Quote:
"In an ancient text ascribed to Bodhidharma, his way of meditation is characterized by the Chinese word pi-kuan, literally wall-gazing or wall-contemplation. Except for the word pi-kuan, the same passage is found in a Mahayana sutra; it reads: "When one, abandoning the false and embracing the true, in simplicity of thought abides in pi-kuan, one finds that there is neither selfhood nor otherness, that ordinary men (prthagjana) and saints (arya) are of one essence." (Zen Enlightenment, p. 38).
The actual meaning of "wall gazing" may not be a literal "sit while gazing at a wall", but closer to "sit as if a wall seeing". Nobody really knows what the term originally meant however. The great Zen Historian Yanagida Seizan has (ala Shikantaza) interpreted the term to denote a sort of witnessing of the world with the steadfast detachment of a wall in which one “gazes intently at a vibrantly alive śunyatā (emptiness).”