Taipei (AFP) - Ever since Communist China and Taiwan broke away from each other at the end of the Chinese Civil War in 1949, the waterway separating them has been a geopolitical flashpoint.
The Taiwan Strait, just 130 kilometres (80 miles) wide at its narrowest point, is a major international shipping channel and all that lies between democratic, self-ruled Taiwan and its giant authoritarian neighbour.
On Saturday, Beijing began three days of military drills in response to this week's visit by Taiwan President Tsai Ing-wen to the United States, where she met with US House Speaker Kevin McCarthy in Los Angeles.
China described the drills as "a stern warning" to "separatist forces" that want to bring about Taiwan's independence by colluding with foreign powers.
Following a visit to Taiwan last August by McCarthy's predecessor Nancy Pelosi, China unleashed its largest-ever military exercises around the island.Analysts had initially said that Tsai meeting McCarthy in the US may placate Beijing and avert a military show of strength.
Historians pinpoint three moments before Pelosi's visit when tensions within the Taiwan Strait boiled over into crisis.
First Taiwan Strait Crisis
Mao Zedong's communist forces successfully pushed out Chiang Kai-shek's Nationalists, who relocated to Taiwan, at the end of the Chinese Civil War.
The two rivals -- the People's Republic of China (PRC) on the mainland and the Republic of China (ROC) in Taiwan -- stood on either side of the strait .
The First Taiwan Strait Crisis broke out in August 1954 when the Nationalists placed thousands of troops on Taiwan-ruled Kinmen and Matsu, two small islands just a few miles from the mainland.
Communist China responded with artillery bombardments of the islands and the successful capture of the Yijiangshan Islands, about 400 kilometres north of Taipei.
The crisis was eventually defused but brought China and the United States to the brink of direct conflict.
Second Taiwan Strait Crisis
Fighting broke out again in 1958 as Mao's forces conducted an intense bombardment of Kinmen and Matsu in another bid to dislodge Nationalist troops.
Concerned that the loss of the islands might lead to the collapse of the Nationalists and Beijing's eventual takeover of Taiwan, US President Dwight D Eisenhower ordered his military to escort and resupply their Taiwanese allies.
The United States at one point even briefly considered deploying nuclear weapons against China.
Unable to take the offshore islands or bombard the Nationalists into submission, Beijing announced a ceasefire.
Mao's forces would still intermittently shell Kinmen up to 1979, but an otherwise tense stalemate set in.
Third Taiwan Strait Crisis
It would be another 37 years before the next crisis.
In the intervening decades, China and Taiwan both changed considerably.
China remained Communist Party-controlled following Mao's death but began a period of reform and opening up to the world.
Taiwan began shaking off Chiang's authoritarian years and evolved into a progressive democracy, with many embracing a distinctly Taiwanese -- not Chinese -- identity.
Tensions exploded again in 1995 when China began test-firing missiles in the waters around Taiwan to protest against a visit by Taiwanese President Lee Teng-hui to his alma mater university in the United States.
Beijing loathed Lee because he favoured Taiwan declaring itself an independent state.
Further missile tests were carried out a year later as Taiwan held its first direct presidential election.
The display backfired.
The United States sent two aircraft carrier groups to push China into backing down and Lee won the election by a large margin.
A year later, Newt Gingrich became the first US House speaker to visit Taiwan.
Largest-ever exercises
It took over 25 years before the next House speaker, Nancy Pelosi, went to Taiwan.
China responded by unleashing its largest-ever air and sea exercises, sending warships, missiles and fighter jets into the waters and skies around the island.
Taipei condemned the drills and missile tests as preparation for an invasion.
Less than a year later, Tsai arrived in Los Angeles to meet McCarthy, setting off another round of Chinese military exercises.
