From an email to Karan Vasudeva, author of the article Adventures at the Vipassana Enlightenment Factory :
(Concerning the “dan-t’ien”:) I write about the mind shifting to the dan-t’ien, but not shifting the mind to the dan-t’ien. My experience is following the location of awareness in three-dimensional space, as opposed to noting the object in awareness. Being mindful of the location of awareness is “turning the lamp around”, or “taking the backward step”, in the nomenclature of Zen.
It’s also possible to just keep the focus on the center of balance, but there’s an implied effort in that, whereas staying with the location of awareness is just acknowledging where I am. As Yuanwu, the author of the “Blue Cliff Record”, said:
Be aware of where you really are 24 hours a day. You must be most attentive.
(“Zen Letters: the Teachings of Yuanwu”, tr. Thomas Cleary, pg 53)
Right now I seem to have to engage in a juggling act some of the time, just to breathe freely. That would involve the length of the inhalation or exhalation, the location of awareness, and the counter-balance of the location of awareness that originates with contact in the senses (including proprioception and graviception).
Sometimes the counter-balance of the location of awareness originates with contact from beyond the range of the senses. Gautama spoke of extending the mind of friendliness through the four quarters of the world, above and below, and in my experience such an extension opens the door to contact from beyond the conscious range of the senses.
I mentioned that it’s possible to keep the focus on the center of balance. The weight of the body at the center of balance generates stretch and activity, and that activity returns to counter-balance the weight of the body. Familiarity with the particulars of stretch and activity allows for some ease in the process, and yet the effort of focus on the center of balance as opposed to staying with the location of awareness can impinge on the spontaneous movement of breath.
Gautama spoke of comprehending the length of a given inhalation or exhalation, and I have found such comprehension to be a necessary part of my “juggling”, but Dogen’s teacher Rujing discarded such comprehension in favor of a particular experience with regard to the “tanden” (dan-t’ien):
Breath enters and reaches the tanden, and yet there is no place from which it comes. Therefore it is neither long nor short. Breath emerges from the tanden, and yet there is nowhere it goes. Therefore it is neither short nor long.
(“Eihei Koroku”, Dogen, vol. 5, #390, tr. Okumura)
Sometimes the breath has to enter and emerge from the tanden in order to move at all, in the midst of ongoing activity of posture or carriage. Nevertheless, to focus awareness at the tanden rather than to follow the location of awareness is to run the risk of ending up “unwilling to dismount having once mounted the donkey”, as Zen Master Foyan put it:
In my school, there are only two kinds of sickness. One is to go looking for a donkey riding on the donkey. The other is to be unwilling to dismount once having mounted the donkey.
… I tell you that you need not mount the donkey; you are the donkey!
(Foyan, “Instant Zen: Waking Up in the Present”, tr. T. Cleary, pg 4)
I would say there’s a happiness associated with the free movement of inhalation and exhalation, and the experience of that happiness sometimes requires both a relaxed one-pointedness of mind and a calm alertness of the senses.
Gautama, whose “way of living” was mindfulness pegged to inhalation or exhalation, spoke of experiencing “nothing but happiness” in a conversation with a member of the Jain sect:
“…What do you think about this, reverend Jain: Is King Seniya Bimbisara of Magadha, without moving his body, without uttering a word, able to stay experiencing nothing but happiness for seven nights and days?”
“No, your reverence.”
… “But I, reverend Jain, am able, without moving my body, without uttering a word, to stay experiencing nothing but happiness for one night and day. I, reverend Jain, am able, without moving my body, without uttering a word, to stay experiencing nothing but happiness for two nights and days, for three, four, five, six, for seven nights and days.”
(“Cujadukkhakkhandhasutta”, MN I 94, Pali Text Society Vol I pg 123-124)