Taiwanese fighter jets in training [EPA=Yonhap News Agency file photo]

It has been revealed that the Japanese government examined the military implications of a potential unification between China and Taiwan 16 years ago.

Citing sources, the Sankei Shimbun reported on the 24th that the Ministry of Defense, during the formulation of the "Defense Plan Outline" (Defense Outline) which outlines mid-to-long-term defense strategies in 2010 when the Democratic Party of Japan was in power, had reviewed the military impact of cross-strait unification on Japan.

Discussions at the time reportedly included the air superiority China would gain by being able to utilize Taiwanese ports and airports, and the impact on U.S. military support for Japan.

In such a scenario, opinions were raised that China could repurpose its air power deployed against Taiwan for operations against Japan, and also deploy aircraft with shorter ranges, according to Sankei.

On the maritime front, if China could use Taiwan's Su'ao port, it would gain a deployment base outside the First Island Chain (a line connecting Japan's Okinawa, Taiwan, the Philippines, and the Strait of Malacca), making it difficult to maintain Japan's existing maritime transport route defense plans, the newspaper added.

In conclusion, the Japanese government at the time predicted that China's operational range and available military power would expand, and its "anti-access area denial" (A2/AD) capabilities to block support from the United States and others would significantly improve.

Furthermore, it was reported that the necessity to prepare for a posture that Japan could withstand for an extended period on its own was raised, as securing the safety of sea lanes supporting U.S. military assistance to Japan would become difficult if China used Taiwan as a staging ground for an invasion of Japan.

Sankei speculates that while such scenarios were omitted from the Defense Outline established by the Democratic Party government in the same year, they became a contributing factor to former Prime Minister Shinzo Abe's push to strengthen defense capabilities upon his return to power two years later.

At the time, former Prime Minister Abe had finalized a new Defense Outline that included such considerations while pursuing a strengthening of military power to counter threats from China and other nations.

The timing of the report on the government discussions from 16 years ago, at a time when Prime Minister Sanae Takaichi's administration is accelerating defense buildup while keeping China in check, is also noteworthy.

It can be seen as an attempt to highlight that concerns about the potential paralysis of Japan's maritime transport routes in the event of a Taiwan contingency have been shared within the Japanese government since the past, amidst the deterioration of Sino-Japanese relations following Prime Minister Takaichi's remarks in November last year suggesting intervention in the event of a Taiwan contingency.

Consequently, the justification for the remarks suggesting intervention in the event of a Taiwan contingency is expected to be highlighted, and the momentum for defense buildup, including revisions to the three key security documents, is likely to gain further traction.

A defense ministry official told Sankei, "If a state of emergency occurs in Japan, a scenario where events in Taiwan have a ripple effect is the most probable."