"Blood . . . yes, even blood." and the Zen Master (excerpt from Guru I, Cabeza):

. . . Second, at sesshin if you are one of the ardent elite, you stay up most of the night sitting, especially the last nights. And, I was told, if you’re one of the elite of the elite, you are a member of the “Graveyard Shift.” First I must explain the kyosaku, the three-foot, flat-bladed stick with which you were struck—either at your signal or their discretion—by the monitors on the fleshy area between the neck and shoulder blade. This was supposed to propel you deeper into your sitting. (I must admit that once, and only once, it did actually do so for me. Most of the time I found the whack-whack-whacking sound a severe distraction.) The Graveyard Shift was reputed to stay up all night in the attic of an adjoining building whacking themselves so hard and so much that the blood flowed. While I cannot testify to the veracity of this, I can quote from a pep talk of Kapleau’s given at this time and printed in the Autumn 1975 Zen Bow. “Unless in your own striving . . . you have passionately struggled . . . as the sweat, tears and blood—yes, even blood—flowed,” then you might as well pack it in. Or out. Or wherever.
    In another pep talk Bodhin said, “Pain is a great teacher.” (Sitting, especially cross-legged, the number of hours one does at a sesshin can become quite physically painful.) I do not deny this. But. I don’t know for sure as I can’t get in others’ minds, but I strongly suspect that all that externally applied pain until “the blood flowed” was just a distraction from the inner pain and fear that is never faced. To prevent one from ever facing that inner pain and fear. To keep it from ever coming into consciousness. I believe I am right at least as far as Kapleau, Harada, and Yasutani Roshi were concerned, and at least some of the Center’s members. Anne was told by someone at the Montreal affiliate, “It [enlightenment] doesn’t change anything.” I’ve read others write as much in magazines I’ve browsed at our Buddhists’. Meaning the same old wanting and fearing were there for that person. Is it like taking mescaline or LSD and it’s great while the memory lingers, but eventually . . . ? 
    And then, then there was Toni. 
    Toni Packer. . . .