If you're having trouble grasping the concept of zen, try this: cover your hands with glue. Grasp a pencil very tightly. Is that pencil like zen? No, it's not. Is the following koan like zen? At least as much as a pencil, yes.
Kasan was asked to officiate at the funeral of a provincial lord.
He had never met lords and nobles before so he was nervous. When the ceremony started, Kasan sweat.
Afterwards, when he had returned, he gathered his pupils together. Kasan confessed that he was not yet qualified to be a teacher for he lacked the sameness of bearing in the world of fame that he possessed in the secluded temple. Then Kasan resigned and became the pupil of another master. Eight years later he returned to his former pupils, enlightened.
The enlightenment: Kasan would have mistaken a stick of Right Guard for enlightenment. He never really "got" the whole zen thing, but we kept him around cause he made good stew.