East Asian Yogācāra School

We know that in Journey to the West, Chen Xuanzang (Tang Sanzagn or Tripitaka) is the reincarnation of the Golden Cicada (Gold Cicada or Jin Chanzi). So, did Guanyin Bodhisattva choose Chen Xuanzang or the Golden Cicada as the scripture seeker? And who ultimately achieves Buddhahood?