In the pursuit of the Way [Buddhism] the prime essential is sitting (zazen). . . . By reflecting upon various 'public-cases' (koan) and dialogues of the patriarchs, one may perhaps get the sense of them but it will only result in one's being led astray from the way of the Buddha, our founder. just to pass the time in sitting straight, without any thought of acquisition, without any sense of achieving enlightenment -this is the way of the Founder. It is true that our predecessors recommended both the koan and sitting, but it was the sitting that they particularly insisted upon. There have been some who attained enlightenment through the test of the koan, but the true cause of their enlightenment was the merit and effectiveness of sitting. Truly the merit lies in the sitting.

(The Shobo Genzo)