Honored Questioner
You ask about the Treasure Tower and about Abutsu-bō. I will explain it as I understand it from the writings myself.
The Treasure Tower comes from chapter eleven of the Lotus Sutra. There, an enormous tower rises out of the earth, adorned with seven treasures, and remains suspended in the air. Inside sits Many Treasures Buddha, bearing witness that the Lotus Sutra is true. This may sound like a story far removed from your own life. But Nichiren Daishonin explains that this tower is nothing outside of you. It is the direct form of your own Buddha nature, the seed of enlightenment that lives in every ordinary person.
Think of a closed door in a dark room. As long as the door stays shut, you see nothing of what lies behind it. That closed door is your own confusion and doubt, what the writings call mumyō, fundamental darkness. When you recite Namu-myoho-renge-kyo with faith, that door opens. What becomes visible is not something new arriving from outside. It is what was already present in you the whole time.
Nichiren Daishonin wrote this to Abutsu-bō, a man of seventy living in exile on the island of Sado. Abutsu-bō had first followed another school, the Nembutsu. When he became convinced by the Daishonin's teaching, he and his wife Sennichi-ni secretly brought food and supplies to the Daishonin at night, despite a ban from the local authorities. He risked his own life for this devotion.
To this man, the Daishonin writes the following, and I give you the words exactly as they stand:
"Abutsu-bō is himself the Treasure Tower, and the Treasure Tower is Abutsu-bō himself."
And further, in the same spirit:
"In the Latter Day of the Law, there is no other Treasure Tower than the figures of the men and women who embrace the Lotus Sutra. It follows that, therefore, whether eminent or humble, high or low, those who chant Namu-myoho-renge-kyo are themselves the Treasure Tower, and they are also Many Treasures Buddha himself."
This is not a nice phrase meant to comfort. It is a direct statement about what an ordinary person is. Abutsu-bō was no priest, no scholar, no man of standing in the eyes of the world. He was old, exiled, and carried food through the cold at night. That exact body, that ordinary, mortal body, is what the Daishonin calls the Treasure Tower.
This connects to what is called sokushin-jōbutsu, attaining Buddhahood in this very body. Before the Lotus Sutra, other schools taught that a person first had to cast off earthly desires, over many lifetimes, before reaching enlightenment. The Lotus Sutra says something different. Your body as it is now, with all its ordinariness and flaws, is already the form in which the Law shows itself. The writings therefore call the body "the palace of the ninth consciousness, the unchanging reality that governs all functions of life."
On the Gohonzon, the central inscription Namu-myoho-renge-kyo-Nichiren is that same Treasure Tower, now made visible as an object of faith. When you sit before it and recite, that is not an act directed toward something outside you. It is the opening of the door that you yourself are.
深く感謝いたします
Namu Myoho Renge Kyo
You are asking if you need a Gohonzon before you can chant Namu Myoho Renge Kyo. Nichiren Daishonin first taught Namu Myoho Renge Kyo in 1253, at a temple called Seicho-ji, on Mount Kiyosumi. He did not write the first Gohonzon until 1273, twenty years later, while living in exile on Sado Island. For twenty years, people chanted this Law without a scroll to look at. The object came after the practice, not before it.
In 1273, from that exile, Nichiren wrote a letter to a baby girl named Kyo-o. He told her, "I, Nichiren, have inscribed my life in sumi ink, so believe in the Gohonzon with your whole heart." Sumi ink is a black ink you make yourself, by grinding a hard stick against a wet stone until the water turns dark. When he wrote her Gohonzon, he put everything he had realized through years of hardship into that ink itself.
Four years later, in 1277, he wrote something that sounds like the opposite. He told a woman named Nichinyo, "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."
Here is the picture that holds both of these together. Think of a mirror on a wall in a dark room. Your face already sits on your head, mirror or no mirror. What the mirror gives you is the sight of it, clearly, for the first time. The Gohonzon works the same way. Nichiren's life is folded into the ink, the way silver is folded into the glass of a mirror, and what that mirror finally shows you was always your own face.
Your Buddha nature, the part of your life capable of Buddhahood, is already inside you, the same way your face is already on your head before you ever look in a mirror. Chanting Namu Myoho Renge Kyo is what starts to make that visible, to yourself and to your life around you.
Nichiren describes what actually happens when you chant with a picture worth holding onto. He compares it to a bird singing inside a cage. When the caged bird sings, birds flying free outside hear it and gather close. And when those birds gather close, the bird inside the cage pushes harder to get out. He wrote, "When with our mouths we chant the Mystic Law, our Buddha nature, being summoned, will invariably emerge." Your voice is the caged bird singing. Chanting calls your own Buddha nature forward from inside you, and in the same movement, it calls something from outside you as well. To his disciple Shijo Kingo, Nichiren wrote, "Buddhism teaches that, when the Buddha nature manifests itself from within, it will receive protection from without. This is one of its fundamental principles." Inside and outside move together, calling each other at the same moment.
Now the question underneath your question: what if you do not fully understand any of this yet? What if your faith feels small, or shaky, or you are not even sure you believe it?
Nichiren answered this with a story he told to a woman he called the lay nun Ueno. In China, a famous calligrapher named Wu-lung hated Buddhism so much that on his deathbed he made his son promise to never once copy the Lotus Sutra. His son, I-lung, kept that promise for years, until a king ordered him to write out just the sutra's title. I-lung obeyed the king, against his own father's wish, without believing a single word of what he wrote. Three days later, at his father's grave, his father appeared to him, freed from suffering, and said, "Your hand is my hand. Your body is my body. The characters you wrote were characters written by me. You did not believe in the Lotus Sutra, but you saved me by writing the title. Faith in the Lotus Sutra is the same. You can have faith without realizing it and still be saved."
This story matters because you can begin without arriving already certain, already understanding everything, already glowing with faith. I-lung did not believe a word of what his own hand wrote, and it still reached his father. Your own voice, and enough honesty to use it tonight, is what this practice actually asks of you.
Go deeper: Gongyo: The Eternal Law
あなたの真摯な問いに、心より感謝申し上げます。
Namu Myoho Renge Kyo
