Lt. Gen. Roger Turner, commander of the III Marine Expeditionary Force, second from left, shakes hands with Lt. Gen. Seiji Toriumi, commander of Japan's Western Army, at Camp Ishigaki on Ishigaki Island, Okinawa, on Sept. 17, 2025. (Brian McElhiney/Stars and Stripes)

Japan’s military buildup in the Nansei region is sending a message to an increasingly aggressive China that it will defend its economic interests and its people, according to defense experts recently.

Since 2022, Tokyo has worked toward committing 2% of Japan’s gross domestic product to defense. Much of that has focused on the Nansei, or Ryukyu, Islands that include Okinawa and stretch southwest from Kyushu to Taiwan.

Japan is concerned about the economic and defense ramifications of a conflict over Taiwan, according to experts in Asian studies and international politics. Chinese President Xi Jinping has vowed to unify self-governing Taiwan with the mainland, by force if necessary.

A successful invasion of Taiwan by China would “completely reorder the geostrategic calculation of the region and arguably the world,” according to Mark Davidson, former director of the U.S. Global Counterterrorism Communications Center.

“China would have unfettered access to the Indo-Pacific region; it would be in a position directly and easily to impede the flow of commerce and Japan’s economic lifelines,” Davidson, a professor of international politics at Temple University’s Japan Campus, said by phone Nov. 14.

The gate at the Japan Ground Self-Defense Force's Camp Ishigaki on Ishigaki Island, Okinawa, on Sept. 21, 2025. (Keishi Koja/Stars and Stripes)

Included in Japan’s record $58 billion defense budget for next year is approximately $1.14 billion for upgraded surface-to-ship missiles like the Type-12s Japan deployed in 2023 on Ishigaki Island, less than 200 miles from Taiwan.

In November, Defense Minister Shinjiro Koizumi reiterated the ministry’s intent, announced in 2022, to position a Type-03 medium-range surface-to-air missile unit at Camp Yonaguni on Japan’s westernmost island, about 70 miles from Taiwan.

Success in Taiwan could embolden China “to continue its expansionism both toward the South China Sea … and potentially toward Japanese administered territories such as Senkaku Islands or Okinawa prefecture proper,” Davidson told Stars and Stripes.

China condemns Japan’s increased defense spending as resurgent militarism.

The Nansei Islands buildup “clearly goes beyond Japan’s ‘exclusively defense-oriented’ policy,’” Chinese Foreign Ministry spokesman Lin Jian told reporters Dec. 26.

“Terms such as ‘self-defense’ and ‘counterstrike’ are used by Japanese right-wing forces to gloss over their attempt to breach the postwar international order …,” he said, according to a transcript of his remarks.

On Monday, Chinese forces encircled Taiwan for a military exercise that included actual missile launches.

This aggression “makes it clear to me that Japan is right to orient its defenses in this direction,” Davidson said.

Launchers for the Japan Ground Self-Defense Force’s Type 03 surface-to-air missile, left, and Type 12 surface-to-ship missile are displayed at Camp Ishigaki on Ishigaki Island, Sept. 17, 2025. (Brian McElhiney/Stars and Stripes)

If the U.S. gets involved in a potential Taiwan conflict, it could lead to “direct conflict expansion in Japan or a major blow to Japan’s economic and energy activities,” said Junjiro Shida, professor of international studies at Meio University in Nago city.

Japan’s response would depend on the situation, but “would likely involve, for example, a missile attack on Chinese ships attempting to land on Taiwan,” he said by email Dec. 23.

However, even in a situation considered an existential threat, Japan’s use of force would be limited, he said.

Japan’s moves are consistent with “preserving a rules-based international order,” said Sayuri Romei, senior fellow for Japan in the Indo-Pacific Program at the U.S. nonpartisan think tank German Marshall Fund.

“[Tokyo] has stated countless times that any attempts at changing it by force will not be accepted,” she said by email Nov. 30. “That is why Japan cares about the trajectory of the war in Ukraine, as it knows that Beijing will be watching that outcome closely.”

Japan’s buildup in its southernmost islands sends a message to China “that these capabilities mean that attempts to change the status quo will not be successful,” Shida said.

Stars and Stripes reporters Keishi Koja and Alex Wilson contributed to this report.