The first anecdote involves a disciple of Hui-neng's Nan-Yueh Huai-jang 南嶽懷讓(677-744). Huai-jang observed a monk named Ma-tsu 馬祖 (709-788) who had a habit of doing tso-ch'an all day long. Realizing this was no ordinary monk, Huai-jang asked Ma-tsu, "Why are you constantly doing tso-ch'an?" Ma-tsu answered, "To attain Buddhahood." Huai-jang picked up a brick and started rubbing it vigorously. After a while, Ma-tsu asked, "What are you doing?" Huai-jang said, "I'm making a mirror from this brick." Ma-tsu said, "That's absurd. You can't make a mirror from a brick." Huai-jang said, "Indeed. And how is it possible to become a Buddha by doing tso-ch'an?" Thereupon, Ma-tsu asked, "What should I do?" Huai-jang said, "When the ox won't pull the cart, do you beat the cart or the ox?" Ma-tsu did't know how to reply. So Huai-jang said, "Are you doing tso-ch'an to attain Ch'an or to become a Buddha? If it's Ch'an, Ch'an is neither sitting nor lying down; if it's Buddhahood, the Buddha has no form. Since the Dharma has no abiding form, there should be no grasping, nor rejection. Being attached to sitting, not only are you not becoming a Buddha, but you are killing the Buddha." Ma-tsu became a disciple of Huai-jang and later, a great master.

The meaning of this story is that true tso-ch'an is not just a matter of sitting, however perfected and dedicated. Some people may do tso-ch'an in this way and may get some benefits. But to attain Ch'an by perfecting the external form, or the physical aspect of tso-ch'an is impossible. Enlightenment begins with introspection, in what Huai-jang 懷讓 called hsin-ti 心地, the method of the mind-ground. The word "ground" is used here to mean "everything can grow form this ground." Thus, self-nature is to be found not in the realm of form, nor through self-cultivation, but in the mind-ground.

Ma-tsu 馬祖 himself later evolved the concept of p'ing-ch'ang hsin 平常心, or "ordinary mind." One sense of Ma-tsu's "ordinary mind" is mind which is involved in the ordinary world, and moves as usual, but is not attached to anything. Another sense comes from the root meanings of the words p'ing 平 and ch'ang 常, and can be construed to mean a mind which is "level" and "constant", that is, in a state of constant equanimity. In either sense, there is no attachment. So the point is, the kind of tso-ch'an that Ma-tsu did before he met Huai-jang emphasized physical aspects at the expense of being grounded in mind.