Japanese Special Defense Force personnel marched in a parade in Asaka, Japan, in a file photo. Their role in any Taiwan Straits crisis is unknown. Image: AFP Forum via EPA

When Japanese Deputy Prime Minister Taro Aso said on July 5 that Tokyo would come to Taiwan’s aid in the event of a Chinese invasion, Beijing’s sharp response was predictable.

“We will never allow anyone to meddle in the Taiwan question in any way,” Chinese Foreign Ministry spokesman Zhao Lijian said the day after Aso made his surprise remark.

“No one should underestimate the resolve, the will, and the ability of the Chinese people to defend their national sovereignty and territorial integrity.”

But Aso’s statement was no slip of the tongue. A week later, on July 13, Japan released its annual defense report, which for the first time mentioned the importance of maintaining “stability” around Taiwan because it “is important for Japan’s security.”

China’s response, again, was sharp and immediate. The Chinese Communist Party mouthpiece Global Times ran an op-ed stating that “Japan will ‘lose badly’ if it defends Taiwan secessionists.”

The piece quoted an anonymous Beijing-based military analyst as saying, “Even the US could not defeat China militarily in the West Pacific region now, so what makes Japan believe it’s able to challenge China with force?”

While the motivations behind Tokyo’s recent statements are unclear, Japan and Taiwan are openly on the same side in Asia’s intensifying new Cold War, where an increasingly assertive and militarily powerful China is the obvious but usually unspoken adversary.

Japanese Deputy Prime Minister Taro Aso is the latest top-level politician to lend rhetorical support for Taiwan. Photo: Handout / AFP via Japan Exchange Group

Japan and Taiwan do not share official diplomatic relations — Tokyo recognizes Beijing as the sole legitimate government of China — but the two sides are known to share intelligence through back channels.

In May last year, as Taiwanese President Tsai Ing-wen began her second term in office, then-chief Cabinet secretary, now prime minister, Yoshihide Suga said that Japan is eager to develop its ties with Taiwan.

Japan’s annual foreign policy report, known as the Diplomatic Bluebook, describes Taiwan in its latest edition released on April 27 this year as an “important partner and friend.” It also said Japan backs Taiwan’s campaign to attend the World Health Assembly, the decision-making body of the World Health Organization (WHO).

The Bluebook stated diplomatically that Taiwan had been successful in fighting the Covid-19 virus and “there should be no blank spaces on the world map.” China, which considers Taiwan a renegade province that should be “reunited” with the mainland, strongly opposes Taiwan’s participation in any international bodies.

The Bluebook also said that Japan would cooperate with “more countries” to promote freedom of navigation and the rule of law in the Asia-Pacific region. In matters of geostrategic importance, Japan already works closely with the US, India and Australia under the so-called “Quad.”

Taiwan could be seen as a silent partner, or at least an ally, to the strategic grouping because it is a vital link in the China-focused island chain of defense which stretches from Japan’s main islands to Okinawa, Taiwan, the Philippines and the Malaysian part of Borneo.

However, the bigger question remains: what exactly would Japan be prepared to do if China did try to invade Taiwan? Whatever the anonymous military analyst quoted in the Global Times might think, Japan certainly has the means to challenge China militarily.

On December 21, 2020, the Japanese government approved the ninth consecutive rise in military spending, marking a historic record of 5.34 trillion yen (US$51.7 billion.)

Japanese sailors aboard the Japan Maritime Self-Defense Force (JMSDF) ship JS Hyuga direct a US Marines MV-22 Osprey to land during the Dawn Blitz 2015 exercise off the coast of Southern California. Photo: AFP / Mark Ralston

Japan’s Self-Defense Forces (JSDF), as they are formally known, are comprised of nearly 250,000 active personnel and another 50,000 in reserve, and are equipped with the latest weaponry and technology procured mainly from the US.

The Japanese Navy is believed by military analysts to be the strongest in the region after America’s and thus superior to China’s still underdeveloped but steadily growing naval forces. China now has two combat-ready aircraft carriers.

According to the Washington-based think tank the Center for Strategic & International Studies, Beijing has made substantial progress in the construction of a third known as Type 003, which is “slated to become the largest surface combatant in the Chinese People’s Army Navy (PLAN) and significantly upgrade China’s naval capabilities.”

But the crux of the strategic matter is that Article 9 of Japan’s supposedly pacifist, post-World War II constitution outlaws war as a means to settle international disputes and its JSDF are therefore legally only allowed to defend the country if it comes under attack.

