Explainer: Why is Taiwan an inalienable part of China?

The Eastern Theater Command of the Chinese People's Liberation Army started two-day joint military drills surrounding the island of Taiwan on Thursday, in a strong response to "pro-independence" remarks by Taiwan region's new leader, Lai Ching-te.

The Command said the drills serve as a resolute punishment for the separatist acts of "Taiwan independence" forces and a stern warning against interference and provocation by external forces.

The State Council Taiwan Affairs Office said Lai's speech, which described Taiwan as a "sovereign, independent nation" and called for extensive collaboration with external forces to pursue "independence" and "counter the threat" posed by the Chinese mainland, was a confession of "Taiwan independence" that poses a serious challenge to the one-China principle.

What has caused the Taiwan question? And why is Taiwan an inalienable part of China's territory? Here are some facts you should know.

Taiwan has been part of China since ancient times

Taiwan has belonged to China since ancient times. The earliest written account of Taiwan was in the Seaboard Geographic Gazetteer, compiled more than 1,700 years ago by Shen Ying of the State of Wu during the period of the Three Kingdoms.

Starting as early as the mid-12th century, Chinese governments of different periods set up administrative bodies to exercise jurisdiction over Taiwan.

The Song Dynasty set up a garrison in Penghu, putting the territory under the jurisdiction of Jinjiang County of Fujian's Quanzhou Prefecture. The Yuan Dynasty installed an agency of patrol and inspection in Penghu to administer the territory. During the mid- and late-16th century the Ming Dynasty reinstated the once abolished agency and sent reinforcements to Penghu to ward off foreign invaders.

In 1662 (under Qing Emperor Kangxi), General Zheng Chenggong established Chengtian Prefecture on Taiwan. Subsequently, the Qing Dynasty government expanded the administrative structure in Taiwan. In 1727 (under Qing Emperor Yongzheng), the administration on the island was reconstituted as the Prefecture Administration of Taiwan and incorporated the new Penghu Canton. The territory then became officially known as Taiwan. In 1885 (under Qing Emperor Guangxu), the government formally made Taiwan a full province.

Taiwan was ceded due to Japan's aggression

However, through a war of aggression against China in April 1895, Japan forced the defeated Qing government to cede Taiwan and the Penghu Islands.

In July 1937, Japan launched an all-out war of aggression against China. In December 1941, the Chinese government issued a declaration of war against Japan, announcing to the world that all treaties, conventions, agreements and contracts regarding relations between China and Japan had been abrogated, and that China would recover Taiwan and the Penghu Islands.

In December 1943, the Cairo Declaration was issued by the Chinese, U.S. and British governments, stipulating that Japan should return to China all the territories it had stolen from the Chinese, including northeast China, Taiwan and the Penghu Islands.

The Potsdam Proclamation, signed by China, the U.S. and Britain in 1945 (later adhered to by the Soviet Union), stipulated that, "The terms of the Cairo Declaration shall be carried out." In August 1945, Japan surrendered and promised that it would faithfully fulfill the obligations laid out in the Potsdam Proclamation.

On October 25, 1945, the Chinese government recovered Taiwan and the Penghu Islands, resuming the exercise of sovereignty over Taiwan. From that point forward, China had recovered Taiwan de jure and de facto through a host of documents with international legal effect.

Two sides of the Straits belong to one China

On October 1, 1949, the People's Republic of China (PRC) was founded. The new government replaced the previous Kuomintang (KMT) regime, becoming the successor to the Republic of China (1912-1949) and the only legitimate government of the whole of China.

As a natural result, the government of the PRC should enjoy and exercise China's full sovereignty, which includes its sovereignty over Taiwan, according to a white paper titled "The Taiwan Question and China's Reunification in the New Era," published by the Chinese government in 2022.

Chinese Foreign Minister Wang Yi has stated that the Cairo Declaration and the Potsdam Proclamation with international legal effect constitute an integral part of the post-WWII international order, and also lay down the historical and legal foundation that Taiwan is an inalienable part of China's territory.

Speaking on the sidelines of the Munich Security Conference in February, Wang said all these facts have fully demonstrated that the Taiwan question is one hundred percent China's internal matter, calling it an unsettled question since the Chinese civil war.

"Taiwan has never been and will never be a country," he said. "This is a basic historical fact and an international consensus."

Xi Jinping, general secretary of the Communist Party of China Central Committee, has stressed on many occasions that the one-China principle is the political foundation for cross-Straits relations.

Xi said that compatriots from both sides of the Taiwan Straits belong to the same Chinese nation during a meeting with Ma Ying-jeou, former chairman of the Chinese KMT party, last month.

"The over-5,000-year history of the Chinese nation recorded successive generations of ancestors moving and settling down in Taiwan, and people from across the Straits fighting side by side to recover the island from foreign invaders," Xi said.

"The distance of the Straits cannot sever the bond of kinship between compatriots from across the Straits, and the difference in systems does not alter the reality that both sides of the Straits belong to one China, and external interference cannot hold back the historical trend of national reunification," he said.