Menzan Zenji and Katagiri Roshi on "The Disruptive Point of Zazen"
"The immediate manifestation of dropping off body and mind removes sickness inside and outside." - Menzan

Below you will find a poem on the "The Disruptive Point of Zazen" (坐禪箴, Japanese, Zazenshin) by Menzan Zuiho (1683-1769), translated by Katagiri Roshi, followed by Katagiri Roshi's brief commentary.
The above two masters are perfumed with the teaching of two earlier masters - Hongzhi (1091-1157) and Dogen (1200-1253) who both left us poems titled Zazenshin. Dogen's version is still recited by practitioners like us in our personal morning service and then dedicated to our practice teachers. It is part of a longer fascicle by the same title that unpacks the subtle practice-verification process of zazen.
Menzan was an influential Zen monk and scholar during the reforms of the Tokugawa period. Menzan's passion was to return to the original spirit and letter of Dogen's teaching. He was part of the revitalization of the Soto school that gradually came to feature interest in Dogen's written works as something to be studied, rather than temple talisman.
Menzan wrote a commentary on each of the 75 fascicles of Dogen's Shobogenzo, including the Zazenshin poem that follows.
Menzan's Zazenshin
Shin 箴 is an instrument to cure sickness.
Here it means to kill the sickness of Zen.
This sickness is chronic and obstinate.
The immediate manifestation of dropping off body and mind
removes sickness inside and outside.
This is vigorous and sound wisdom.
Right and wrong views are originally empty.
The sickness of Dharma can be diligently cleansed and removed.
A bird flies like a bird, a fish swims like a fish.
Seeing and hearing are much clearer.
Sound and form are as-it-isness.
The intent of Buddha and the intent of becoming Buddha go beyond.
Three times and ten directions are hard to separate.
Katagiri Roshi's comment
"Just switch your attention back to this center, embracing the total picture of zazen itself - including thinking, not thinking, and nonthinking - without meddling. Then you can directly perceive the nature of the perpetually wandering world.
"This awareness is not a mental experience created by your consciousness. Body and mind directly realize it. Sometimes the realization is strong and sometimes it is more subtle and smooth. Someday you can taste it."