Younger Sister’s Day in Japan Date in the current year: September 6, 2024

Younger Sister’s Day was created by Japanese manga artist Kunio Hatada. In addition to creating manga, he researched sibling relationships and published several works covering the results his research, such as The Power of Younger Sisters: A Sociological Study. Hatada found that many women who succeeded in areas such as entertainment and sports were younger sisters, and he decided to create a holiday to celebrate their accomplishments.

Hatada chose the date for the new holiday with the help of astrology. He believed that the astrological sign of Virgo was the perfect representation of little sisters, who are generally thought to be sweet and universally beloved. September 6 was chosen because it is exactly one day before the constellation Virgo is halfway through its commonly accepted duration, from August 23 to September 22. In 1992, a special committee was created to promote Younger Sister’s Day.

One of the main highlights of Younger Sister’s Day in Japan is an annual competition titled Japan’s Little Sister Grand Prix. Its past winners have included Yuko Arimori and Gin Kanie. Yuko Arimori is a Japanese professional marathon runner who won the silver medal at the 1992 Summer Olympics in Barcelona and the bronze medal at the 1996 Summer Olympics in Atlanta. Gin Kanie was the younger of the Kinsan Ginsan identical twin sisters, who were national celebrities in Japan due to being the oldest living twins.

Younger Sister’s Day is widely celebrated by Japanese animations studios and streaming services that use it to promote their titles that have younger sister characters. For example, in 2018, NAZ revealed the character sheets and voice cast for their upcoming anime adaptation of the light novel series My Sister, My Writer.

In 2019, the streaming service AbemaTV aired a special consecutive run of two anime series featuring little sisters, Oreimo and Eromanga Sensei. The next year, the service announced that two more series featuring younger sister characters, Himouto! Umaru-chan and Yosuga no Sora, would be added to their Younger Sister’s Day special broadcast, available for free.

You can observe Younger Sister’s Day even if you’re not in Japan because younger sisters around the globe deserve to be celebrated. Give your younger sister a present or a greeting card, have a lunch with her, and share some of the happiest memories with your younger sister on social media with the hashtag #YoungerSistersDay.