Actress Yui Aragaki in kimono for her coming of age celebration in 2009. Coming of Age Day (Seijin no Hi) is a big event in Japan. It’s a national holiday, held annually on the second Monday of January for people who turn 20, the legal age for Japanese. Many magazines would feature these celebrities for the special occasion.
Not sure where the pictures are from, probably a magazine photoshoot. Besides Aragaki, popular actresses Erika Toda and Maki Horikita also turned adult the same year.