Those familiar with Japanese background or culture might have seen some version of a komusō, or “priest of nothingness.” Instantly recognizable (and simultaneously unrecognizable) thanks to this woven baskets they use over their heads and the long flutes that protrude from beneath them, these Buddhist monks were exceptional for a number of obvious reasons. But it is their haunting meditation melodies which could be their most enduring legacy.

The komusō, also occasionally interpreted as “monks of emptiness” or something similar, came to prominence across the 17th century Japan, and formed a new category of itinerant monks, of the Fuke sect of Japanese Zen Buddhism. The komusō, which only allowed in men of the samurai or ronin class, utilized the shakuhachi as a religious instrument, in contrast to the quietude or recited mantras that other sects utilized in meditation. The Fuke sect monks rather played compositions called honkyoku to focus their minds toward enlightenment; they called it suizen, or “blowing zen.” According to the dictates of the sect, the shakuhachi was played only for meditation or for alms, rather than with other instruments, so listeners can concentrate only on the sound of the flute. The leading compositions are spare and haunting pieces of tonal music.

The komusō also embraced their distinctive woven wicker hat or mask, known as a tengai, which resembles an overturned basket with slits for the monks to see out of. Wearing one traditionally represented a dismissal of ego or self, although the masks hid the identity of the wearer. Many of the komusō were ronin, or wandering samurai, trying to begin a new life with all the anonymity the apparel supplied.

From the time they banded together as the Fuke sect in the 1700s, the komusō had been awarded exceptional specific privileges by the ruling powers. The shogun Tokugawa Ieyasu allegedly passed a decree in the early 17th century which enabled komusō unrestricted traveling in feudal Japan, when free movement across boundaries was highly limited. Although this decree was most certainly forged, it had been admired and added to for years.

One addition to the decree awarded the monks exclusive use of the shakuhachi, which made the flute a effective passport and status symbol. By the first 1700s some komusō started teaching laymen to perform for a fee–that opened the door for new styles of secular shakuhachi songs to emerge, also dampened the novelty of the komusō over the next century.

The anonymity and freedom provided by the tengai also meant that outlaws, spies, and thugs eventually traveled beneath the guise of a komusō (those long bamboo flutes doubled as good clubs). This finally made the people suspicious of anybody wearing the woven masks, also some towns banned the traveling performers altogether.

By the time that Buddhism came under attack in Japan in the 1870s, the komusō were already on the wane. And if the Fuke sect was outlawed at this time, playing the shakuhachi became a purely secular endeavor.

Their musical heritage survives now, through reenactments and shakuhachi performances. Most of the original compositions that still exist thanks to komusō Kinko Kurosawa, who wrote and collected some 36 honkyoku from the early 1700s. These compositions form the basis of a type of shakuhachi performance called the Kinko Ryū, which epitomizes the sound of period komusō flute.

Today, you will find a few surviving shakuhachi disciplines, and the indelible image of the basket-headed komusō are available popping in popular culture, from anime to film. But while their eccentric look is hard to overlook, the effect of the signature flutes is truly worth remembering.