In the practice of Shingon Buddhism, developed by its Japanese founder Kukai (Kobo Daishi) in the early ninth century, one slowly awakens to the realization that one is not separate from anything in either the phenomenal or non-phenomenal universes. The means of achieving this realization are available to the practitioner, who is generally referred to as a priest, in the form of several thousand highly structured individual practices. Shingon, which means “true word” or “mantra,” uses practices involving hundreds of mantras, mudras and visualizations at deepening levels that are revealed as one’s practice matures. At the heart of all of these is the notion of Honzon Kaji, becoming one with the main deity.
Honzon simply refers to the main deity in any given ritual. Kaji refers to the enhancement of a sentient being’s power through the Buddha’s power (Nyorai-kaji-riki), and it translates the Sanskrit word adhisthana. Sanskrit terms like this came to Japan inscribed in the Siddham, or Brahmini, script, the form of written Sanskrit that was used by priests in India in the fourth to eighth centuries and then later in China and Japan. Understanding the meaning of Siddham syllables was one of the beginning steps taken by Kukai to understand the esoteric teachings in China.