Little Sister Day (Imōto no Hi)

What Is Little Sister Day?

September 6th is "Little Sister Day" (Imōto no Hi) in Japan. It was established in 1991 by Kunio Hatada (1944–1996), a manga artist who was also known for writing about "sibling types"—how birth order relates to personality. The date was chosen because it is the day before the midpoint of the Virgo period (August 23 to September 22), a sign he saw as symbolizing the charm of little sisters. It is a day to think about the little sisters in our lives and to thank them.

Born from Writing on "Sibling Types"

Kunio Hatada wrote many books about how being an older brother, older sister, younger brother, or younger sister relates to one's character and compatibility with others.

• His books: They include Shimai-gata no Hakken! (1987) and "Imōto no Chikara" Shakaigaku (1991). He also served as organizer of a society devoted to "sister types."
• Many successful women are younger sisters: Hatada believed that many women who excelled in sports and entertainment were younger sisters, and he created this day to shine a light on them.
• His work as a manga artist: His self-published Uchūsen Noah (1973) won the grand prize of the Japan Cartoonists Association Award.

There Are Days for Brothers and Older Sisters, Too

Besides Little Sister Day, Hatada created a day for each type of sibling.

• Older Brother Day (June 6): Based on the midpoint of the Gemini period.
• Younger Brother Day (March 6): Set three months before Older Brother Day.
• Older Sister Day (December 6): Established in 1992. It is regarded as the day of death of Saint Nicholas, known for the legend of saving three sisters, and falls three months after Little Sister Day.

Fascinating Facts About "Little Sisters"

• The Japan Little Sister Award: On this day, an award has been given to "little sisters" who were active that year. Recipients include marathon runner Yuko Arimori, swimmer Kyoko Iwasaki, and Gin Kanie, the younger of the famous centenarian twins "Kin-san Gin-san."
• The origin of "imōto": The word imōto is said to come from imohito. In old Japanese, imo referred to a man's sister regardless of age, and in works such as the Man'yōshū it was also used by men as an affectionate term for a wife or lover.
• No single English word: English says "younger sister" or "little sister"; there is no single word that matches imōto.
• Little sisters in popular culture: From Kaguya-hime's 1974 song "Imōto" and the 1994 drama Imōto yo to the manga Himouto! Umaru-chan, works about little sisters appear in every era.

Ideas for Little Sister Day

• If you have a little sister, send her a short message or a favorite treat.
• Thank a junior colleague or teammate who is like a little sister to you.
• Chat with family or coworkers about whether each of you is an older or younger sibling.
• Enjoy a movie, drama, or book about brothers and sisters.

A Day to Say "Thank You" to Someone Close

Little Sister Day on September 6th is a day to think of the little sister who is always nearby—or who is still family even when living far away. Together with the days for older brothers, older sisters, and younger brothers, it gives us four chances a year to remember our siblings. A single message might lead to an unexpected conversation.