Suizen or blowing Zen

Suizen Gyouke Seiganmon (Vow)

Blow once to exorcise all bad things:
Blow a second time to master all good things:
Blow a third time to save all people:
Thus everyone can attain Buddhahood. from "The guidelines of Myoan Temple"

Hotto established suizen of "Blowing Zen meditation" after realizing that blowing shakuhachi is an excellent means of meditation. In this way, Myoan Shakuhachi occupies a completely different dimension from other musical environments.

In Myoan Shakuhachi, one sound is produced by blowing "wedge" style (kusabi-buki). That is to say, the sound changes as one exhales. In accordance with certain breathing techniques in Zen training, blow the air out one time, in the wedge style blowing, one sound is completed by changing the tone in the afterglow of "tsu", "re", "u", etc., ... producing an "unrhymed rhyme". One "song" is constructed by building auditory exhalations one by one.

Moreover, the shakuhachi is regarded not merely as a secular musical instrument, but as ritual tool so that "Jinashi one shaku eight sun" (a shakuhachi not lined with powdered stone) is regarded as the authentic instrument which evokes the spirit of the original bamboo sound (ne-aji) which comes from unprocessed bamboo.

Likewise, blowing Zen is not to be displayed in public since it is equivalent to Zen meditation.

Source ~ https://myouan-doushukai.org/en.html