The young men's division was founded on July 11, 1951 by second Soka Gakkai President Josei Toda. This group includes young men from ages 12-34.

"Youth, and indeed life itself, flashes by in the blink of an eye. That is why it is important for you to ask yourselves what you can do for those who are suffering, what you can do to resolve the mournful contradictions that plague society, and to boldly take on these great challenges without shunning the subsequent problems and difficulties you will inevitably face."
—Daisaku Ikeda, Faith into Action, page 81

President Ikeda writes about the Young Men's Division:
In Hall Caine's epic novel The Eternal City, the youthful revolutionary David Rossi cries out: "Be brave, be strong, be patient." Our youthful revolutionaries of kosen-rufu are forging ahead with courage, abundant self-confidence, and steadfast perseverance. As the young men's division marks its 55th anniversary this month (July 2006), I am thrilled with the vigorous progress made each day by these young champions of Soka.
—"The Light of the Century of Humanity" from the World Tribune written on July 11, 2006 the 55th anniversary of the young men's division, in the Mentor-Disciple Hall at the Soka Gakkai Headquarters

Study Material References:
The Writings of Nichiren Daishonin Volumes 1 and 2, The Human Revolution, The Wisdom of the Lotus Sutra Volumes 1-6.

You can find out more about the founding of the YMD in The Human Revolution: