Soaring 536 metres high, Mt. Yasumandake, Hirado’s highest mountain peak, is revered as a god by people in the local area. Since the mountain faces the ocean, it served as a way post for seafarers since ancient times, and was also worshipped to bring safety to maritime routes.

The great ocean road opened up between China and Japan in the 9th century by the Japanese missions to Tang China brought the teachings of esoteric Buddhism and Zen sects to Japan. Hirado island, located along this road, witnessed esoteric Buddhist temples erected on the slopes of Mt. Yasumandake and Mt. Shijiki; these places became sacred places for Shinbutsu-shūgō (the syncretised practice of worshipping Buddhist and Shintō deities in the same complex). On Yasumandake, the Saizen temple (Saizenji) and the Hakusanhime shrine (Hakusanhimejinja) were built. In the latter’s recesses stands a curiously-shaped stone pagoda from China that is known as a satsuma pagoda.

In the 16th century, the Portuguese Jesuits joined in the intermingling taking place on the ocean passage between Japan and China. The faith they propagated took root on the islands of Ikitsuki and Taku (Takushima), as well as on the western coast of Hirado. Christianity met fierce opposition from the Buddhist powers on Yasumandake, however. In the Edo period (1600-1868), the feudal lords of the Hirado domain solidified the ban on Christianity, which led Christians to conceal their faith and practise it with the trappings of Buddhism and Shintō. Owing to this, religious esteem for Mt. Yasumandake saw a revival, and there was a boom in pilgrimages to the recesses of Hakusanhime shrine. These recesses were referred to by the Hidden Christians as yasumandake no okunoin-sama (lit. “Mt. Yasumandake’s inner sanctuary”).