When you visit Daigo-ji in Kyoto, you get two--or even three--temples for the effort of one. Find out what I'm talking about in this episode of--
TEMPLE TALES!
Temple Number 11 of the Saigoku 33 Kannon Pilgrimage Route in Japan is named "Kami Daigo-ji." The kami is important, as it signifies that this is "Upper" Daigo-ji. Daigo itself means "ghee," the clarified butter used in Indian cuisine. In Chinese usage it's refined cream cheese, but both cultures use it metaphorically to signify the "crème de la crème," which in a Buddhist context is nirvana, the dharma (the Buddha's teaching), or Buddha nature.
Red leaves before the Two Kings Gate at Shimo Daigo-ji
If I understand this correctly, the idea is related to the greatest work by the Shingon founder, Kobo Daishi (also called Kukai), titled The Ten Stages of the Development of Mind, written in 830, as well as its simplified summary, The Precious Key to the Secret Treasury. In these Kukai set out (natch) ten stages: the first three are increasingly-aware levels of the "natural man"; four and five are Southern Buddhist teachings (the Shravakayana and the Pratyekabuddhayana of Theravada; see Episode 028.) The next five are all schools of Mahayana Buddhism, in ascending order of acceptability (to Kukai): the Hosso (Consciousness-only), Sanron (Three Treatise), Tendai (Tiantai), Kegon (Avatamsaka), and, at the top, the Shingon (True word, or Mantra) School.
Thus, the "crème de la crème," the Daigo, is in fact the Shingon School.