But Aso has argued that Taiwan is situated only 112 kilometers from some islands that are part of Okinawa prefecture and therefore a Chinese invasion could represent an “existential threat” to Japan’s security.

In that direction, the Japanese navy’s first aircraft carrier since World War II is nearly ready to deploy. It is designed to carry up to 28 light or 14 larger aircraft.

Jeffrey Hornung, a political scientist at the US-based Rand Corporation, wrote in a May 10 paper that Japan would not need to get directly involved in a military conflict over Taiwan.

But, he suggests, if Washington sought to defend the democratic, self-ruled island, “at a minimum, the United States would require access to its bases in Japan, which would execute combat operations in, over and around Taiwan.”

The JSDF would in that way “act as a force multiplier for any US-led operation. That means US requests for Japanese involvement would be almost certain.” In other words, Japan’s involvement would be limited to “non-combatant, rear-area support roles” in fields such as “supply, maintenance, transportation, engineering and medical services,” Hornung writes.

Taiwanese soldiers take aim during an annual drill a military base in the eastern city of Hualien on January 30, 2018. Taiwanese troops staged live-fire exercises on January 30 to simulate fending off an attempted invasion, as the island’s main threat China steps up pressure. Photo: AFP / Mandy Cheng

Okinawa is proximal to Taiwan and the US base there would be at the front of any military action against China.

If China decided to attack Okinawa, or for argument’s sake any base on Japanese territory, such an attack could be interpreted as an act of aggression and Japan would have the right to act in self-defense.

But that scenario also raises another important question: would the US be prepared to intervene and defend Taiwan? The US and Taiwan, officially the Republic of China, shared a defense treaty before Washington established diplomatic relations with China on January 1, 1979.

On that day, the US withdrew its recognition of the Republic of China and terminated the 1955 “Sino-American Mutual Defense Treaty between the United States and the Republic of China.” Because either party had to notify the other about the termination a year in advance, the treaty remained in place – at least nominally – until January 1, 1980.

The now null-and-void 1955 treaty, which stipulated that if one country came under attack the other would provide military support, was in certain aspects replaced by the 1979 Taiwan Relations Act.

Under the Act, the US was no longer be obliged to defend Taiwan, the US embassy in Taiwan was closed and relations were maintained through a non-profit corporation registered in the District of Columbia known as the American Institute in Taiwan (AIT), which functions as a de facto embassy.

The ambiguity of the relationship is evident in a Taiwan Relations Act clause that says that “the United States will make available to Taiwan such defense articles and defense services in such quantity as may be necessary to enable Taiwan to maintain sufficient self-defense capabilities.”

The Act’s intention appears to be to dissuade Taiwan from declaring independence from China, while at the same time discouraging China from invading Taiwan. But that all came into force when Jimmy Carter was America’s president and China was still a fairly poor country, not the regional superpower it has become today.

As Beijing celebrated the 100th anniversary of the founding of the Chinese Communist Party on July 1, President Xi Jinping reiterated his pledge to incorporate Taiwan into the mainland.

Chinese President Xi Jinping reviews a military display of Chinese People's Liberation Army (PLA) Navy in the South China Sea on April 12, 2018. Photo: Reuters/Li Gang/Xinhua
Chinese President Xi Jinping reviews a military display of Chinese People’s Liberation Army (PLA) Navy in the South China Sea on April 12, 2018. Photo: Xinhua

“Solving the Taiwan question and realizing the complete reunification of the motherland are the unswerving historical tasks of the Chinese Communist Party and the common aspiration of all Chinese people,” Xi said in a speech.  

Every Chinese must work together, “resolutely smashing any ‘Taiwan independence plots,’” the Chinese leader added. China has recently flexed its muscles in that direction with air force jets and bombers making frequent incursions into Taiwan’s airspace.

In this new geopolitical environment, it would be impossible for the US to stay idle if Xi turned his tough rhetoric into military action and actually sent forces to invade Taiwan.

In that scenario, Japan could and would not stay neutral.

To be sure, Deputy Defense Minister Aso is known for his public gaffes, which are often corrected or denied by the government after being uttered.

But as Corey Wallace, a foreign policy expert at Kanagawa University in Yokohama was quoted saying in the July 12 issue of Foreign Policy, the slip this time may have been deliberate and reflect what Japanese officials have long believed privately.

Either way, Xi is playing with certain fire by talking about Taiwan’s “reunification” with the mainland. Even with China’s recent military and naval build-up, Beijing still faces formidable odds in invading Taiwan, which would almost inevitably result in a wider conflict – one Japan would inevitably play a crucial, military role.