The U.S. military's MV-22 Osprey aircraft has been a lightning rod for opposition to U.S. bases in Japan since 24 of them were deployed to Okinawa in 2014.

By sending eight of the tilt-rotor Ospreys to help with relief efforts for survivors of the recent earthquakes in Kyushu, both U.S. and Japanese military planners have been able to showcase an aircraft they see as necessary for Japan's defense.

When an Osprey set down last week on a sports ground in the village of Minamiaso, Kumamoto Prefecture, the first person out was a U.S. Marine Corps photographer taking pictures of Self-Defense Forces personnel unloading supplies. Within hours, the pictures were on social media.