The Sound of the One HandBy: Yoel Hoffman When The Sound of the One Hand came out in Japan in 1916 it caused a scandal. Zen was a secretive practice, its wisdom relayed from master to novice in strictest privacy. That a handbook existed recording not only the riddling koans that are central to Zen teaching but also detailing the answers to them seemed to mark Zen as rote, not revelatory. For all that, The Sound of the One Hand opens the door to Zen like no other book.