Muso Soseki was a 14th c. Japanese Zen master, poet and designer of meditative gardens. ‘The Sixth Patriarch’, mentioned in this poem, is the Chinese Chan master Hui Neng, who was a fountain of inspiration for Japanese Zen Buddhism.

The water that can’t be muddied
     with any stick
          is deeper than depth
The sky and the water
     are a single
          deepening blue
If you really want to find
     the source of the Sixth Patriarch’s
          fountain
don’t look for it
     on the one bank or the other
          or in the middle of the stream

Translation W. S. Merwin