Bhaiṣajyaguru, formally Bhaiṣajya-guru-vaiḍūrya-prabhā-rāja "King of Medicine Master and Lapis Lazuli Light"), is the buddha of healing and medicine in Mahāyāna Buddhism. Commonly referred to as the "Medicine Buddha", he is described as a doctor who cures dukkha (suffering) using the medicine of his teachings.
The name was rāja (King), but Xuanzang assumed it Tathāgata (Buddha). The translations and the commentary books of after ages obeyed the translation of Xuanzang. The figure of Bhaiṣajyaguru is expressed with a Tathāgata (Buddha) shape except for having a gallipot. Though it is also considered to be a guardian of the east, in that case, it is usually changed to Akshobhya. As an exceptional case, the Honzon of "Kōya-san Kongōbu-ji" was changed from Akshobhya to Bhaiṣajyaguru.
Bhaiṣajyaguru is described in the eponymous Bhaiṣajya-guru-vaiḍūrya-prabhā-rāja Sūtra, commonly called the Medicine Buddha Sutra, as a bodhisattva who made 12 great vows. On achieving Buddhahood, he became the Buddha of the eastern pure land of Vaiḍūryanirbhāsa "Pure Lapis Lazuli". There, he is attended to by two bodhisattvas symbolizing the light of the sun and the light of the moon respectively: