TAIPEI -- As China tries to isolate Taiwan diplomatically out of anger with the island's pro-independence government, Taipei is seeking to join the Trans-Pacific Partnership multilateral trade pact.

Taiwan's expectations for Japan's help in joining the regional trade-liberating framework poses a tricky diplomatic challenge for Tokyo.

For a long time, Taiwan has been cautious about expanding its relations with Japan out of fear of enraging Beijing. But the Taiwanese administration of President Tsai Ing-wen is showing signs of moving toward a shift in this policy.

In a Twitter post on June 27, Tsai made it clear that her administration is keen to participate in the TPP.

She responded to Chief Cabinet Secretary Yoshihide Suga's remarks the previous day, saying that Japan welcomes the interest of various countries and regions including Taiwan in joining the TPP.

Tsai said Suga's remarks helped boost Taiwan's confidence. She expressed her gratitude for Japan's support.

Her statement reflects her administration's wish to expand and enhance economic ties between the island and Japan.

Taiwanese Premier Lin Chuan told The Nikkei of Taiwan's continuing interest in joining the TPP free trade pact.

Tsai's tweets echo what Taiwanese Premier Lin Chuan had told The Nikkei several days earlier.

In an exclusive interview on June 23, Lin voiced Taiwan's continuing interest in joining the TPP free trade pact, even though the U.S. has withdrawn.

Saying Taiwan welcomes Japan's leadership in the TPP talks after the U.S. withdrawal, he said Taipei would be "happy" if Japan were to "invite Taiwan to come on board" when the partnership expands in the future.

But Beijing's long-standing "One China" policy remains a huge obstacle to Taiwan's ambition to raise its international profile and bolster its relationships with other countries.

The Chinese administration of President Xi Jinping is using this doctrine, together with the country's enormous diplomatic and economic clout, to isolate Taiwan.

The latest major victory for Xi's diplomatic campaign was Panama's decision in June to sever its ties with Taiwan and establish a formal relationship with Beijing.

This has reduced to 20 the number of countries that officially recognize Taiwan.

But Beijing is willing to show flexibility in implementing the "One China" policy when doing so helps nudge Taiwan toward unification with China.

During the previous pro-China government led by President Ma Ying-jeou of the Kuomintang, the Nationalist Party, Beijing tolerated Taipei's moves to conclude effective free trade agreements with Singapore and New Zealand, both of which have no formal diplomatic relations with Taiwan.

The Ma administration endorsed the so-called 1992 Consensus, which commits both China and Taiwan to a "One China" principle without defining what the term One China means, so that the island could enhance its relations with the mainland. For Taiwan, China means the "Republic of China," its official name.

But the Tsai administration, which was inaugurated in May 2016, has so far refused to fully embrace the 1992 Consensus, prompting Beijing to put stronger diplomatic pressure on the island.

Xi's Belt and Road Initiative to build extensive networks of transportation infrastructure that link China with areas along the Silk Road, the ancient trade route extending from China to Europe, so as to expand trade between the areas is partly aimed at isolating Taiwan. China's greater influence over these areas would give Beijing diplomatic leverage to prevent Taiwan from joining the TPP.

Ma Xiaoguang, spokesperson for the mainland's State Council Taiwan Affairs Office, stressed in a June 28 press conference that any move by Taiwan to join regional economic cooperation groups has to be based firmly on the One China principle.

In light of China's hardline stance concerning the issue, Lin's remarks expressing Taiwan's wish to beef up its ties with Japan could have huge implications for the diplomatic dynamics in the region.

Closer relations between Taiwan and Japan would no doubt be galling to the Chinese Communist Party, which bases its legitimacy as the ruling party on "victory in the War of Resistance Against Japan."

Complicated relationship

There is historical background to the complicated trilateral relationship among China, Taiwan and Japan. Under the 1895 Treaty of Shimonoseki, which ended the First Sino-Japanese War, China's Qing dynasty ceded Taiwan to Imperial Japan.

Beijing thinks Japan's defeat in World War II should have brought Taiwan, which was under Japan's colonial rule for half a century, back to China.

But the civil war between the Chinese Communist Party and the Kuomintang ended up in a division between the mainland and the island. Chiang Kai-shek's Republic of China government fled the mainland to Taiwan in 1949 and developments in the ensuing years led to the current situation.

China regards Taiwan as a breakaway province, and has vowed to retake it, by force if necessary.

Japan's move toward closer ties with Taiwan inevitably touches a raw nerve in China, as it reopens old wounds from its humiliating defeat in the past.

Taiwanese people hold ambivalent sentiment toward Japan, which once ruled the island as a colony. Yet, in a survey of Taiwanese conducted by the Interchange Association (now the Japan-Taiwan Exchange Association), which serves as Japan's de facto embassy in Taiwan, in July 2016, 56% of respondents cited Japan as the country they liked the most.

In 2016, some 4.16 million Taiwanese, nearly 20% of the island's population, visited Japan.

In his interview with The Nikkei, Taiwanese Premier Lin said it was a pity that Japan has been keeping a diplomatic distance from Taiwan out of consideration for Beijing.

As it joined the United Nations, Japan severed diplomatic ties with Taiwan in 1972 and forged a formal relationship with China.

To avoid incurring the wrath of Beijing, Japan has since been cautious about expanding its exchanges with Taiwan.

But Taiwan sent over 20 billion yen ($176 million) worth of donations to Japan following the devastating 2011 earthquake and tsunami.

The Japanese government, however, did not invite Taiwan to join other countries in laying wreaths during a 2012 memorial ceremony for the victims of the 2011 disaster. Tokyo was concerned about China's possible angry reaction.

But the government's decision provoked a public outcry in Japan, forcing then Prime Minister Yoshihiko Noda to apologize.

This incident led to Japan's review of the way it manages its relationship with Taiwan.

In 2016, the inauguration of the Tsai administration, which seeks to keep a respectful distance from Beijing while strengthening the island's relations with Japan and the U.S., raised expectations for an expansion of Taiwan's relations with Japan to a much higher level.

In moves symbolizing the trend, the Interchange Association earlier this year changed its name to the Japan-Taiwan Exchange Association, while its Taiwanese counterpart, the Association of East Asian Relations, was renamed the Taiwan-Japan Relations Association.

Lin welcomed the moves as positive signs of both sides' commitment to overcoming problems related to their political distance in the past.

But this does not signal any radical change in Japan's diplomatic policy.

In March, Jiro Akama, state minister for internal affairs and communications, visited Taiwan, becoming the highest-ranking government official to make a trip to the island since the two sides severed diplomatic ties in 1972.

Although he said Taiwan was a wonderful partner for Japan, Akama also stressed that the relationship with China is the most important among Japan's bilateral ties.

A senior Taiwanese politician who has long been involved in promoting the island's relations with Japan, said that when Tokyo moves to strengthen its ties with Taipei, Beijing responds with its own efforts to court the island.

He said Japan should reconsider its passive policy toward China now that its relations with Taiwan are facing a major turning point.