Historical clue formulations

• Riddle in Zen Buddhism — 2026-06-28
• Zen riddle — 2025-10-24
• Riddle in Zen Buddhism — 2019-10-26
• Zen master's query — 2017-03-26
• Paradox to be meditated on — 2014-04-27
• "What is the sound of one hand clapping?," say — 2010-02-14
• Zen question — 2006-04-20
• Zen master's question — 2002-03-29
• Zen riddle — 2001-03-21