Black Day is an informal holiday observed in South Korea every April 14, primarily celebrated by singles who did not receive gifts on Valentine's Day or White Day. On this day, individuals typically wear black clothing and gather to eat jajangmyeon, a noodle dish topped with black soybean paste, which symbolizes the holiday through its dark color. Businesses take advantage of Black Day by hosting various promotional events, including speed dating, matchmaking activities, and jajangmyeon-eating contests. The holiday serves as a counterpart to Valentine's Day and White Day, which involve gift-giving between genders. Black Day highlights the cultural significance of singles in South Korea, similar to how Singles Day is celebrated in China on November 11.