Human Weapon: KarateHosts Jason Chambers and Bill Duff travel to Okinawa, Japan, the home of one of the most famous and deadly martial arts, Karate.

Their journey takes them to a 600 year-old castle where they spend time practicing Iron Body Training.

An ancient temple where they learn heart-stopping vital point strikes and go through training regiments of ancient Karate masters.

And finally leading to a Kumite (sparring match) with a real black belt, and Okinawan Champion fighter.

Watch the full documentary now