V-22 Ospreys of the Japan Ground Self-Defense Force prepare to land at Camp Ainoura, Sasebo, Nagasaki, Japan, Feb. 23, 2025. (Tyler Andrews/U.S. Marine Corps)

Japan’s army has finished a monthlong effort to move its fleet of V-22 Ospreys to a new base on the island of Kyushu as part of a military buildup in the country’s south.

The Ground Self-Defense Force moved the last of its 17 tiltrotor aircraft on Tuesday to Camp Saga, a newly constructed base in Saga prefecture, according to a Ministry of Defense news release that day. The first Osprey left Camp Kisarazu, east of Tokyo in Chiba prefecture, on July 9 .

About 200 protesters with the Local Residents Association Against the Deployment of Ospreys at Saga Airport rallied July 9 outside Camp Saga and Friday at Saga District Court, group leader Hatsuji Koga, 76, said by phone Wednesday.

“Ospreys have been crashing around the world, having many accidents; it’s a defective aircraft,” he said. “If it crashed while we’re working, it will cause enormous damage.”

Koga, a seaweed harvester from Saga city, filed a lawsuit against the government of Japan alleging the ministry improperly purchased the base land from local landowners using a two-thirds majority vote.

Several groups have written letters to Saga prefecture, a prefectural spokesman said by phone Wednesday without elaborating further. The prefecture referred the groups to the defense ministry.

The prefecture held three open meetings in December 2022 to inform residents about the plan to open the base, the spokesman said.

Some Japanese government officials may speak to the press only on condition of anonymity.

All but two of the aircraft arrived at Saga in July; the remaining pair arrived Aug. 6 and Tuesday.

One Osprey made a precautionary landing July 28 at Vice-camp Kitatokushima when a warning light illuminated during the flight to Saga from Kisarazu, according to Saga prefecture’s website. The aircraft was able to complete the flight to Saga that day.

From their new location, the tiltrotors will “establish a system” to operate in conjunction with Japan’s Amphibious Rapid Deployment Brigade at Camp Ainoura in Sasebo city, about 45 miles west, according to the ministry’s release.

The tiltrotor pilots began flight training July 28 around Camp Saga, according to a training document released by the ministry. On Aug. 5, they began flying to Japanese bases in Fukuoka, Nagasaki, Kagoshima and Kumamoto prefectures.

Unit training, including air maneuvers and ship takeoffs and landings, will begin at bases around Camp Saga, including Camp Ainoura, at an undetermined date, the document said.

A spokesman with the Kyushu Defense Bureau, an arm of the defense ministry, by phone Wednesday referred questions about operations to Camp Saga. A spokesman at Camp Saga by phone that day declined to answer questions.

Ospreys flown by the U.S. Marine Corps will not use Camp Saga, situated adjacent to the civilian Saga Airport, according to the prefecture. A 2014 request by the ministry to permit the Marines to use the base was withdrawn Oct. 29, 2015, after prefectural Gov. Yoshinori Yamaguchi sought clarification of the plan, according to minutes of a June 12 prefectural assembly meeting.