As many people know from Anime, Valentine’s Day in Japan is the day that girls give boys chocolate, which is the opposite of the US. There are two types of chocolates that girls will give. One is called 義理チョコ（ぎりちょこ), Giri-choco.
This one is given to anyone, since Giri means “obligation,” and people often use Giri-choco as the way to show their appreciation of daily care. Thus, Giri-choco is usually given to bosses, co-workers, friends and so on. The other is 本命チョコ（ほんめんちょこ), Honmei-choco, which girls give to the boy who she truly loves. Honmei means “the favorite” and is given to the girls favorite boy to date in the school. So when a girl gives the Honmei-choco, she is saying “I like you, and I would like to date you” at the same time. If the boy receives the chocolate, it will be a happy end. If he does not, well, a little bitter memory has just been recorded.
Also, it is very reasonable for us to expect the Honmei-choco is more gorgeous than Giri-choco. Usually Honmei-choco is hand-made and very big because girls put all their love into it. In contrast, Giri-choco is relatively boring and small, and usually you can find it in supermarket. So people distinguish the Honmei-choco and Giri-choco by the size of chocolate and how elaborate it is.
There is a song called Chocolate Disco, and it describes how boys and girls interact on the Valentine’s Day. I guess it is called Chocolate DISCO because the action of boys wondering if they will receive chocolates, and girls plans about how and who they are going to give them to on the Valentine’s Day is just like a dance. It is sung by Perfume (pronounced Pahyuumu in Japanese), a very very very cute Japanese female singer group.
Also, we have the White Day which is the day for boys who received chocolates on Valentine’s Day to give the girls chocolate back. It is on March 14th, a month later than the Valentine’s Day. It is also a popular holiday because the boys who receive the Giri-choco HAVE TO give chocolate back to the girls, if they do not want to have a really bad reputation among girls. Giri-choco is now used as a tool for people to be more sociable with others. Ironically, the girls who gave the Honmei-choco often do not receive chocolates on the White Day. One is because some of them did not succeed on Valentine’s Day. The other is because although some of them succeed, once they start dating, boys can give them other special gifts on the White rather than chocolates.
Happy Valentine’s Day!!!ヽ(▽＾〃ヽ)ヽ(〃＾▽＾〃)ﾉ(ﾉ〃＾▽)ﾉ ﾜｰｲﾜｰｲﾜｰｲ♪