To begin Buddhist chanting in the Nichiren Shoshu tradition, you start with Daimoku Sansho. The word Daimoku means the supreme invocation or Nam-Myoho-Renge-Kyo. This expression also indicates the chanting of Nam-Myoho-Renge-Kyo. The word Sansho means three. Daimoku Sansho means to face the Gohonzon (object of worship) and chant Nam-Myoho-Renge-Kyo three times (in a specific way like our Chief Priest demonstrates), bowing in reverence to the Three Treasures of True Buddhism.
Nichiren Daishonin states in "On Attaining Buddhahood in this Lifetime" ("Issho jobutsu-sho"),
Let's deepen our faith in the Dai-Gohonzon, strengthen our daily practice, and advance forward in our Shakubuku efforts - in order to achieve the peace and security of the land.While deluded, one is called a common mortal, but once enlightened, he is called a Buddha. Even a tarnished mirror will shine like a jewel if it is polished. A mind which presently is clouded by illusions originating from the innate darkness of life is like a tarnished mirror, but once it is polished it will become clear, reflecting the enlightenment of immutable truth. Arouse deep faith and polish your mirror night and day. How should you polish it? Only by chanting Nam-Myoho-Renge-Kyo.
(Gosho, p. 46)