As SGI President Ikeda explains it: “Kosen means ‘to widely declare.’ Widely implies speaking out to the world, to an ever-greater number and ever-broader spectrum of people. Declare means ‘to proclaim one’s ideals, principles and philosophy.’ The ru of rufu means ‘a current like that of a great river.’ And fu means ‘to spread out like a roll of cloth.’
“The teaching of the Mystic Law has nothing to do with appearance, form or pride. It flows out freely to all humanity the world over. Like a cloth unfolding, it spreads out and covers all. So rufu means ‘to flow freely, to reach all.’
“Just like a cloth, kosen-rufu is woven from vertical and horizontal threads. The vertical threads represent the passing of Nichiren Daishonin’s teaching from mentor to disciple, parent to child, senior to junior. The horizontal threads represent the impartial spread of this teaching, transcending national borders, social classes and all other distinctions. Simply put, kosen-rufu is the movement to communicate the ultimate way to happiness—to communicate the highest principle of peace to people of all classes and nations through the correct philosophy and teaching of Nichiren” (June 5, 1998, World Tribune, p. 7).
A passage from the “Former Affairs of the Bodhisattva Medicine King,” the 23rd chapter of the Lotus Sutra, reads, “After I [Shakyamuni Buddha] have passed into extinction, in the last five hundred year period you must spread it abroad widely [kosen-rufu] throughout Jambudvipa [the world] and never allow it to be cut off” (The Lotus Sutra, p. 288).Nichiren Daishonin made it his lifelong mission to fulfill this injunction of the Buddha—kosen-rufu. He saw the fulfillment of that mission as widely propagating his teaching of Nam-myoho-renge-kyo, which he identified as the essence of the Lotus Sutra. In his “The Selection of the Time,” Nichiren wrote, “Can there be any doubt that, after this period described in the Great Collection Sutra when ‘the pure Law will become obscured and lost,’ the great pure Law of the Lotus Sutra will be spread far and wide [kosen-rufu] throughout Japan and all the other countries of Jambudvipa?” (The Writings of Nichiren Daishonin, vol. 1, p. 550).And in “The True Aspect of All Phenomena,” he wrote, “At the time when the Law has spread far and wide [kosen-rufu], the entire Japanese nation will chant Nam-myoho-renge-kyo, as surely as an arrow aimed at the earth cannot miss the target” (WND-1, 385).