TOKYO -- Few may remember it today, but Sept. 6, 1976, was a day unlike any other in Japan's postwar defense history.
That afternoon, an unidentified fighter jet landed without authorization at Hakodate Airport in Japan's northernmost main island of Hokkaido. What later became known as the MiG-25 Incident revealed the weakness of Japan's defense capabilities.
Back then the threat was the Soviet Union. Today, with China as the rising Asian power and tensions high over Taiwan Strait and the Senkaku Islands in the East China Sea, Japan must not allow a recurrence of such a failure.
The Japanese Self-Defense Forces (JSDF) could do nothing against the approaching Soviet jet, which flew unimpeded through its air defense radar and landed at the airport.
The MiG carried a defector, Lieutenant Viktor Belenko of the Soviet Air Force. JSDF bases in Hokkaido and the Tohoku region of northern Japan could have been devastated in an instant if the Soviets had chosen to make a retaliatory airstrike.
In 45 years since then, Japan has built up a basis in national security law for dealing with such emergencies. Its defense capabilities have also improved, but whether they can handle a military contingency remains unclear.
Defense planners in Tokyo assume that if Japanese forces can hold out for two weeks against an invading enemy, U.S. forces will rush to the aid to reinforce the defenders. During the Cold War, the Northern Army of the Ground Self-Defense Force, responsible for protecting Hokkaido, was reinforced against a possible Soviet invasion of the island.
To prepare for rising military tensions over Taiwan, Japan should first pay attention to the time frame for its own defense. At a hearing of the U.S. Senate Committee on Armed Forces in March, Adm. Philip Davidson, then commander of the U.S. Indo-Pacific Command, said it would take responding American forces almost three weeks to move from the U.S. west coast to the first island chain.
The first island chain refers to a string of islands that includes Taiwan, Okinawa and the Philippines.
A full-blown war in today's world would likely begin with paralyzing cyberattacks on command and control systems, followed by strikes by unmanned aircraft. A land invasion would come only in the final stages.
"If China attacks Taiwan, it will not do so from the opposite shore but from behind," said Japanese lawmaker Masahisa Sato, who heads foreign policy in the ruling Liberal Democratic Party.
Noting that Taiwan lies only about 110 kilometers from the island of Yonaguni in Okinawa Prefecture, Sato, a former Ground Defense Force officer, said "a Taiwan emergency would be a Japan emergency" because the two islands form the same combat theater.
Given Beijing's move to restrict democracy in Hong Kong, any attempt to change the status quo on Taiwan by force should come as no surprise. There is a risk in losing sight of this threat from an abundance of optimism.
The biggest lesson from the MiG-25 Incident is that Japan's defenses failed. Today, while diplomatic efforts to ease tensions should continue, Japan also needs a deterrent credible enough to make China judge armed clashes to be unproductive and irrational.
U.S. President Joe Biden would struggle to justify higher military spending to his Democratic Party's left wing, which he cannot afford to ignore. Under these constraints, Washington is likely to lean more heavily on Japan and other allies.
The Quad -- a security dialogue involving Japan, Australia and India -- is part of this attempt to spread out the burden. The U.S. has high hopes for Japan's contribution to the stability of situation in the Taiwan Strait.
"Japan resolved to bolster its own national defense capabilities," said a joint statement issued at Biden's summit with Japanese Prime Minister Yoshihide Suga in April. Japan cannot simply pass this commitment off as something hypothetical.
Japan's defense spending has long hovered at around 1% of its gross domestic product. Backing its summit pledge on paper with force increases would necessarily involve a major budget increase.
The stability of East Asia underpinned the business activity that allowed the Japanese economy to thrive in the postwar era. If this foundation were threatened, an economic crisis would follow. The era in which Japan could enjoy stability and safety while leaving the security of East Asia entirely to the U.S. is over.
There is a view that China will refrain from large-scale military operations before the Beijing Olympics in February 2022. Still, it is essential to prepare for a possible crisis.
To prepare for a possible Taiwan Strait crisis, Tokyo urgently needs to revise the Japan-U.S. defense guidelines and review its national security strategy, basic defense program and medium-term defense buildup plan.