There are many small variations in
Shikantaza, teacher to teacher. One has to place and focus (and simultaneously
not place/focus) the mind somewhere!
So, for example, Uchiyama Roshi was a "
bring your attention back to the posture" guy. Nishijima Roshi is a "
focus on keeping the spine straight" fellow, and there are others who emphasize focusing on the breath or the
Hara (also called the "
Tanden", the traditional "center of gravity" of the body, and a center of Qi energy in traditional Chinese medicine) ...
http://en.wikipedia.org/wiki/Dantian
...
All are forms of
Shikantaza ... so long as the objectless nature of sitting is maintained even if focused on an object.
In fact, all forms of
Shikantaza have an "object of meditation", a place to focus or place the mind to build concentration and quiet the thoughts (hopefully to soften the border and pass through "object" and "subject"), while dropping all effort to attain and releasing all judgments. At Treeleaf, ... as our central "objectless" object of meditation, I recommend open, spacious sitting centered on everything and nothing at all ... sitting with open, spacious awareness ... sitting with the whole world but without being lost in trains of thought (which I also sometimes describe as having the mind focused on "no place and everyplace at once"). That open stillness is our "object of concentration". [
Jundo Note: In my view, our practice is not so much about keeping "one's mind on the here and now", but rather, about fully allowing the "here and now" so that the barriers of separation with the "here and now" drop away.] Another reason for that is that I believe it makes it a bit easier to take this practice off the Zafu and out into the world.