Trees at entrance to Muryokou-in temple, trimmed in cloud shapes, Koya-san, Wakayama Prefecture, near Osaka, Japan. Mount Koya (Koyasan) is the center of Shingon Buddhism, an important Buddhist sect which was introduced to Japan in 805 by Kobo Daishi (also known as Kukai), one of Japan's most significant religious figures. A small, secluded temple town has developed around the sect's headquarters that Kobo Daishi built on Koyasan's wooded mountaintop