In the Sûrangama Sûtra, which has had a significant influence upon the Zen Buddhist tradition, the Bodhisattva Avalokitesvara (Jap. Kannon 観音, literally 'Seeing Sound'), the 'One Who Hears the Sounds of the World', describes how she attained enlightenment by initially meditating on hearing and sound. Zen master Xiangyan Zhixian (香厳智閑, J. Kyôgen Chikan, ca. 9th C.) attained enlightenment upon hearing the sound of a pebble hitting a bamboo while sweeping the ground. Wumen Huikai (無門慧開, J. Mumon Ekai, 1183-1260) was awakened as he heard the sound of the drum that announced mealtimes. Hakuin Ekaku (白隠慧鶴, 1686-1769), was enlightened by the sound of the temple bell announcing dawn as he was meditating through a winter's night. One monk experienced awakening with the clattering of a tile breaking on the ground. The sound of honkyoku being played on a bamboo flute is the sound of enlightenment itself.
-Shakuhachi