A shakuhachi is a Japanese and ancient Chinese longitudinal, end-blown flute that is made of bamboo.
During the medieval period, shakuhachi were most notable for their role in the Fuke sect of Zen Buddhist monks, known as komusō (‘priests of nothingness’ or ‘emptiness monks’), who used the shakuhachi as a spiritual tool. Their songs (called honkyoku) were paced according to the players’s breathing and were considered meditation (suizen) as much as music.
Several particularly difficult honkyoku pieces, e.g. ‘Distant Call of the Deer’, became well known as ‘tests’: if one could play them, they were a real Fuke monk. If they could not, they were probably a spy and might very well be killed if they were in unfriendly territory.