Our Story

Mamoru Martial Arts started in 2020 when founder Alexander Greenfield felt spiritually prompted to return to judo during the pandemic. His father became the first investor, purchasing the dojo's initial mats. The school has grown to serve around 100 students half from BYU Idaho and half from families across Rexburg, Sugar City, St. Anthony, Ashton, and Rigby. Offering judo, taekwondo, yoga, and Tai Chi, the dojo creates a welcoming space where college students train alongside local families. Named after Alex's first sensei, Mamoru Shimamoto, a distinguished Japanese judo champion, "Mamoru" means protector reflecting the school's mission to help students build confidence, discipline, and meaningful connections. What began as a pandemic impression has become a thriving community across eastern Idaho.