In 1873, the empress of Japan made a radical beauty statement, appearing in public with white teeth. For centuries, tooth blackening, known as ohaguro, signified wealth and sexual maturity especially for women in Japanese society, and they would drink an iron-based black dye tempered with cinnamon and other aromatic spices to achieve the lacquered look. But as part of the Japanese government's initiative to modernize the formerly secluded island nation in the late 19th century, it banned ohaguro in 1870, and the sight of the empress with pearly whites rather than pearly blacks not only demonstrated dental solidarity with the law, but also persuaded Japanese women to follow suit, and by the 1910s, tooth blackening was a rare sight in urban areas.
Although the origin of ohaguro is unknown, its meaning is rich with both practical and symbolic purpose. For one thing, blackened teeth generally held up against decay better than untreated teeth. A 2006 study of tooth blackening among older Kammu women in Laos and Vietnam further suggests that it could help ward off sickness, as it found that soot from certain nuts and wood they applied to their teeth were resistant to certain strains of streptococcus bacteria.
The preference for darkened smiles also reflected women's societal submission to men. Beauty scholar Victoria Sherrow, for instance, notes that ohaguro "was primarily a means to hide a woman's mouth expressions, something that was also achieved by graceful movements of the hand or a fan." In a fascinating post on tooth blackening in Southeast Asia at The Gloss, Erin L. Thompson, similarly connects ohaguro to "the cultural practice, still widespread in Asia, of women holding their hands in front of their mouths while laughing."
Nor was tooth blackening confined to Japan. Thompson's research located it in "Micronesia, Melanesia, in Southeast Asia from Sumatra to Timor, and from Malaysia to China and northwest India as well as Japan and Taiwan," and Sherrow found a South American tribe that chewed a particular tree bark for its tooth-inking effects. Even today, tooth blackening still exists in some rural communities in Vietnam, though, as with Japan, Western influence largely scrubbed it out in the early 20th century.