Known literally as the bodhisattvas of lunar and solar radiance, the bodhisattva Gakko and counterpart Nikko are the representatives of the bodhisattva realm presided over by Yakushi Nyorai (Bhaisajyaguru-vaiduryaprabharaja), the Buddha of Healing. They are most often represented as attendants to Yakushi. This triad enjoyed great popularity in Japan from as early as the 8th century, with representative examples housed in Nara's Todaiji and Horyuji Temples. Typically, the bodhisattva Gakko is shown holding a lunar disc in the palm of one hand or mounted on a lotus stem. Nikko holds a corresponding solar disc.