In October 1972, just five months after Okinawa had reverted to Japanese sovereignty, thousands gathered outside a Ground Self-Defense Force base that was about to open in the prefectural capital Naha to chant "Japanese army, go home." The GSDF's full-scale deployment in the prefecture was beginning with a resounding rejection.

Almost 50 years later, with pains taken to turn a fractured relationship into one of trust with residents, the GSDF in Okinawa is seen as the frontline of defense against China's growing regional threat, with a senior Defense Ministry official emphasizing its "indispensable deterrent role." But will the improved perceptions last?

In the immediate aftermath of Okinawa's reversion to Japan from the United States, the sight of GSDF personnel in uniform brought back memories for locals of the atrocities committed by the Imperial Japanese Army during the Battle of Okinawa in the closing stages of World War II.

File photo taken in April 1972 shows people protesting in Naha the deployment of the Ground Self-Defense Force in Okinawa. (Kyodo)

The battle began on March 26, 1945, with the landing of U.S. soldiers in the Kerama Islands. Around 94,000 civilians, about a quarter of Okinawa's population at the time, as well as over 94,000 Japanese soldiers and about 12,500 U.S. troops died in the fighting that lasted until June, according to the Okinawa prefectural government.

The Imperial Japanese Army drove residents from shelters, stole their food, and killed suspected spies. They also forced civilians to commit mass suicide ahead of the advance of U.S. forces.

Kunio Ishimine, 88, who as a retired GSDF member from the Okinawa town of Yomitan from 1968 helped "lay the groundwork" for the deployment in Naha, said, "It was only natural that Okinawan residents rejected the GSDF because they thought 'the Japanese army doesn't protect civilians.'"

File photo shows a Ground Self-Defense Force member raising a signboard for the opening of the Naha base in October 1972. (Kyodo)

Ishimine worked at a bank in his hometown after leaving GSDF service in Kagoshima on the island of Kyushu, but he was also involved in recruitment efforts and organized GSDF public relations film screenings in various regions of Okinawa. His role earned him criticism, and he says he even received a bomb threat at the bank.

But the backlash had been explosive from the beginning as GSDF personnel were denied apartment housing, while some local governments refused to even register them as residents.

"I was nervous whenever I went outside the gate," Makoto Nakahara, 69, a former GSDF member who worked at the Naha camp from 1975 for more than 30 years, recalled of the time after taking up his posting.

He says around 1978, a large cardboard box sent by the local government arrived at the base. A memo inside asked that small parcels containing souvenirs be handed out to all of the personnel who were coming of age, or turning 20 that year.

"We took this to mean, 'Don't come to the coming-of-age ceremony.' It was quite a shock," said Nakahara.

Supplied photo taken in April 2020 at Naha Airport shows defused unexploded bombshells collected by Ground Self-Defense Force personnel. (Photo courtesy of GSDF 15th brigade)(Kyodo)

Fast forward to today, when GSDF members might be seen surrounded by sandbags seeking to defuse one of the innumerable unexploded WWII shells still buried in Okinawa. Since 1972, they have disposed of some 1,800 tons worth of ordnance in what has become one of their main duties.

"Along with the emergency transport of patients from remote islands, the accumulation of these types of missions has led to trust with locals," Nakahara said. More than 70 percent of residents surveyed in the prefecture in 2015 held a favorable impression of the Self-Defense Forces.

According to a Ministry of Defense official, during the Cold War, although the SDF prepared for an invasion from the former Soviet Union, "there were no steps taken to bolster Okinawa due to the political risks."

But since entering the 2000s, the SDF has had no choice but to keep a wary eye on China's military buildup. China has strengthened its territorial claim to the Japan-administered Senkaku Islands in the East China Sea, a group of uninhabited islets it calls Diaoyu.

The GSDF's first combined brigade, based in Naha, was reorganized and upgraded to the 15th brigade in 2010 -- a full-fledged unit with increased personnel that has become the vanguard to protect the Nansei Islands -- a chain of islands including Okinawa stretching southwest from Kyushu toward Taiwan.

File photo shows an F-15 fighter jet scrambling, taking off from Naha Air Base in April 2015. (Kyodo)

The Air Self-Defense Force has also vastly boosted scrambles of fighter jets against Chinese aircraft approaching Japanese airspace since around 2012 when Japan nationalized the Senkakus. Tokyo deployed additional jet fighters at Naha Air Base in 2016 in response to the overwhelming pressure in the region.

It might appear that the GSDF has turned perceptions completely around and won acceptance from residents, but a top uniformed official warned that the popular mood can turn on "small things."

Describing Okinawa as key to the security pact between Japan and the United States, the official said any renewed deterioration of the relationship "could well shake the strategy for dealing with China."

In March, the GSDF and the U.S. Marine Corps held joint amphibious exercises to improve response capabilities in the defense of Japan's remote islands as China intensifies its military assertiveness in regional waters.

With May 15 marking the 50th anniversary of its reversion to Japan, Okinawa has now been forced to bear new burdens and is at the mercy of outside calculations.