Making the Nice-Guy Challenge A Safe One

In 2013, I made a mistake that still affects my physical abilities—everything from Okinawan weapons training to using a screwdriver.

Two students, father and son, began classes at my dojo. The son was an energetic eight-year-old. The father was a six-foot-six retired drill sergeant who’d trained in a similar style about twenty years prior, but who wanted to start again as a white belt in order to train with his son, and had observed enough of my classes to decide he wanted me as an instructor...