Okunoin is the largest cemetery in Japan. Mt. Kōya is primarily known as the world headquarters of the Kōyasan Shingon sect of Japanese Buddhism.
Shingon Buddhism (真言宗 Shingon-shū) is one of the mainstream major schools of Japanese Buddhism and one of the few surviving Esoteric Buddhist lineages that started in the 3rd to 4th century CE that originally spread from India to China through traveling monks.
Today, there are very few books on Shingon in the West and until the 1940s, not a single book on Shingon had ever been published anywhere in the world, not even in Japan. Since this lineage was brought over to Japan from Tang Dynasty China over 1,100 years ago, its doctrines have always been closely guarded secrets, passed down orally through an initiatic chain and never written down.
Music by Krzysztof Komeda (Rosemary's baby soundtrack)