A 2021 Japan-U.S. joint statement that referred to the Taiwan Strait for the first time in 52 years was meant to signal Washington's commitment to the security of Asia amid China's increasing assertiveness, former Prime Minister Yoshihide Suga said recently.

In an interview with Kyodo News about one year after his April summit with U.S. President Joe Biden, Suga said that while the two countries committed to enhance deterrence under a "functioning" alliance, they also tried to send out a message that Tokyo and Washington were seeking strategic dialogue with Beijing.

Former Prime Minister Yoshihide Suga speaks in an interview with Kyodo News on April 14, 2022, in Tokyo (Kyodo)

The statement on April 16, 2021, said, "We underscore the importance of peace and stability across the Taiwan Strait and encourage the peaceful resolution of cross-strait issues."

Expecting a backlash from the Chinese leadership over the reference, the statement also said, "The United States and Japan recognized the importance of candid conversations with China."

Taiwan was previously mentioned in a U.S.-Japan leaders' statement in 1969, before Tokyo and Washington recognized Beijing as the sole legitimate government of China.

Then Japanese Prime Minister Eisaku Sato and U.S. President Richard Nixon said in the statement that "the maintenance of peace and security in the Taiwan area was also a most important factor for the security of Japan."

In the interview, Suga said he went into the summit with the stance that Japan would "respond calmly and firmly" to China's unilateral attempts to change the status quo and human rights issues involving the country, but that it was "not desirable to heighten military tensions unnecessarily" as Japan is geographically located close to China.

"I conveyed my thoughts about how Japan-China relations should be at the summit meeting," Suga said, pointing to the importance of economic ties between the two Asian countries.

Suga also revealed he had received indirectly a message from Beijing urging Tokyo to respect four basic documents between the two countries, including their 1972 joint statement, which states the Chinese government regards Taiwan as "an inalienable part" of China and that the Japanese government fully understands and respects this.

Communist-led China and democratic Taiwan have been governed separately since they split in 1949 after a civil war. China has regarded Taiwan as a renegade province to be reunified with the mainland, by force if necessary.

As Russia's invasion of Ukraine continues, Beijing and Moscow moving even closer to each other is not desirable for Asia, Suga said, adding that strategic diplomacy is needed to change China's stance. China and Russia have been reinforcing ties in recent years as their relations with Washington have deteriorated.

The former premier said that ties between the United States and the Association of Southeast Asian Nations were damaged during the administration of Biden's predecessor Donald Trump and that he urged the U.S. leader to build closer ties with ASEAN.

Suga also said he believes the Quad -- a framework involving Japan, the United States, Australia and India -- should push forward dialogue with ASEAN.

His remarks were made at a time when Japan's diplomacy under his successor Prime Minister Fumio Kishida is being tested amid the Russian invasion of Ukraine and the deteriorating security environment for Tokyo due to a rift between China and the United States as well as North Korea's missile and nuclear threats.

Suga quit as prime minister last October after serving in the post for about a year.

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