Gisan Zenkai (儀山 善来 1802–1878) was a Zen Master in 19th century Japan. He taught at Sōgen-ji 曹源寺 in Okayama. The most famous story about him concerns his conversation in 1837 with the disciple cooling his bath: this is given in an abbreviated version in Zen Flesh, Zen Bones, and in more expanded version in other sources (such as this). The Zen Flesh, Zen Bones version is:
- "A Zen master name Gisan asked a young student to bring him a pail of water to cool his bath.
- "The student brought the water and, after cooling the bath, threw on to the ground the little that was left over.
- "'You dunce!' the master scolded him. 'Why didn't you give the rest of the water to the plants? What right have you to waste even a drop of water in this temple?'
- The young student attained Zen in that instant. He changed his name to Tekisui Giboku (1822—1899), which means a drop of water."