Chinese people have a "sacred mission" to ensure Taiwan is always considered part of China, a top Chinese leader said on Friday ahead of the 70th anniversary of Japan giving up control of Taiwan at the end of World War Two.
But the Nationalists had to flee to Taiwan in 1949 after losing a civil war with the Communists, who to this day insist the island is an integral part of China and have never renounced the use of force to bring it under Beijing's control.
Speaking at an event in Beijing to mark the anniversary, Yu Zhengsheng, the party's fourth-ranked leader, said Taiwan's "recovery" had "washed away the national shame" of repeated foreign invasions of China.
Since 1949, the reality that the mainland and Taiwan were part of one China had never changed, Yu said, in comments carried by the official Xinhua news agency.
"Maintaining the country's sovereignty and territorial integrity, and maintaining no changes to the position that Taiwan is part of China is a sacred mission for all the sons and daughters of China," he added.
Many people in proudly democratic Taiwan look with concern at autocratic China, and there is little support for the two to join up any time soon.
Many Taiwanese also have a broadly more positive view of Japan than people in China or Korea, saying that Japan's rule brought progress to an undeveloped island.
Taiwan will mark what it calls Retrocession Day on Sunday at an event overseen by Taiwan President Ma Ying-jeou.
Taiwan will elect a new president in January, and the frontrunner is Tsai Ing-wen from the main opposition Democratic Progressive Party (DPP), which has traditionally favoured Taiwan's formal independence.
The DPP says it believes only the island's people can decide its future. Beijing takes this to mean it wants independence.
Yu did not directly mention the election, but said people in China and Taiwan must both oppose any move to upset ties and damage rapidly improving relations.