China regards Taiwan, which lies 160 kilometers (100 miles) off its east coast, as a renegade province. Taiwanese are increasingly asserting an independent identity despite the population's mostly Chinese roots.
The election pits President Tsai Ing-wen of the pro-independence Democratic Progressive Party against challenger Han Kuo-yu, a populist mayor from the China-friendly Nationalist Party. A third-party candidate, James Soong, is also running.
WHAT IS TAIWAN? Taiwan, whose more than 23 million people are squeezed onto a mostly mountainous island roughly the size of Maryland, has only 15 diplomatic allies, all smaller nations. However, it issues its own passports, has a foreign minister and maintains its own military and legal system. Economically, it is an important hub in the global high-tech supply chain.
HOW DID IT COME TO BE? Most of the island's residents are descendants of migrants who began arriving from China's Fujian province in the 1600s, when Taiwan was a Dutch colony. The emigration flow grew after Taiwan was incorporated into China under the Qing Dynasty later in the 17th century, but Taiwan was not given formal status as a Chinese province until 1885. A decade later, it was transferred to Japan, which ruled it as a colony until the end of World War II. It then split again from China in 1949 after Chiang Kai-shek relocated his Nationalist government to the island after being driven off the mainland by Mao Zedong's communists. Aiming to retake power on the mainland, Chiang and his son, Chiang Ching-kuo, maintained martial law on the island until 1987, when the democratic opposition began to gather its strength.
RELATIONS WITH CHINA Talks in 1992 ended the long, formal silence between Taipei and Beijing, but tensions have risen and fallen since then. Fearful that Taiwan was headed for a declaration of formal independence, China lobbed ballistic missiles into the seas north and south of the island ahead of the first fully democratic presidential election in 1996. The tactic was seen as backfiring badly, with China's bete noire, the pro-independence Lee Teng-hui, winning handily and the U.S. Navy deploying two aircraft carrier battle groups in waters near the island in a demonstration of Washington's determination to follow through on its own legal requirement to consider threats to Taiwan a matter of grave concern.
NO TALKS Beijing claims Taiwan as its own territory, to be annexed by force if it deems necessary. It demands that Taiwan recognize the 1992 consensus that it says recognized Taiwan and the mainland as part of a single Chinese nation, though defined separately as the People's Republic of China or the Republic of China, Taiwan's official name. Tsai has refused to do so, maintaining that Beijing has no claim over Taiwan. Her government has repeatedly called for the reopening of talks between the sides, but without this or any other preconditions.
ELECTION STAKES A win by Tsai would likely lead to more diplomatic, economic and military pressure on the island in a continuation of Beijing's campaign to compel her government to agree that Taiwan is a part of China. Han is not expected to win, but his Nationalist Party is fighting to overturn the majority held by Tsai's Democratic Progressive Party in the 113-seat parliament.