One day the Fifth Patriarch Hongren challenged his monks to compose a gatha that expressed their understanding of the dharma. If any verse reflects the truth, Honggren said, the monk who composed it will receive the robe and bowl and become the Sixth Patriarch.

However, the disciples said to each other that they didn't need to write any gathas, and that surely head monk Shenxiu would become the Sixth Patriarch. As a result, only Shenxiu wrote a gatha: 

      The body is a Bodhi tree,
      The mind a standing mirror bright.
      At all times polish it diligently,
      And let no dust alight.

Hearing the gatha, Huineng immediately knew it lacked true insight. He asked a district officer to write a poem of his own for him next to Shenxiu's, which stated:

      Bodhi originally has no tree.
      The bright mirror also has no stand.
      Fundamentally there is not a single thing.
      Where could dust arise?

This gatha created a bigger stir, and everyone was amazed. When the alarmed Hongren came out, he just casually said, "This hasn’t seen the essential nature either," and proceeded to wipe the gatha off with his shoe.

The next day, under cover of darkness, Hongren received Huineng in his abode, and expounded the Diamond Sutra to him. When he came to the passage, "to use the mind yet be free from any attachment," Huineng came to great enlightenment—that all dharmas are inseparable from the self nature. Then Huiren passed the robe and bowl as a symbol of the Dharma Seal of Sudden Enlightenment to Huineng.