I find the “turtle-nose snake” case in the “Blue Cliff Record” helpful in feeling my jaw and skull in the balance of the body. Ch’an teacher Yuanwu offered the case (I’ll include only the first line):
‘Hsueh Feng taught the assembly saying, “On South Mountain there’s a turtle-nosed snake. All of you people must take a good look.”’
(Yuanwu’s commentary) … When Hsueh Feng speaks this way, ‘On South Mountain there’s a turtle-nosed snake’, tell me, where is it?
My late teacher Wu Tsu said, “With this turtle-nosed snake, you must have the ability not to get your hands or legs bitten. Hold him tight by the back of the neck with one quick grab. Then you can join hands and walk along with me.” (1)
The nose that came to mind when I read the case was a sea turtle’s nose—basically a pair of holes in a skull.
I find that awareness of the air moving through the holes in the skull behind the nose contributes both the dynamic of inhalation or exhalation and the balance of the head to the location of the center of balance.
Wu Tsu’s “join hands and walk with me”, I take to be a reference to an interaction between the placement of the arms and legs and the center of balance. Regarding “one quick grab”, I can only say:
I’m bound to be bitten by Wu Tsu, if I take his advice to mean there’s something I should do. It’s about realizing a cessation of “doing”, but I think I might run into him, in the stretch of ligaments. (2)
2) “Transition”, July 5, 2022, zenmudra.com/zazen-notes.