Dainichi Nyorai is a Buddha in the context of Esoteric Buddhism, which includes practices that utilize mantras to attain enlightenment. The mantra chanted in veneration of Dainichi Nyorai is: "Oṃ vajra-dhātu vaṃ" ("金剛") and "Oṃ a vi ra hūṃ khāṃ" ("胎蔵"). In Esoteric Buddhism, Dainichi Nyorai represents the truth of the universe, and also is a reference to the universe itself. Dainichi Nyorai has two aspects, "金剛" and "胎蔵". "金剛" means diamond, and represents the wisdom necessary to attain enlightenment while "胎蔵" represents compassion. These two aspects are represented differently in the Dainchi Nyorai statues by the way its hands are posed. This statue in the picture represents the first aspect, "金剛". Fudo Myoo is an incarnation of Dainichi Nyorai, or the representation of Dainichi Nyorai's inner will.
The Kirikane (截金 or 切金) technique has been used for this statue. This tehcnique is a traditional Japanese decorative technique used for Buddhist statues. It uses gold leaf, silver leaf, or platinum leaf cut into lines, diamonds, and triangles, resulting in a both delicate and splendid appearance of the Buddhist statue.
This Buddha statue has small celestial beings in the aura. These beings are flying around the Buddha statue and celerating the Buddha. This type of aura is called hiten (飛天) and is typical amongst Buddhist sculptures.