An update to the Archive post The Mirror Image after reading of a debate using the simile of the mirror between two contenders for the title of the Sixth Patriarch of the Zen sect by D.T. Suzuki, found in the JPTS 1906. Suzuki writes:
"An interesting story is told of the sixth patriarch, Hui Neng — how he came to succeed Hung Jen in his religious authority. The fifth patriarch wished to select his spiritual heir among his many disciples, and one day made the announcement that anyone who could prove his thorough comprehension of the religion would be given the patriarchal robe, and proclaimed as his legitimate successor. According to this, one of his disciples, who was very learned and thoroughly versed in the lore of his religion, and who was therefore considered by his brethren in faith to be in possession of an unqualified right to the honour, composed a stanza expressing his view, and posted it on the outside wall of the meditation hall, which read:
This body is the Bodhi-tree;
The soul is like a mirror bright:
Take heed to keep it always clean,
And let not dust collect on it.
"All those who read these lines were greatly impressed, and secretly cherished the idea that the author of the gatha would surely be awarded the prize. But when they awoke next morning, they were surprised to see another written alongside of it, which ran as follows:
The Bodhi is not like the tree;
The mirror bright is nowhere shining:
As there is nothing from the first,
Where can the dust itself collect?
"The writer of these lines was an insignificant monk, who spent most of his time in pounding rice for the brotherhood. He had such an unassuming air that nobody ever thought much of him, and therefore the entire monastery was now set astir to see this bold challenge made upon its recognized authority. But the fifth patriarch saw in this unpretentious monk a future leader of mankind, and decided to transfer to him the mantle of his office.
This event is stated to have occurred in 675 AD. The author of the first stanza is not named. His error is in identfying the self as the mirror. Hui Neng's response contains the error of denial of the self. Both are the error of taking a stand on a point of view, 'ditthi.' The two stanzas ... um ... reflect each other in another ...er... reflection of the idea of the mirror: reflecting opposites. This is my response (a few hundred years late, I admit, but still, I think I have a legitimate claim to the title of sixth patriarch).
Awakening is not Like,
or any Thing of Us.
The Body, the Bodhi Tree,
It's ripe fruit, the mirror free of Dust,
Consumed such fruit no longer do We see.
 Journal of the Pali Text Society, Volume V, 1906-1907, p.8, The Zen Sect of Buddhism, by Daisetz T. Suzuki.