Yakushi sanzon, Yakushi triad (薬師三尊)
Yakushi sanzon, or Yakushi triad, is one of the styles to place Buddhist images in Buddhism.
It is a triad style and consists of Yakushi-Nyorai (Bhaisajyaguru) at the center (Chuson) and two Kyoji (attendant figures), Nikko Bosatsu (Sunlight Bodhisattva) on the left and Gakko Bosatsu (Moonlight Bodhisattva) on the right. (The 'left' or 'right' in this case is the direction as seen from Yakushi-Nyorai).
The name of Gakko Bosatsu means to be free from the burning earthly desires of life and death of living things with the coolness of the moon.
The statue of the principal image of Buddha at Kondo (Golden Hall) in Yakushi-ji Temple in Nara City is an old example of Yakushi sanzon statues and is one of the masterpieces in Japan.
Generally, Chuson was made as a sedentary statue and Kyoji were made as standing statues like the statues of Yakushi-ji Temple, but in some cases both Chuson and Kyoji were made as sedentary statues such as in the Daikodo Lecture Hall of Horyu-ji Temple.
Nikko Bosatsu and Gakko Bosatsu
Nikko Bosatsu and Gakko Bosatsu are described as the main Buddha in the Buddhist paradise of Yakushi-Nyorai, the realm known as Joruri or Pure Lapis Lazuli in the eastern quarter, Vaiduryanirbhasa in Sanskrit in "Yakushi Hongan-kyo Sutra," and it can be said that there is neither faith nor statues of Nikko Bosatsu and Gakko Bosatsu individually, other than the statues of the Kyoji of Yakushi-Nyorai.
From the viewpoint of iconography, each Nikko and Gakko Bosatsu often has the sun disc and the moon disc, but there are old cases where they have no belongings, like the statue at the Kondo hall in Yakushi-ji Temple in Nara.
In addition, in some cases Nikko and Gakko Bosatsu are Kyoji in place of other statues except at Yakushi-Nyorai. For example, the Kyoji of Senju Kannon (Sahasrabhuja-arya-avalokites 'vara, "Thousand-armed Kannon" or Kannon with a thousand arms) Statue, the principal image of Buddha at Dojo-ji Temple in Wakayama Prefecture, are Nikko and Gakko Bosatsu.
The Nikko Bosatsu and Gakko Bosatsu statues which are placed on both sides of Fukukensaku Kannon, (or Fukukenjaku Kannon, Never Empty Lasso Kannon (deity of Mercy)), the principal image at Hokke-do (Sangatsudo) of Todai-ji Temple in Nara are famous as masterpieces of Tenpyo sculpture (style of sculpture created in Tenpyo period) but the original names of the statues are not known and they seem to have not been shaped as Nikko and Gakko Bosatsu from the beginning.