An oblique tooth is viewed in the States as requiring straightening, but in Japan it may be thought of as emblematic of a young woman's charm. While a slim body is a prerequisite for beauty today, plump women were considered beautiful in Tang Dynasty China and Heian period Japan. Starting from around the twelfth century in China, bound feet symbolized the attractiveness of women. But Japan, which received sundry influences from China, never adopted foot-binding. Instead, shaving eyebrows and blackening teeth became markers of feminine beauty. Before modern times, neither Japanese nor Chinese paid much attention to double eyelids, but in the course of the long twentieth century they became a standard for distinguishing beautiful from plain women. Thus, criteria of beauty greatly differ by era and culture, and therein lie many riddles.