The Zen Buddhist "Okyos" are sung on one note in order to visualise them beyond all emotion. The "okyo" is understood primarily as a phonetic experience, as a sound event that puts the understanding of the content of the texts in the background.

"For years, my Okyo meditations consisted of improvisational practice processes about the inner life of the tones. Every day for many hours I observed the sound singing, how it went into itself and out of itself." (Michael Vetter)