Today, today, the second Monday in Januar-ay, is Coming of Age Day in Japan.* This is a national holiday, which, according to Japanese Wikipedia, is legally dedicated to:

おとなになったことを自覚し、みずから生き抜こうとする青年を祝いはげます。

Celebrating and encouraging young people who awaken to the fact that they are adults and resolve to live their own life [i.e. rather than being a passenger in their parents' lives].

The day in its modern form was instituted in 1948, and was celebrated on the 15th of January until 2000 when the entertainingly named "Happy Monday System" (ハッピーマンデー制度) was made law and several public holidays were changed to the Xth Monday in the Yth month, instead of fixed dates, to ensure maximum three-day weekendage.**

Anyway, in Japan, coming of age happens when you turn 20. But since there are more than three hundred different days on which a person might conceivably turn 20, a given year's Coming of Age day in January applies to everyone who will, legally, come of age that year.

In other words, even after you attend your town's Coming of Age event and squeal (or exclaim in a manly fashion) over reunification with people you used to go to elementary school with, you still don't get to drink or smoke until your actual birthday. Psych!

Coming of Age Day is also an excuse to dress up. Guys get stuck with the business suit or sombre man-kimono, but girls get to wear furisode, literally "swinging sleeves": the young maiden's formal kimono with, yep, three-foot-long sleeves. These will get shorter as their wearers grow older and more married, so now's the time to enjoy them.

* 成人の日, seijin no hi, literally "adult day", where "adult" is written with kanji that mean "become" (成) and "person" (人).

** As of 2003, Marine Day, Respect For The Aged Day, and Health And Sports Day are the other holidays covered by the Happy Monday System. Heh! "Happy Monday."