Compare Hakuins "sound of a single hand," which is also a reference to Kanzeon. Ken Holmes, Chenrezik - Bodhisattva of Compassion: "The Suramgama Sutra tells how, in ages long gone by, the bodhisattva followed a certain Buddha Avalokitesvara, from whom he took his name, who instructed him to focus his meditation on the faculty of hearing. By analysing what at first seemed to be two things - external sound and the inner faculty of hearing - the bodhisattva soon recognised their inseparability; their non-duality. Neither could be found to have existence on its own and hence each was devoid of existence. By then pursuing this voidness, with direct awareness rather than intellectual analysis, the bodhisattva understood the whole question of consciousness and attained successive degrees of enlightenment, thereby acquiring extraordinary powers to help others. We find these powers, which are embodied in his mantra om mani padme hung, also mentioned in the Lotus Sutra. They enable him to manifest to anyone, in forms having direct relevance to their needs.
