The Logic of the True Nature of the Gohonzon
First, a definition(defined by the Lotus Sutra and Nichiren Daishonin):
Gohonzon = Person + Law(Namu Myoho renge kyo)
Are we agreed? If yes, continue.
Second, another definition(defined by the Lotus Sutra and Nichiren Daishonin)
Buddha = Person + Law
Are we agreed? If yes, continue
Therefore:
Buddha = Gohonzon = Person + Law
Are we agreed? If yes, continue
Third, a definition(defined by the Lotus Sutra and Nichiren Dashonin)
Buddha = Eternal Shakyamuni Buddha or Shakyamuni of the Juryo Chapter
Are we agreed? If yes, continue. If not, I can do one of two things: I can cite the passages in the Lotus Sutra and Gosho that He is the preminant Buddha or I can cite two reasons. I prefer to cite the two reasons: 1. This Buddha was the first to realize the Law; This Buddha was the first to teach the Law and therefore, all other Buddhas including you and I(now or in the future) attain to Buddhahood through the Law of this Buddha.
Are we agreed? If yes. continue
Gohonzon = Eternal Buddha Shakyamuni
What is the worth in knowing this. Ten million SGI members chant to the Gohonzon and gain many benefits without knowing this?
The mercy and the compassion of the Buddha is such that chanting Namu Myoho renge without wisdom is a tremendous source of benefit. However, without correct faith, no one will ever develop the true wisdom of the Law, the wisdom and the merits accumulated will quickly evaporate. That is why Nichiren Daishonin teaches in the Kaimoku Sho:
"... Sakyamuni Buddha is the supreme leader and excellent eyes for all the people. He is the bridge that enables them to cross the river of evil passions; he is the skipper who guides them over the sea of life and death; and he is the fertile field in which they plant the seed of merits. ...' The meaning of these words in the Lotus Sutra is shiningly clear -- brighter than the sun in the blue sky and the full moon at midnight. Look up and put your faith in it. Prostrate yourself before it and think hard about it."
Without eventually acknowledging Shakyamuni Buddha of the Juryo-hon Chapter, we will lose our way over the sea of life and death. If we turn against this Buddha, we will certainly never make it to the other shore.