Be able to kill your student: chilling words from a shockingly fit 76-year-old man who bills himself as  the world's last ninja and stocks his training chamber with weapons such as throwing stars and nunchucks. Especially to a neophyte whose closest brush with martial arts was watching Bruce Lee matinees as a kid.

Keeping your focus is just one of the lessons thumped out on the mats of the Bujinkan Dojo, a cramped school outside Tokyo that is a pilgrimage site for 100,000 worldwide followers. They revere Hatsumi as the last living master of ninjutsu - the mysterious Japanese art of war practiced by black-masked assassins of yesteryear.

"He's unlimited in body, mind and spirit," says Richard VanDonk, who flew in from California to practice body throws in the dojo's warm glow of rice-paper screens and flickering votive candles. "He's a master of change."

Hatsumi (video) is the only living student of the last "fighting ninja," Toshitsugu Takamatsu, the so-called 33rd Grand Master who was a bodyguard to officials in Japanese-occupied Manchuria before World War II and fought - and won - 12 fights to the death. Legend says that during one battle, Takamatsu snatched an eyeball from a would-be Chinese bandit.