Kobo Daishi lived in the Heian Period (794-1185). Before his death, he was known as Kūkai. Among other professions including scholar, artist etc., he was a priest and was the founder of the Shingon (literally translated to "true word") School of Japanese Buddhism.
This statue is "眼入", meaning that it has glass eyes painted with pupils inserted. The insertion of transparent eyes into Buddhist statues is a uniquely Japanese technique. One remarkable point of this technique is that when you look at this statue, your eyes will still match the eyes of the Buddha from any angle. Many people believe that this helps you appreciate the connection you have with the Buddha.
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.