I think I need to preface the White Day explanation with the fact that Japanese culture emphasises the importance of keeping a balance in the give and take in any sort of relationship.
With that said…
The Valentines Day tradition in Japan is for women to give chocolate to men. On March 14th, White Day, men return the favor by giving women sweets. Normally, cookies and “white colored” sweets are given, but people tend to do their own thing for White Day. Depending on what you received on Valentines or your relationship with that person, it isn’t unusual to go out to dinner or give a small piece of jewelry.
Usually women will give two types of chocolate out on Valentines: 本命チョコ honmei choko (“real feeling” chocolate) and 義理チョコ giri choko (obligation chocolate). The guy who you give honmei chocolate to is someone you really like or the person you are currently seeing.
Giri choko is though… well you are obligated to give it out to the men around you that you see everyday (classmates or coworkers). There are no feeling attached. You really don’t have to give obligation chocolate, but it usually is a nice thing to do.
Depending on where you work, the expectations surrounding Valentines and White Day can be a bit crazy. In some companies, you are expected to give relatively expensive, but small, boxes of chocolate to your coworkers on Valentines. If you give out around 10-15 of them, it can easily cost 10,000 yen (around 100 USD). Keep in mind that this is almost all obligation chocolate!
For White Day some social circles or companies will insist that the men have to at least match or go over the “value” of the present received. It’s the de facto rule for gauging your present budget. This means if you got 10 small boxes of obligation chocolates on Valentines, you might have to spend more than 150 USD total to return presents to each person. In the last couple of years there has been a trend of giving small bottles of lotion or candles etc. in lieu of candy, so if a woman gives out a lot of chocolates on Valentines, she will probably get a couple of nice, small presents on White Day.
I have heard stories of some companies banning Valentines and White Day exchanges altogether because people were spending 300-400$ on giving candy to their bosses and coworkers. I think there is a lot of pressure to buy high end chocolates and candy in some industries. It’s not really because of the chocolate itself- the packaging and brand name are important when giving and receiving gifts. It’s also somewhat embarrassing to show up with mid-priced chocolate if you work in a finance or an elite company where everyone is buying Godiva or higher level chocolates. So because of the peer pressure in some places, Valentines is outlawed, and only outlaws will celebrate Valentines.
On the other hand, honmei chocolate is like a semi-subtle confession of love. This is just what I’ve heard from my friends and some magazine articles, but the type of candy the man gives back to the woman on White Day can be used to determine his feelings for her.
The more I think about it, Valentines and White Day exchanges are really unnecessarily complicated. Too many rules, and not enough eating candy.