There are statues in Buddhist temples, and people pray in front of them. These are the center of faith. Usually, there are many Buddha statues in a temple. One of them is designated as the principal statue (本尊).
However, sometimes the principal statue is placed inside a closed door and cannot be seen. These are called the secret statues (秘仏).
Many of the temples with secret statues belong to the Shingon sect （真言宗） and the Tendai sect （天台宗）. There is a theory that these sects are related to ancient Japanese Shinto (shrines：神社). The essence of the faith in shrines （御神体） is usually placed in the main shrine building in an invisible manner.
Some secret statues are opened once or several times every year, and other can be seen once every 33 years. Zenkoji Temple （善光寺） in Nagano City is an absolutely secret statue and has not been opened for nearly 1000 years. In many cases, a substitute statue is placed in front of them, and visitors worship it.
