Sergeant Major of the Marine Corps Sgt. Maj. Troy E. Black addresses Marines at Marine Corps Air Station Iwakuni, Japan, Aug. 21, 2019. Black visited MCAS Iwakuni during a tour of Marine Corps installations around the globe. The visit was conducted in order to provide guidance to Marines after the appointment of a new commandant and sergeant major. - Sergeant Major of the Marine Corps Sgt. Maj. Troy E. Black addresses Marines at Marine Corps Air Station Iwakuni, Japan, Aug. 21, 2019. Black visited MCAS Iwakuni during a tour of Marine Corps installations around the globe. The visit was conducted in order to provide guidance to Marines after the appointment of a new commandant and sergeant major.