The drills were presided over by Taiwan President Tsai Ing-wen and watched by the visiting king of eSwatini, the African kingdom formerly known as Swaziland at the center of a diplomatic tug-of-war between Taiwan and China.
"Our armed forces' combat effectiveness is the guarantee of our national security. It is the flourishing basis of society, and it is the back-up force for our values of democracy and freedom," Tsai said at the Han Kuang drills in the central Taiwanese city of Taichung.
"So long as our armed forces are around, Taiwan will surely be around," she added.
More than 4,000 personnel and over 1,500 pieces of equipment were deployed in the annual exercise, with drones flying overhead to provide battlefield surveillance and construction workers practicing repairs to an airbase runway.
China claims self-ruled Taiwan as its sacred territory, under its "one China" policy, and Beijing has never renounced the use of force to bring what it sees as a wayward province under its control.
China's air force has conducted a series of military maneuvers near the island in recent months that Taipei has denounced as intimidation.
Tension between Taiwan and its big neighbor has increased in recent months, with China suspicious Tsai's administration wants to push for the island's formal independence.
Tsai has said she wants to maintain the status quo, but will protect Taiwan's security and not be bullied by Beijing.
Taiwan is equipped with mostly US-made weaponry and wants Washington to sell it more advanced equipment, including new fighter jets.
Military experts say the balance of power between Taiwan and China has shifted in favor of China, which could probably overwhelm the island unless US forces came quickly to its aid.
