18 SFS Airmen battle for glory during Best Defender Challenge Published Dec. 13, 2023 By Airman 1st Class Melany Bermudez 18th Wing Public Affairs KADENA AIR BASE, Japan -- 18th Security Forces competed during the Best Defender Challenge on December 8, 2023. The BDC timed event consisted of a nine-mile ruck around the perimeter of the base equipped with a 30-pound pack. The tasks in the challenge were designed to push Airmen out of their comfort zones, tackling problem sets and obstacles not typically faced during their daily duties.