US forces are conducting exercises near the Taiwan Strait.
Tips
culture
The ~180 km-wide strait separating mainland China from Taiwan. 台海 is news-headline shorthand covering everything from PLA exercises to US carrier transits; in mainland media it often frames cross-strait tensions as an internal affair.
usage
Don't confuse with 台湾 (Taiwan, the island) or 两岸 (both sides of the strait). 台海 specifically emphasizes the geographic and political space between them.
