Taiwanese opposition leader Tsai Ing-wen won a landslide victory in the island’s presidential election Saturday to become its first female leader, telling China she wants stable relations but would defend her country’s sovereignty and dignity.

Tsai vowed to work with China to maintain peace and stability across the Taiwan Strait, but Beijing responded frostily to the results, saying good relations depended on her renouncing any prospect of Taiwan ever achieving formal independence from the mainland — something she is unlikely to do.

Tsai, head of the Democratic Progressive Party (DPP), received more than 56 percent of the vote, far ahead of Eric Chu of the ruling Nationalists, or Kuomintang (KMT), with 31 percent. The DPP also won a majority in the island’s parliament, with 68 seats out of 113.

For eight years, the KMT had promised that improving ties with China would rescue Taiwan’s ailing economy. But as trade and tourism boomed, more of the benefits flowed to business tycoons than ordinary people. The economy as a whole is thought to have barely expanded by 1 percent last year.

Now, victory for the more ­independence-minded DPP raises the prospect of a new era of uncertainty in relations with China. Tsai vowed to maintain good relations with Beijing and signaled some flexibility, but she put the onus on China to meet her halfway.

A 16-year-old singer in a South Korean pop band became the center of a political storm, after she forced to make a humiliating apology to China for daring to hold Taiwan’s flag on Korean television. (Monica Akhtar/The Washington Post)

“I also want to emphasize that both sides have a responsibility to find mutually acceptable means of interaction that are based on dignity and reciprocity,” she said in a television news conference Saturday night. “We must ensure that no provocation or accidents take place.”

“Our democratic system, national identity and international space must be respected,” she said. “Any forms of suppression will harm the stability of cross-strait relations.”

But China responded with a vow to “resolutely oppose any form of separatist activities seeking ‘Taiwan independence’ ” and with a demand that Tsai renounce the idea.

“On major issues of principle concerning national sovereignty and territorial integrity, our will is firm as rock and our attitude is consistent,” China’s Taiwan Affairs Office said in a statement. “We are willing to strengthen contact and exchange with any parties and groups that recognize that the two sides belong to one China.”

On China’s Sina Weibo micro­blogging site, Tsai’s name and the phrase “Taiwan elections” were both blocked.

On the surface, this election was all about current President Ma Ying-jeou’s failure to breathe life back into one of Asia’s former economic tigers. But at a deeper level, the vote was about Taiwan’s efforts to find its feet after two decades as a democracy and reimagine itself as a nation quite separate from its Communist big brother across the Taiwan Strait.

“Our democratic system, national identity and international space must be respected,” Tsai says. (Damir Sagolj/Reuters)

“Regardless of how you voted, the exercise of democratic expression was the most important meaning of this election,” Tsai told the Taiwanese people in the televised news conference, before addressing thousands of cheering and flag-waving supporters in central Taipei.

Forty-year-old bank teller Chang Bi-hua said she had cried as the crowd chanted, “Hello, president.” Her friend Wesley Peng said the result had been expected but was still exciting and offered the chance for a “bright future,” a sentiment echoed by many. “Everybody is very excited about the change,” said 32-year-old Danny Lin. “Democracy in Taiwan has been noticed across the world — that’s a national value of Taiwan.”

Tsai focused her campaign resolutely on domestic concerns, employment and housing, modernizing the economy and forming a government that is closer to the people. But China loomed like a shadow over the election.

The question of how Beijing would react to a Tsai presidency was something the KMT tried to exploit, warning of “chaos” and “catastrophe” if she should win.

Yet most voters were obviously not swayed by that argument. That was partly because many had grown uncomfortable with Taiwan’s growing dependence on China under Ma and partly because they trust Tsai to handle cross-strait relations sensibly but also because her victory would reflect a fundamental shift in the way Taiwanese people think of themselves, experts say.

More and more, the people of this island think of themselves not as Chinese people, nor even so much as both Taiwanese and Chinese, but as exclusively Taiwanese, polls indicate.

It is a process that got underway after Taiwan became a democracy, and that has accelerated as ties with China have blossomed under Ma’s presidency.

“The more contact people have had with China, the more they feel: ‘China’s great, but it’s just not us,’ ” said Nathan Batto, an assistant research fellow at Academia Sinica in Taipei.

The issue of Taiwan’s identity and its unequal relationship with China was also inflamed on election day, after a 16-year-old Taiwanese pop singer was forced to make a humiliating apology to China for waving a Taiwanese flag on Korean television. Chou Tzu-yu was apparently forced to affirm her commitment to “one China” by her South Korean management company, concerned that it would damage her sales in China.

Tsai said the incident shook Taiwanese society and angered many people, regardless of their political views. “This particular incident will serve as a constant reminder to me of the importance of our country’s strength and unity to those outside our borders,” she said.

Some of Tsai’s supporters openly declared their desire for an independent homeland, yet others prefer the middle ground that Tsai has chalked out.

“Tsai is an intelligent woman,” said Gine Shuen, a 37-year-old teacher. “Although she is the leader of the DPP, she doesn’t insist on separating Taiwan from China, nor on making Taiwan too close to China. She keeps an open mind, wants communication and has a tolerant attitude, which is the best way to deal with the cross-strait relationship.”

Xu Jing contributed to this report.