"Let me see if I can paraphrase one of Nichikan’s arguments that show Nichiren to be the True Buddha:
In the lifespan chapter of the Lotus Sutra, we find that Shakyamuni did not actually attain Enlightenment for the first time in India. The time period of his Enlightenment is the Remote Past of Gohyaku Jintengo. This was a long time ago, but it is still a finite time period. Therefore, Shakyamuni’s Enlightenment is not Eternal. His Buddhism is obviously only a provisional teaching. There can be no doubt about this.
In the “Mystic Principle of the True Cause,” Nichiren Daishonin elucidates that Shakyamuni’s teacher in the Remote Past was actually an older Buddha, the Original Buddha of Kuon Ganjo. This is the Buddha of Musa Sanjin; or the Buddha who is naturally or intrinsically endowed with the Three Bodies. In the Kaimoku Sho, Nichiren Daishonin clearly reveals that this Buddha from the really infinite past is none other than the Daishonin Himself. He appears in the Latter Day to reveal True Buddhism exactly as predicted by Shakyamuni.
As some of you know, Soka Gakkai has finally pretty much admitted that the “Mystic Principle of the True Cause” or Hon’in Myo Sho is a rather lame forgery — more on that later. As far as I know, that Gosho was the only source for the term kuon ganjo. So it seems like we could move past this old discussion of remote versus remoter, even more remote, and remotest past.
Nichiren Shonin apparently referred to the Shakyamuni who awoke in the Remote Past as the Buddha of Musa Sanjin. It seems to me this is obviously no particular person, since all three bodies are uncreated and eternally existent. However, in recorded history, Shakyamuni was still the temporal identity of the Buddha of Musa Sanjin. At any rate, gohyaku-jintengo, understood this way already covers eternity, or time without beginning or end.
IIRC, the other Nichiren Schools also take gohyaku-jintengo or ‘Remote Past’ to already be a symbol for deathlessness, eternity, or time without beginning. There is no need for Kuon Ganjo, a term which does not appear at all in the Lotus Sutra or Nichiren’s authentic writing.
It will be difficult, but I hope Soka Gakkai scholars can put this line of reasoning — “The inconceivably long period of Shakyamuni’s original enlightenment as described in the Lotus Sutra is known as gohyaku-jintengo — but this is still a finite time.” to bed. We need to forget about it, and move on.