In Panshiguan there is a man by the name of Chen Yiyuan who abandoned his family to cultivate his mind in Daoist magic. He purchased a small house and spent his entire time locked up in complete isolation.
He started out refusing to eat rice or rice porridge, then he refused to eat fruit and vegetables as well, and finally his only sustenance was water from Lake Shihu. His son was responsible for bringing a jar of this water to the house each month, at which time he would find an empty teapot on the steps waiting to be filled.
One day a scholar by the name of Sun Jingzhai heard tell of this hermit. Filled with admiration at such remarkable resolve, he decided to see Chen in person. So he wrote a note requesting a meeting and left it on the lid of the teapot.
He waited anxiously for the reply, and the next day when he went to check the teapot he found a note added to the end of his own saying: "You have permission to see me on February the seventh."
Sun was ecstatic and on the appointed day he made his way to the house with Chen's son. When the door opened he was greeted by a man who didn't look a day over forty, though the son who had escorted him was already an old man.
Sun began to question the Daoist: "How should one begin to practice these Daoist arts?"
"First you must sit in a serene state and try to clear your mind of thoughts. You should keep tally of the number of thoughts that come into your mind," came the reply.
So Sun sat quietly for quite some time, until eventually Chen asked, "So how many thoughts came into your head?"
"I have had seventy-two different thoughts," Sun replied.
Chen laughed and said, "It is quite normal for one's mind to be active even though the body is still and one is trying to free the mind of thoughts.