This is a teaching of esoteric medieval Tendai that is also found in the oral transmissions of the Nichiren Hokke Shu. From what I can gather, most schools understand this in the sense of “one person at a time.” The Taisekiji lineage takes it literally; the single person was Nikko and is now the Chief Abbot of Taisekiji.
In the early SGI I heard a similar idea of “A change on the destiny of a single person …” I took that “single person” to mean us, you and I, standing alone. It was only years later that I finally got it.
IIRC, it was around 1990 that President Ikeda said we needed a lot of President Ikedas to achieve Kosen Rufu. Many of us took this to mean that each of should stand up, take the initiative, and be the change we wanted to see. I think many of us did that. But I think we must have missed the point.
Going back to the early days, that Single Person was and still is Daisaku Ikeda and only Daisaku Ikeda. Many President Ikedas refers to Daisaku Ikeda multiplying himself through others. We are supposed to know his heart, and promote him and his views, not ourselves and our own shallow views.
We also hear the idea of the disciple exceeding the master. That also means Daisaku Ikeda exceeding Josei Toda. No one can ever surpass President Ikeda, he is the final master for all of eternity.
Don’t you agree!
Shout “Hai” in unison!