The connection between seals or mudra , divine protectors , dreams and Ûisang is told in a tale recorded in the Samguk yusa , in which Chih － yen dreams of a great tree growing in Korea that contains a mani pearl . This was taken to be a portent of Ûisang ' s arrival . Later , when Ûisang returned to Silla , supposedly to report the T ' ang emperor Kao － tsung ' s mobilisation of troops to attack Silla in 671 , the court ordered the head of the Sin ' in 神人 Sect , Myôngnang 明朗 , who had returned from China in 635 , to establish a platform to repel the Chinese with an esoteric mudra technique 文 頭 婁 秘 密 之 法 . The Sin ' in ritual was based on the Kuan － ting ching 灌頂 經 , a text of sigillation that protects from demons . In Silla , the tradition of the Sin ' in Buddhists seems to have overlapped with a stream of Hwaôm . Firstly , both claimed a lineage from Nâgârjuna , who in the Hua － yen tradition was acclaimed the discoverer of the Hua － yen ching from the palace of the dragon ( Nâga ) king 龍王 . He retrieved it after it had been lost for over 600 years . In the Esoteric tradition , Nâgârjuna obtained the Esoteric scriptures from an iron stupa where they had been kept hidden since the time of their initial preaching . The Sin ' in Sect similarly claimed a lineage from Nâgârjuna . Likewise , the Kuan － ting ching supposedly vanished from the face of the earth after three hundred years , but nine hundred years after the Buddha ' s decease , an ascetic monk rediscovered the text in a jewelled casket inside a cave .