Japan, since 1948, has held an annual ceremony called the Coming-of-Age Day (成人の日; seijin no hi), the second Monday of January, for those becoming 20 years old in the new calendar year. Until 1999, the day was held on January 15. The day is a national holiday, and local governments generally hold some sort of ceremony. Women often wear furisode, a traditional Japanese formal kimono with long sleeves. Men usually wear suits, though some wear traditional Japanese clothes. At this age, the right to smoke, drink, and vote is granted . It was known as genpuku (see the section below) among samurai in the past.

[edit] Gempuku In Japan, Gempuku (元服) was a celebration that showed a samurai was considered to be an adult. The age of gempuku varied from 12 to 18.

Upon reaching this age, men usually changed their names from their birth names to adult names, changed their hair styles to an adult style by shaving the forelocks, received their first swords, and began to be treated as adults. They separated from their mothers or governesses, and they became able to take on the dominant role in shudo (male-male love) relationships. Some were even given a territory to rule. No samurai was allowed to marry before gempuku, though they could be engaged. There was no gempuku or equivalent ceremony for women. On rare occasions, gempuku was held for someone younger than 12 for the purpose of marriage. Marriage at this age was for political purposes. Shudo (衆道) is the Japanese tradition of age-structured homosexuality prevalent in samurai society from the medieval period until the end of the 19th century. ...

Alternate spellings include genpuku, gembuku, genbuku, gembaku, and genbaku.