The construction of the sculpture is from a single block of kaya wood (Japanese nutmeg yew, as researched by The Royal Botanic Gardens, Kew) which was split down a vertical plane into two main parts which were then partially hollowed out and then joined. This was done in order to relieve stresses occurring over the ages due to the wood drying out which have might led to untoward splitting of the sculpture. The line of this original fissure can be seen running down the sides of the head and through the upper part of the torso. Separate arms, and the sides of the trunk are joined with iron staples forming a hollow interior - a precursor of the later Kamakura period method of yosegi-zukuri in which the whole is composed of an outer shell formed of individually sculpted components.
Carbon dating (RCD-8116 and RCD-8162) indicates that the torso, head and shoulders date from the Heian period (10th century), while the lower part was made during the Kamakura period (12th-13th century).
The figure follows the classic Heian style with a gentle countenance, well-sculpted head coiffure, on the upper part a crystal nikkei symbolising enlightenment, and on the forehead a byakugo (Sanskrit Urna) through which the light of Buddhism is transmitted throughout the world. The hair of some Heian sculptures tends not to be formed in tight curls, but in rounded or truncated pyramidical form like this piece. The fall of the robes is indicative of early period Heian wood sculpture, with the folds over the right shoulder tucked under the robe falling from the left shoulder and across under the right side of the waist, and dropping down a few hand’s breadths to rise again over the right arm then falling away.
The figure might be compared with classic examples of the Tempyo era like the standing Yakushi Nyorai (164.8cm high) in the Kofukujin temple (registered as a National Treasure), and the standing Yakushi figure (169.7cm high) in the Jingoji temple, Kyoto, or the seated Miroku Bosatsu in the Todaiji Nara (39cm high) (registered as an Important Cultural Property).
This style of dress is found also on late Heian sculpture like the standing Amida Nyorai in the Jizoin temple, Kyoto (registered as an Important Cultural Property), but in general the robes of such later Heian period figures sweep across the body and under the right arm with no drapery falling from above so that the right side of the body is exposed.