The official adult age in Japan is 20. These 20-year-old boys and girls celebrated becoming an adult at Disneyland on January 14, 2013, a national holiday of "coming of age".
Here's Mainichi English, quoting Kyodo English News (1/14/2013):
1,200 attend Coming-of-Age ceremony at Tokyo Disneyland
CHIBA, Japan (Kyodo) -- Around 1,200 people turning 20 years old attended a Coming-of-Age ceremony Monday, a national holiday, at Tokyo Disneyland in Urayasu, Chiba Prefecture.
Amid falling snow, Urayasu Mayor Hideki Matsuzaki told the new adults, who were wearing festive dress, "We live in difficult times, but I hope you will change this country in cooperation with your peers."
Takeru Hirota, a 20-year-old college sophomore attending the ceremony, said, "I don't think it's hit me yet that I've come of age...I don't know about my future, but I want to make my own decisions about what I do."
It's fitting in a way for a country where young boys and girls fashion themselves like anime/manga characters with long layered hair cuts (boys) and extra-big eyes augmented by color contact lenses (girls).
(H/T reader Vyse)