Originally
光棍节 (Guānggùn Jié) 'Singles' Day,' a campus joke about the four 1s in 11/11 looking like single sticks. Alibaba's Tmall (
天猫) turned it into a flagship sale day starting in 2009 and it grew into the world's largest 24-hour retail event. Now matched / extended by
京东 (JD) and other platforms; the 'day' often spans two weeks of pre-sales and discounts.