Zen masters throughout history, in countries like China and Vietnam, have encouraged reciting the Nembutsu as a Zen koan. A koan is a paradoxical question that’s contemplated on to encourage the realization of enlightenment.
In reciting the Nembutsu, which is Namo Amituofo in Chinese, the practitioner is told to ask himself who it is that’s doing the reciting. If, as Buddhism teaches, there is no “self,” then who is the one reciting the Nembutsu?
The answer to this question, which one is to realize the truth of in one’s own experience, is that it’s our own Buddha-nature, our True Self, calling forth our own Name, since our true nature is the same as Amida Buddha’s:
Koan after koan explores the theme of nonduality. Hakuin’s well-known koan, “Two hands clap and there is a sound, what is the sound of one hand?” is clearly about two and one. The koan asks, you know what duality is, now what is nonduality? In “What is your original face before your mother and father were born?” the phrase “father and mother” alludes to duality. This is obvious to someone versed in the Chinese tradition, where so much philosophical thought is presented in the imagery of paired opposites. The phrase “your original face” alludes to the original nonduality.