In Fire in the Lotus, Daniel Montgomery offers this explanation of the Daimoku. (He lists his source material inside parentheses.)

Just as the Dharma Flower is the quintessence of both universal truth and universal life, so its sacred title, Myoho Renge Kyo, is the quintessence of the sutra. All that remains is for us to identify ourselves with the Absolute. This is done by adding the first word, Namu, ‘I devote myself to’. The dharani which contains all dharanis, the mantra which contains all mantras, is Namu Myoho Renge Kyo.

Shakyamuni obtained enlightenment when he completely identified himself with the Absolute. We obtain enlightenment exactly the same way. Namu Myoho Renge Kyo is the enlightenment of the Buddha. Namu Myoho Renge Kyo is our own enlightenment, too. In Namu Myoho Renge Kyo we identify with the Buddha. In Namu Myoho Renge Kyo the Buddha identifies with us.

This identification is complete in every respect. Just as the Buddha is three bodies in one, so are we. ‘The person who chants Namu Myoho Renge Kyo is a Buddha. His body is the Dharma-body of the Buddha; his mind, the Reward-body of the Buddha; and his behavior, the Manifestation-body of the Buddha’ (Myoho-ama-gozen-gohenji, Showa-teihon, 1535).

The sects, Nichiren says, from the old Nara sects on down to the recent Kamakura sects, seek identity with only part of the threefold body of the Buddha. For example, to concentrate on the precepts taught by the historical Shakyamuni, as is done in the Little Vehicle is to worship only the Manifestation-body. To go to the other extreme worshipping only the eternal Principle (Dharma-body) as is done in esotericism, is to cut oneself off from the historical foundations. To worship only Amida is to concentrate on the Reward-body at the expense of the other two. The only correct object of worship is the three-in-one and one-in-three as expounded by Chih-i and Saicho. This is expressed in the Dharma Flower as the Eternal Buddha Shakyamuni.

‘All the sects except the Tendai Sect,’ he wrote in 1272, ‘worship wrong objects. The Kusha, Jojitsu, and Ritsu Sects (Hinayana) worship Buddha Shakyamuni, who is regarded as the person who eliminated illusions and attained enlightenment for the first time under the bodhi tree. They are as wrong as a crown prince who thinks that he is the son of a subject. The Kegon (Flower Garland), Shingon, Sanron, and Hoso (‘Consciousness-only’) Sects are Mahayana. The Hosso and Sanron Sects worship Buddha Shakyamuni as defined in the provisional Mahayana. They are as wrong as a crown prince who thinks he is the son of a colonel. The Kegon and Shingon Sects despise Buddha Shakyamuni and worship Buddha Vairocana (personifying the Absolute). They are as wrong as a crown prince who deserts his father and follows another king of unknown ancestry. The Pure Land Buddhists hold that Buddha Amitabha is their Buddha, and do not worship Buddha Shakyamuni. They do not know that Buddha Amitabha is one of the manifestations of Buddha Shakyamuni. The Zen Buddhists (who reject all traditions) are like a man of low birth who criticizes his parents when he gets some position in society. They despise the Buddhas and the sutras. All these sects worship wrong objects’ (Kaimoku-sho, 182-4, slightly altered).

Only in the Dharma Flower does Shakyamuni reveal the universal Buddha-seed, which permeates all life, and the fulfilment of that seed. It is the king of sutras just as the Original Buddha Shakyamuni, the fulfilment of the seed, is the origin of all Buddhas.

Next: Where Do Prayers Go?