Kongōbu-ji is the head temple of Kōyasan Shingon Buddhism, located on the serene Mount Kōya in Wakayama Prefecture, Japan. This temple, meaning "Temple of the Diamond Mountain Peak," is part of the "Sacred Sites and Pilgrimage Routes in the Kii Mountain Range," recognized as a UNESCO World Heritage Site. Founded in 816 by the monk Kūkai, Kongōbu-ji is not only a place of deep spiritual significance but also a treasure trove of cultural heritage, featuring Japan's largest rock garden and a wealth of National Treasures and Important Cultural Properties.