TAIPEI, Taiwan — Candidates for the presidency of the Republic of China on Taiwan are emphasizing the importance of peaceful relations with the Communist regime at Beijing, which has described January 13 elections on the island democracy as a choice between war and peace and stepped up harassment of the territory it claims as its own.

The frontrunner, Taiwan’s vice president from the ruling Democratic People’s Party, William Lai, said in a televised debate Saturday that he was open to communicating with the government in Beijing, which has refused to talk to him or President Tsai Ing-wen.

Beijing favors the candidate from the more China-friendly Nationalist, or Kuomintang, Party, and has criticized Mr. Lai and Ms. Tsai as “separatists” and accused them of trying to provoke a Chinese attack on Taiwan.

Taiwan split from the mainland amid the victory of Chairman Mao’s communists in China’s civil war in 1949, but Beijing continues to regard the self-governing island of 23 million with its high-tech economy as Chinese territory and has been steadily increasing its threat to achieve that goal by military force if necessary.

Tensions with China have featured strongly in the presidential campaign.

China has also stepped up military pressure on the island by sending military jets and ships near it almost daily. Taiwan’s Defense Ministry this month also reported Chinese balloons, which could be used for spying, flying in its vicinity.

Differences over Taiwan are a major flashpoint in Sino-American relations. America is bound by law to provide Taiwan with the weapons it needs to defend itself.

Mr. Lai, who tops most opinion polls, promised to help strengthen Taiwan’s defense and economy if elected.

“As long as there is equality and dignity on both sides of the Taiwan Strait, Taiwan’s door will always be open,” he said during the debate. “I am willing to conduct exchanges and cooperation with China to enhance the well-being of the people on both sides of the Taiwan Strait.”

“The international community has realized the threat China poses to Taiwan and the international community,” Mr. Lai said. “In fact, everyone is already preparing to respond. We should … unite and cooperate to ensure peace.”

The Kuomintang candidate, Hou Yu-ih, also said he sought peaceful relations with Beijing.

The Kuomintang previously endorsed unification with China but has shifted its stance in recent years as Taiwan’s electorate is increasingly identifying as Taiwanese, as opposed to Chinese, and wants to maintain the status quo in relations with Beijing.

Mr. Hou said he opposed Taiwan’s independence but also a potential unification under China’s “one country, two systems” framework, which Beijing has used to govern Hong Kong, a former British colony that returned to China in 1997. Mr. Hou said he sought “democracy and freedom” for Taiwan.

The third candidate, Ko Wen-je, from the smaller Taiwan People’s Party, referenced a quote by Secretary Blinken regarding Sino-American relations, saying that “Taiwan and China will cooperate if they can cooperate, compete if there’s a need to compete, and confront each other if they must confront each other.”

“The people on both sides of the Taiwan Strait are of the same race and have the same history, language, religion and culture, but at this stage, we have a different political system and way of life,” Ms. Ko said, adding that “Taiwan needs self-reliance, and both sides of the Taiwan Strait need peace.”

“We have to make it clear to the Chinese government that my bottom line is that Taiwan must maintain its current democratic and free political system and way of life,” Ms. Ko said. “Only if these conditions are met can we have dialogue.”