Hakuin Zenji (1689-1769) was one of the most important of all Japanese Zen masters. His commentary on the Heart Sutra is a Zen classic that reflects his dynamic teaching style, with its balance of scathing wit and poetic illumination of the text. Hakuin's sarcasm, irony, and invective are ultimately guided by a compassion that seeks to dislodge students' false assumptions and free them to realize the profound meaning of the Heart Sutra for themselves. The text is illustrated with Hakuin's own calligraphy and brush drawings.