The Emperor Go-Kameyama believed his palace was haunted, so he called upon various priests to exorcise the ghosts. None, however, were successful. His advisors suggested he seek the assistance of the Zen Master, Mukan Fumon. Called to the court, Fumon told the Emperor, “The honored Confucius wrote that demons and ghosts are helpless before men of virtue. My monks and I can dispose of them without difficulty.” Then Fumon and several of his disciples took up residence in the palace. Unlike the earlier priests who had tried to rid the palace of its unwanted occupants by magic rites and religious ceremonies, Fumon did not perform any particular rituals; he did not even chant the sutras, as was common for Buddhists. He and his monks simply sat quietly and persistently in zazen. The ghosts did not disturb them. The Emperor was so impressed that he declared the palace a Zen monastery and appointed Fumon its abbot.
[Mukan Fumon – Zen Masters of Japan: 82-83]