The Eternal Buddha

Chapter 16 of the Lotus Sutra, The Lifespan of the Eternal Buddha, elucidated that Shakamuni Buddha, the historical Buddha, who appeared in India stated: "My good sons, I became Buddha in the very far distant past and it has been countless, millions of nayutas of kalpas since I, in fact, attained Buddhahood. Thus, my lifetime is of infinite asamkhya kalpas, forever existing and immortal."
This Chapter also expounded that the Eternal Buddha's true form has been preaching the law beyond time and space for the salvation of mankind. This is an extremely significant point for the people born in the period of the last and decadent Dharma, the Mappo Period.
To some people the word, Buddha, makes reference to Amida Buddha, Yakushi Buddha, Dainichi Buddha, and provisional buddhas of the Eternal Buddha. They differ depending on one's image. But, the Lotus Sutra brought an end to this general confusion. The Lotus Sutra clarified that the Eternal Buddha is the original body and all other buddhas are manifestations of the Eternal Buddha. With this clarified, it became apparent that men should follow the true teachings of the Lotus Sutra.
In order for mankind to attain rewards of enlightenment, it is important to sow the seed of Buddhahood. The seed of Buddhahood is the seed that creates merits and virtues of Buddha enlightenment. The seeds of Yakushi Buddha or those of Amida Buddha are not true seeds for Buddhahood because those buddhas are only manifestations of the Eternal Buddha. In other words, they are provisional buddhas and not buddhas that possess the root of eternal life. To summarize, by relying on the primordial eight chapters of the Lotus Sutra (Chapters 15 to 22 in which Shakamuni Buddha revealed that he was the original Eternal Buddha in the primordial land) one could receive the true seed of Buddhahood.
Nichiren Shonin, who appeared in this Mappo Period, preached faithfully the teachings of the primordial eight chapters of the Lotus Sutras that ordinary people could receive the seed of merits and virtues of Buddhahood by repeated chanting of the Odaimoku, NamuMyohoRengeKyo.
As mentioned above, the Lotus Sutra is the only sutra which gives a chance to everyone to attain Buddhahood
In addition, the Lotus Sutra expounds a path for people of inferior capabilities and common people in the Mappo Period, Also, it elucidated the message of the Eternal Buddha as the true guide. Therefore, the Lotus Sutra transcends all other sutras. Based on such integrated teachings it has continued to be revered by many people from ancient times.