Most Zennists recall this famous saying of Qingyuan Weixin (9th-c) who said:
“Before I had studied Zen for thirty years, I saw mountains as mountains, and waters as waters. When I arrived at a more intimate knowledge, I came to the point where I saw that mountains are not mountains, and waters are not waters. But now that I have got its very substance I am at rest. For it's just that I see mountains once again as mountains, and waters once again as waters.”
Zennists in their nursery school phase of Zen think they are pretty smart. They carefully read the words of Qingyuan, which seem not too difficult to understand, and because they also see mountains as mountain again and water again as water, they feel that they understand Qingyuan. But this is not where Qingyuan is coming from. Remember, it took him 30 years to reach the third stage.
Being smart in Zen is different than being smart at cards or building a house, or doing mathematics. Smart in Zen means seeing the unconditioned while being immersed in the conditioned.
Permit me to make it even more simple. Being smart in Zen is like seeing a gold Buddha statue and being able to distinguish the gold from the Buddha image. The Zennist knows, “This is gold; this is the shape,” and with enlightenment, “This is the Mind substance; all this is a configuration of Mind.” The last part is, of course, the Buddha’s enlightenment in which we have got its very substance; seeing the very unconditioned substance of reality and, furthermore, seeing it as mountains and water. This I hasten to add is being Zen smart.
So, what is key in Qingyuan’s words? Its very substance. Smart Zennists strive to see this very substance which might take them thirty years.