Nichiren summarizes Lotus Sutra Buddhism faith and practice

"Next, the teaching of the “Life Span” chapter is what I, Nichiren, personally depend on. Although T’ien-t’ai and Dengyō also understood it in a general way, they never put it into words or proclaimed it. The same is true of Nāgārjuna and Vasubandhu. The verse section of the chapter states, “... single-mindedly desiring to see the Buddha, not hesitating even if it costs them their lives.” As a result of this passage, I have revealed the Buddhahood in my own life. The reason is that it is this sutra passage that has enabled me to embody the Three Great Secret Laws, or the reality of three thousand realms in a single moment of life, that is found in the “Life Span” chapter. But keep this secret, keep it secret. 

The Great Teacher of Mount Hiei [Dengyō] journeyed to China and received instruction on the point of this passage. “Single” of “single-mindedly” means the one pure way, and “mind” means all phenomena. That is why the Great Teacher T’ien-t’ai, explaining the Chinese character for “mind,” said that its four brush strokes represent the moon and three stars, and that this implies that the mind of the effect [of Buddhahood] is pure and clean. I, Nichiren, say that “single” stands for myō, or mystic, “mind” for hō, or law, “desiring” for ren, or lotus, “see” for ge, or flower, and “Buddha” for kyō, or sutra. In propagating these five characters, practitioners should “not hesitate even if it costs them their lives.”

“Single-mindedly desiring to see the Buddha” may be read as follows: single-mindedly observing the Buddha, concentrating one’s mind on seeing the Buddha, and when looking at one’s own mind, perceiving that it is the Buddha. Having attained the fruit of Buddhahood, the eternally inherent three bodies, I may surpass even T’ien-t’ai and Dengyō, and excel even Nāgārjuna and Mahākāshyapa. The Buddha wrote that one should become the master of one’s mind rather than let one’s mind master oneself. This is what I mean when I emphatically urge you to give up even your body, and never begrudge even your life for the sake of the Lotus Sutra. Namu-myoho-renge-kyo, Namu-myoho-renge-kyo. -- Nichiren