted in natural craftsmanship.