A pair of 421st Combat Training Squadron instructors demonstrate Brazilian jiu jitsu techniques to students during the Field Craft - Contingency response proof of concept on Nov. 4, 2015, at Joint Base McGuire-Dix-Lakehurst, New Jersey. The 14-day training course was designed to improve how Contingency Response Airmen are trained in air base opening combat skills. (U.S. Air Force photo/Tech. Sgt. Chris Powell)