The tenugui (手ぬぐい) is a lightweight cotton cloth that has been part of Japanese daily life since at least the Heian period. Traditionally used for wiping, wrapping, and carrying objects, it was later incorporated into martial practice as a headwrap worn beneath helmets to absorb sweat and improve comfort. Often decorated with patterns, symbols, or dojo names, tenugui also function as expressions of identity and affiliation. Its continued presence in martial arts reflects the enduring role of simple, multifunctional objects within Japanese cultural tradition.