As the communist revolution gained pace in 1920s China, women bobbed their hair short as a sign of liberation. It was a high-risk move: Those sporting the cut were easily identifiable as rebel forces, and many were executed.

This was not the first time in China that having the wrong haircut had proved deadly. From the 17th to the early 20th century, men were obliged to wear their hair in a distinctive style known as the queue: totally shaved at the front, and pulled together in a long braid at the back. Introduced by the Manchu people—the conquering force that charged into China in 1618 and established the 250-year Qing dynasty—the hairstyle was a marker of servitude imposed on everyone who fell under their domain, even the Korean king. The punishment for non-compliance was execu...