This mantra is especially connected with the 4-armed Shadakshari method of Avalokiteśvara. The Dalai Lama is said to generally be an incarnation of Avalokiteshvara, and Hence the mantra is especially revered by his devotees. Chinese esoteric Buddhist exercise was dependant on deity yoga and also the "3 mysteries": mantra, mudra https://fashion61750.blogzet.com/mantra-an-overview-46000474