A "Beijing Bikini" is when men, especially in urban or rural Chinese areas, roll up their T-shirts to expose their midriffs or even chest in hot weather to cool off.
It’s a common sight in many Chinese cities during the summer, seen as a local, informal way to deal with extreme heat and humidity, especially before the widespread use of air conditioning.
The phrase "Beijing Bikini" is tongue-in-cheek and not an official term. It gained popularity on social media and among foreigners, highlighting the visual humor of the act resembling a "bikini" style.
Typically practiced by older men (colloquially nicknamed “bare-belly uncles”), especially those engaged in manual labor or spending time outdoors in public parks, streets, or playing mahjong.
In recent years, the practice has faced criticism for being unhygienic or indecent in modern urban settings, especially as cities try to present a more “civilized” or global image.
Several Chinese cities, including Jinan, Tianjin, and Shenzhen, have banned or discouraged the practice under "civilization codes" or campaigns for public etiquette and image improvement.