Nam-myoho-renge-kyo

The essence of Buddhism is the conviction that we have within us at each moment the ability to overcome any problem or difficulty that we may encounter in life; a capacity to transform any suffering. Our lives possess this power because they are inseparable from the fundamental law that underlies the workings of all life and the universe.
Nichiren, the 13th-century Buddhist monk upon whose teachings the SGI is based, awakened to this law, or principle, and named it “Nam-myoho-renge-kyo.” Through the Buddhist practice he developed, he provided a way for all people to activate it within their own lives.
Shakyamuni, the founder of Buddhism, first awoke to this law some 2,500 years ago. Discovering that the capacity to transform suffering was innate within his own life, he saw too that it is innate within all beings.
Nam-myoho-renge-kyo could be described as a vow, an expression of determination, to embrace and manifest our Buddha nature. It is a pledge to oneself to never yield to difficulties and to win over one’s suffering. At the same time, it is a vow to help others reveal this law in their own lives and achieve happiness.
NAM- comes from the Sanskrit namas, meaning to devote or dedicate oneself.
Myo- can be translated as mystic or wonderful, and ho means law. This law is called mystic because it is difficult to comprehend. What exactly makes it difficult to comprehend? It is the wonder of ordinary people, beset by delusion and suffering, awakening to the fundamental law in their own lives and realizing that they are inherently Buddhas able to solve their own problems and those of others.
Renge- means lotus blossom. The lotus flower is pure and fragrant, unsullied by the muddy water in which it grows. Similarly, the beauty and dignity of our humanity is brought forth amidst the sufferings of daily reality.
Further, unlike other plants, the lotus puts forth flowers and fruit at the same time. This illustrates the principle of the simultaneity of cause and effect; we do not have to wait to become someone perfect in the future, we can bring forth the power of the Mystic Law from within our lives at any time.
Kyo--- literally means sutra and here indicates the Mystic Law likened to a lotus flower, the fundamental law that permeates life and the universe, the eternal truth.

To chant Nam-myoho-renge-kyo is an act of faith in the Mystic Law and in the magnitude of life’s inherent possibilities. Nam-myoho-renge-kyo is not a mystical phrase that brings forth supernatural power, nor is it an entity transcending ourselves that we rely upon. It is the principle that those who live normal lives and make consistent efforts will duly triumph.

source-http://www.sgi.org/about-us/nam-myoho-renge-kyo.html