Taiwan on Monday started a computerised wargame simulating a D-Day style attack by China, the defence ministry said.
During the five-day drill, Chinese forces attack the island from Guangzhou and Nanjing, the military districts nearest Taiwan, while Taiwanese forces test counterattack strategies.
"The purpose of the drill is aimed to test our defence capabilities in case the People's Liberation Army launched an invasion," a defence ministry official said, declining to provide details.
Ties between Taipei and Beijing have improved markedly since President Ma Ying-jeou of the China-friendly Kuomintang came to power in 2008, pledging to boost trade links and allowing more Chinese tourists to visit.
still refuses to rule out the use of force against the island should it formally declare independence, although Taiwan has governed itself since China's civil war ended in 1949.
Ma has vowed to build stronger armed forces to serve as a deterrent against aggression from Beijing, while also promising to push for a peace treaty to end more than six decades of hostilities