As already stated, the Primal Vow (hongan) expresses Amida Buddha’s desire to save all sentient beings. The Daimuryoju-kyo (Larger Sutra on Immeasurable Life) lists 48 Vows that Amida Buddha made when he was Hozo Bosatsu. The 18th of these vows was traditionally considered the most important. The wording of this 18th Vow is:
If, when I attain Buddhahood, all sentient beings in the ten directions who recite my name even ten times with sincere mind, faith serene, and wish birth in my country are not born there, may I not attain the supreme and greatest Enlightenment. Only those who commit the five perversities are excluded.
Zendo Daishi considered this 18th Vow to be the core of the 48 vows. The original wording of that part of the vow translated above as “recite my name even ten times,” is naishi janen, which literally translates to “up to ten thoughts.” It was Zendo Daishi who interpreted this to be “ten recitations,” and that is why the 18th Vow is translated in Jodo-Shinshu as it is. Zendo Daishiemphasized birth in the Pure Land through reciting the name of Amida Buddha, Namo Amida Butsu, which is referred to as the “Nembutsu.”
Master Honen accepted this teaching and referred to the 18th Vow as the “King of Vows.” He delved deeply into the thought of “birth in the Pure Land through recitation of the Nembutsu,” which is central to the 18th Vow, and emphasized the “Exclusive Practice of (Reciting) the Nembutsu” (senju nembutsu), in which no practice other than reciting the Nembutsu is necessary.
The Venerable Master accepted this teaching of completely denying the “Path of Sages” and “various practices,” and made the Nembutsu his exclusive practice. As described in Part One, however, the monks and scholars of the then established schools of Buddha-dharma who considered “self-centered effort” in performing “various practices” to be what following the Buddhist path meant, did not accept that teaching.