Could a lie told a thousand times become a truth?
Yes, it could. That is what China believes in, and attempts to concoct regarding Taiwan's sovereignty. China has been entertaining vengeance against Japan and the West, for both have abused China in the past. Unable to take revenge on either country, China instead turned its anger on Taiwan, a small chip that China once abandoned and now claims as part of its territory. However, the claim stands on thin ice and must be refuted with facts.
Geometry says that a platform requires a minimum of three pillars to stand firmly on the globe. How many pillars support China's claim of title to Taiwan? Zero.
In 1895, by signing the Treaty of Shimonoseki with Japan as a result of defeat in a Sino-Japanese war, China ceded Taiwan to Japan in perpetuity, in addition to paying huge amounts of monetary compensation.
In 1943, the Cairo Declaration, a joint statement slightly better than a press release with no legal power, was issued expressing the common intent of restoring Taiwan to China after the war as a condition enticing China to pin down Japanese forces on the Asian continent.
In 1945, World War II ended with Japan's defeat and surrender to the Allied powers. The Chinese Nationalist Party (KMT) government was assigned by the Allied powers as their agent to administer Taiwan.
In 1949, defeated by the Chinese Communists, the KMT took refuge in Taiwan. The KMT was supposed to be an agent of the Allied powers, but they began a reign of terror. Meanwhile, the communists declared the establishment of the People's Republic of China (PRC) government in Beijing.
In 1950, the Korean War broke out. US president Harry Truman dispatched the Seventh Fleet to the Taiwan Strait.
In 1951, by signing the San Francisco Peace Treaty (SFPT), Japan renounced its title to Taiwan. That treaty, however, did not nullify the Treaty of Shimonoseki. In essence, Taiwan's legal status did not revert to what it was prior to the signing of the Treaty of Shimonoseki.
Furthermore, neither the Republic of China (ROC) government nor the PRC government represented the state of China in drafting or concluding the treaty. The treaty, which entered into effect in 1952, completely overrode the Cairo Declaration and excluded China from issues pertaining to Taiwan.
In 1952, after the SFPT took effect, the ROC government taking refuge in Taiwan signed a Treaty of Peace with Japan reaffirming the terms of SFPT. However, the ROC government was at that time not representing Taiwan in any legal capacity.
In 1971, the PRC government replaced the ROC government as the sole representative of China in the UN.
In 1972, following US president Richard Nixon's visit to China, the US government and the PRC government issued the Shanghai Communique. It contains, however, statements of disagreement in which both the US and China staked out incongruent positions. The US government only acknowledged that China claimed title to Taiwan.
In 1978, the PRC government signed a Treaty of Peace and Friendship with Japan. No provision of the treaty deals with title to Taiwan. In the same year, the US derecognized the ROC government and established formal diplomatic ties with the PRC government.
In 1979, the US Congress passed the Taiwan Relations Act, a domestic law for handling all affairs with Taiwan.