Ajikan (阿字観)
The term "Ajikan" refers to a method of meditation introduced by Kukai (a Buddhist priest) during the Heian period. It is also referred to as Ajikan Yoga, or Mikkyo (Esoteric Buddhism) Yoga.
Sitting with the back perfectly upright, breathing in a natural rhythmical way, practitioners meditate while watching the Bonji (Sanskrit characters) which is a manifestation of Dainichi Nyorai (Mahavairocana) in the Gachirin (a perfect round circle meant to represent the full moon, and the Buddha's knowledge and virtue which are considered perfect and all-encompassing) on a lotus flower painted on a hanging scroll. Originally, Ajikan was practiced by monks of the Shingon sect as a method to refine the mind, and was transmitted among the temples of the Shingon sect. Meditative practice methods include Susokukan (Breath counting meditation), Asokukan (Breathing meditation), and Gachirinkan (Moon Disc meditation).