Storms, treacherous currents, shallow waters and other factors mean there are only four months of the year in which China could mount an invasion. And there is a further complication. One to two million troops would be needed to subdue and occupy the island but, according to Chinese sources, they will not be battle-ready for at least five years

A 2018 study concludes that Taiwan on its own could fend off a Chinese invasion and it seems the People's Liberation Army believes the same. What must be considered is that Xi might launch an invasion, find he was losing and opt to go nuclear—or he might do so from the start