"You can't keep a good man down" is the darkly applicable phrase that springs to mind when listening to Yasuhiro "Mark" Yamazaki. The energy, conviction, sense of mission and utter absence of self-pity in this soft-spoken man is humbling.

In 1979, the Tokyo-born Yamazaki, now 50, was attending high school in Massachusetts. It was about a year into his studies, and the students had opened the dorm windows to let some air into the building after curfew on an unseasonably warm February night.

Yamazaki was sitting on the low ledge of the hallway windows, a place students often gathered. But when he leaned back against the window grate, it broke and he fell three stories to the ground, breaking his back, fracturing his skull and severing his spinal cord. Unconscious for 10 days, Yamazaki awakened to find himself paralyzed from the waist down.