Honen, in twelfth-century Japan, made the decisive move: he taught that the recitation alone is the practice appropriate to the age, and that other disciplines may be set aside. This was radical enough to get him exiled and his movement suppressed.
Shinran, his disciple, went further in a direction that is worth following carefully. If the practitioner recites in order to secure rebirth, then the recitation is a calculated act and self-power has re-entered by the back door. Shinran concluded that even the entrusting mind is given by Amitabha, not generated by the practitioner; that a single moment of genuine trust settles the matter; and that subsequent recitation is therefore gratitude rather than technique. He drew the further conclusion that the person who knows themselves incapable is better placed than the person confident of their own virtue, stated in the celebrated line that if even a good person attains birth, how much more so an evil one. Shinran married, ate meat, refused the title of teacher, and founded what became Jodo Shinshu, the largest Buddhist denomination in Japan.
The parallel with Protestant justification by faith is close, and it is not manufactured by Western observers: Japanese and European writers noticed it independently, and sixteenth-century Jesuits in Japan found the resemblance unsettling. Both traditions distinguish reliance on one's own works from reliance on another's completed act, both treat trust as itself a gift, and both had to answer the charge that if works do not matter, conduct is free. Shinran addressed that objection in the same terms Paul did, and rejected the licence.
The differences are equally real. Amitabha is not a creator, has no claim on obedience, and does not judge; the Pure Land is a stage toward awakening rather than a destination; and the analysis of the human predicament remains the Buddhist one, ignorance and craving, rather than sin against a personal God.