The Descent of Maitreya

One day, Zen Master Daoying brought up a koan with Zen Master Dongshan—Nanquan testing a monk. Nanquan (Puyuan) asked the monk: "What sutra are you expounding?" The monk said: "The Sutra of Maitreya's Descent." Nanquan said: "When will Maitreya descend?" The monk said: "He is presently in the heavenly palace, and will descend in the future." Nanquan said: "There is no Maitreya in the heavens above, and no Maitreya beneath the earth."

After recounting this, Daoying asked Dongshan: "There is no Maitreya in the heavens above, and no Maitreya beneath the earth—then who gave them those names?"

Dongshan was so shaken by the question that his meditation seat trembled. He said: "Master Ying, when I was at Yunyan, I once asked the old master a question that made the fire stove shake. But your question today leaves me drenched in sweat all over!"