In order to learn Zen you have to unlearn first. Nan-in, a Japanese master during the Meiji era (1868-1912), received a university professor who came to inquire about Zen. Nan-in served tea. He poured his visitor's cup full, and then kept on pouring.

The professor watched the overflow until he no longer could restrain himself. "It is overfull. No more will go in!" "Like this cup," Nan-in said, "you are full of your own opinions and speculations. How can I show you Zen unless you first empty your cup?" If you want to know the teachings of the Zen master, you have to empty what you have in your mental cup.

Zen practice developed in India as an offshoot of Buddhism. A Zen master from India, Bodhidharma of Mahayana stream of Buddhism is believed to have traveled to China where he met the Chinese Emperor Wu in 475 A.D. The emperor was Wu was deeply fascinated by Bodhidhrama