He is the sambhoga-kaya Buddha who had thought about the relief of living things for a very long time (contemplation of five kalpas) and became Buddha by finding a way to achieve birth in the pure land.
非常に長期間衆生の救済の思索をめぐらし（五劫思惟（ごこうしゆい））、浄土への往生の手立てを見出したことにより仏となった報身仏。