On Sado Island, in the cold spring of 1273, Nichiren Daishonin sat down and inscribed a mandala in sumi ink for a young follower named Kyo'o. He did not send a statue. He did not send a painted face. He sent columns of characters, names without bodies, and one instruction folded inside them: "I, Nichiren, have inscribed my life in sumi ink, so believe in the Gohonzon with your whole heart."
That choice was not an accident of materials. A carved face fixes a figure to one century, one expression, one set of features. Ink carries a name without carrying any of that. Nichiren stripped away everything that could let a follower say that is not what a Buddha looks like, because what he inscribed was never meant to resemble anything outside the person holding it.

From that same exile Nichiren wrote a line still copied onto altars today: "Never seek this Gohonzon outside yourself. The Gohonzon exists only within the mortal flesh of us ordinary people who embrace the Lotus Sutra and chant Namu-myoho-renge-kyo. The body is the palace of the ninth consciousness, the unchanging reality that reigns over all of life's functions."
Read that twice. He is not describing a scroll. He is describing where the scroll's power actually lives.
The mechanism follows a year later in Kanjin no Honzon-shō, also written on Sado. A mind cannot see its own shape without something to look into. Nichiren named the problem and answered it in the same breath: "A mind now clouded by the illusions of the innate darkness of life is like a tarnished mirror, but when polished, it is sure to become like a clear mirror, reflecting the essential nature of phenomena and the true aspect of reality. Arouse deep faith, and diligently polish your mirror day and night. How should you polish it? Only by chanting Namu-myoho-renge-kyo."
A tarnished mirror. A clear one. Chanting is the polishing. No third option is offered, and no one else stands ready to do the polishing on your behalf.

A person who sits before an altar every morning for years is not repeating a habit for its own sake. Each session is a return to the same mirror, checked again, polished again. Some mornings the glass comes back clear. Other mornings it does not. Nichiren never promised the second kind would stop happening. He promised the polishing itself was the whole of the practice.
This is why 依正不二 (esho funi, "the oneness of life and its environment") sits at the center of this teaching. Life shapes environment the way a body casts its shadow. A cluttered altar and a cluttered week are one condition, seen from two angles.

Three schools that trace themselves back to this same island read the mandala three different ways: object of devotion, object of worship, representation of the eternal Buddha. Let that disagreement stand as it is. Underneath all three readings sits the same letter, written by the same man, to the same handful of frightened followers, carrying the same instruction. NEVER SEEK THIS OUTSIDE YOURSELF.
Sit before your Gohonzon tonight. Notice which mirror is looking back.
鏡は自分自身
Namu Myoho Renge Kyo