Nichiren Shōnin regarded the teaching of Ichinen Sanzen (One thought contains three thousand worlds) as a primary doctrine for people to approach enlightenment. As I have explained before, one thought that we think momentarily contains three thousand worlds. For example, a peaceful condition includes sorrowfulness, a silly condition is included in a truth, and even an evil thought is included in a truth as well. Therefore, since olden times, practitioners practiced enlightenment with silent practices, such as meditation to observe the truth calmly. This is called the “Theory of Ichinen Sanzen.”

On the other hand, Nichiren Shōnin said this world is Buddha’s territory of salvation. We should depend on the Buddha, rather than training hard and long by ourselves. So believing sincerely is the most important factor to progress towards enlightenment. By believing in the Buddha, we can receive the Buddha’s merits naturally and attain enlightenment. Nichiren Shōnin emphasizes actual faith rather than theoretical faith. It is called, “Actuality of Ichinen Sanzen.” Nichiren Shōnin said, “For those who are incapable of understanding the truth of the 3000 existences contained in one thought, Lord Śākyamuni Buddha, with His great compassion, wraps this jewel with the five characters of Myō, Ho, Ren Ge, and Kyō and hangs it around the neck of the ignorant in the Latter Age of the Decadent Dharma.” Although we do not know about the primary doctrine of Ichinen Sanzen, it is included in the five characters. When we “Juji” (uphold) the five words, the merits which the Buddha accumulated before and after His attainment of Buddhahood are naturally transferred to us. Believing and practicing the Lotus Sutra with all your heart is called Juji (Upholding). The core of Juji is just that, upholding the Odaimoku.