I didn’t learn about International Women’s Day until I moved to Hong Kong. While it wasn’t a popular holiday there, my classmates from China always wished me a Happy International Women’s Day on March 8th.
Interestingly, according to danwei.org:
March 8, or ‘san ba’ in Chinese is International Women’s Day, a holiday that is traditionally celebrated with much official support in China. But ‘san ba’ is also a rather insulting way to refer to a woman… The country that wants women to hold up half the sky uses the date of their own holiday to put them down.