Hi Andrew,
Let me start at the end:
Historian Morten Schlutter has chronicled the history of Silent Illumination Zazen (in his masterful "How Zen Became Zen", p. 172-174):
Awhile back, I posted quotes from several of the old Chinese masters that seem on point. I will provide the links, and a taste of each:
The Zazen taught in the 'Platform Sutra' is Shikantaza
Hui-neng teaches that Zazen is not about "stilling the mind" to have no thoughts, but about "non-thought, non-form, non-abiding", i.e., freedom from thoughts, form and abiding even amid thoughts form and abiding ... the heart of Shikantaza. Notice in the following that the problem is --not-- that "successive thoughts stop", but only that we do not cling to them:
... In case there is any doubt, this Zazen is seated Zazen ... but sitting unentangled by the forms seen outside through the open eyes, inwardly clear. It is --not-- to be without thoughts, but not to activate them, to pursue and become entangled. The very act of sitting is pure:
https://www.treeleaf.org/forums/show...ll=1#post61069
It is not surprising that the meditation style of the Platform Sutra smacks of Shikantaza, as Shikantaza smacks of Silent Illumination ... and such was pretty much the orthodox style of many of the early Chan masters, such as Sekito Kisen (Shitou Xiqian), just two generations from the 6th Patriarch.
Bodhidharma:
Even Master Linji. It is clear that meditation happened in his monastery, but he seemed to emphasize so with a "non-gaining" mind and a "non-learning" meditation of just "turning the light withing":
Andrew, you ask:
Well, not really. The "enigmatic sayings" in the Koans were typically written by later authors of the Song dynasty about figures who lived in the earlier Tang dynasty, and are mostly not considered historical records of events, and instead literary creations. As you can see, the earlier documents such as the Platform Sutra, Record of Rinzai and the like are comparatively easy to understand and are not in the style of "enigmatic phrases."
No. It is pretty clear that the meditation was part of the daily schedule at almost all Chan monasteries from the practice rules we have. There were statements, just as by Linji, against meditation done with gaining mind ("shuzen" or "learning meditation," the same criticism Dogen makes in the Fukanzazengi.) In fact, government authorities would have closed down any monastery viewed as so "lax" as to not be keeping the traditional monastic schedule. There is a good historian's paper on this which I will try to find for you.
No. Almost no teachers of the past held that one was fully awakened by one opening experience.
Sorry, I don't understand the question.
Yes, there was a heavy Taoist influence, specifically from neo-Taoist Xuanxue practices and sensibilities, which perfumed Indian Buddhism to become Chan.
Do you have other concerns?
Sorry for writing long.
Gassho, Jundo
STLah