Every March the 14th is "White Day" which is today.
To make more monies from Valentines day, the Japanese invented "White Day" as an excuse for men to buy candy to give to women in return for the chocolate that they received - theres even an official White Day site. Japanese culture has marketing down to a tee which encourages women to give chocolate on Valentines day.
The reason its called "White Day" is because the color of sugar (white) is the main ingredient for candy which was traditionally given on White Day. These days however, one does not have to give candy and can be white chocolate or marshmallows or condensed milk?
The term "Giri Choco"義理チョコ] is used to describe chocolate that is given as an obligation - like to ones superiors or boss. If you are managing ladies in Japan and receive chocolate from them then its probably not because she likes you but because she expects a pay rise come next evaluation season.
Has this White Day thing caught up in other parts of the world?