Solar Radiance and Lunar Radiance.
1 Sk: Suryavairocana and Candravairocana. Two bodhisattvas *bosatsu 菩薩 serving as leaders of the bodhisattva assembly in the realm presided over by *Yakushi 薬師; they are usually represented as the attendants of Yakushi, together with whom they form the Yakushi triad Yakushi sanzon 薬師三尊, with Nikkō to the left and Gakkō to the right. Their iconographical features are not fixed, but they often hold a solar disc (red) and a lunar disc (white) respectively, either in the palm of the hand or on a lotus, the stem of which is held in the hand: Nikkō is also associated with a three-legged bird and Gakkō with a hare or frog. Usually shown standing, they may be fully robed or bare down to the waist (e.g., those in Yakushiji Kondō 薬師寺金堂, Nara), and there are also instances in which they wear armor underneath their robes. Because of the great popularity of the Yakushi cult in Japan, there are many examples of images of these two bodhisattvas forming part of the Yakushi triad, but there are also instances in which they form a triad with other deities, such as Senju Kannon 千手観音, at Dōjōji 道成寺 in Wakayama Prefecture and *Fukūkenjaku Kannon 不空羂索観音, at Tōdaiji *Hokkedō 東大寺法華堂 (also known as Sangatsudō 三月堂).
2 Sk: Suryaprabha and Candraprabha. Two bodhisattvas found in Esoteric Buddhism mikkyō 密教. Nikkō appears in the Jogaishōin 除蓋障院 section of the Matrix mandala *Taizōkai mandara 胎蔵界曼荼羅, and is also identified with Kongōkō 金剛光 (Sk: Vajrateja) among the 16 Great Bodhisattvas jūroku daibosatsu 十六大菩薩 of the Diamond World mandala *Kongōkai mandara 金剛界曼荼羅, while Gakkō appears in the Monjuin 文殊院 section of the Taizōkai mandara and is included among the 16 Deities of the Auspicious Aeon gengō jūrokuson 賢劫十六尊 in the Kongōkai mandara.