Ungen-coloring is a coloring technique introduced from China to our country in the 7th century. It is mainly used for something Buddhist, and expresses "vivid colorfulness" and "three-dimensional effects". In Ungen-coloring, there are some differences between China and Japan in spite of being the same painting material and same drawing method. Chinese Ungen-coloring represented by Mogao Caves in Dunhuang is "three-dimensional effects". On the other hand it emphasizes "vivid colorfulness" in Japan. As a result, it is thought that Japanese Ungen-coloring is two-dimensional and then decorative.

　In this paper, I investigated the reason why the coloring technique, which was originally a coloring technique representing three-dimensional effects, became two-dimensional and later decorative in Japan. Until the Nara period, it was coloring with three-dimensional effects, but gradually changed into Japan's own original Ungen-coloring. There is the influence of two-dimensional painting (Buddhist picture) at that time, and the time of the change is thought to be related to the introduction of esoteric Buddhism into Japan.

　In the 8th century, the Ungen-coloring which had three three-dimensional effects became two-dimensional in the 10th century after the transition period of the 9th century. And in the 11th century Byodoin phoenix hall, it seems that the influence of the aestheticism of the Heian aristocracy has shifted to the Ungen-coloring that emphasizes decorativeness. It is the Byodoin phoenix hall that is showing the "vivid colorfulness" more than anywhere in Japanese Ungen-coloring.

　This paper presents the results of a study on changes in memory for object color. In ex1, we presented object images painted with the color near the boundary between the two categories to participants. Objects in 2 conditions have a typical color known in general, and objects in another condition have low color typicality. The result found that color memory may change in the direction towards the typical color of each object with high color typicality when two object images of the same color are presented. On the other hand, no significant differences found for objects with atypical colors. In ex2, the participants were required to classify a set of color patches into several color categories. The patches were composed of the same colors used in ex1. When the color categories classified by the patch were different from the typical colors of the objects, color memory changed more in the direction of the typical color than that of the focal color of the category. These results suggest that knowledge about typical colors of objects may affect color recognition and memory.