White Day was first celebrated in 1978 in Japan.

It was started by the National Confectionery Industry Association as an "answer day" to Valentine's Day. 

They thought men should pay back the women who gave them chocolate and other gifts on Valentine's Day.

In 1977, a Fukuoka-based confectionery company, marketed the sale of marshmallows to men on March 14, calling it Marshmallow Day. Although the sold a lot of Marshmallows they decided to change the name and began selling white chocolate.  Now, men give both white and dark chocolate, as well as other gifts, such as sentimental things, or underwear, to the women they received chocolate from on Valentine's Day

Cynthia asked, "In Japan Valentines day is for women to give presents (mainly chocolates) to men they are fond of or are in love with right?"

Tee answered:  "Actually, most of the time it is "Giri-choco"!  This means that he gets chocolate from a person who doesn’t love him. So when he gives a present back on White Day its because he has to. Not because he loves her!

Sometime we give chocolate to our friends or to say Thank you but in general, the men are supposed to return gifts to women on the 14^th of March!

In Korea they celebrate the 14^th of every month with something!

January 14 is Candle Day.

February 14 is Valentine's Day

March 14 is White Day.

April 14 is known as Black Day.

May14 is known as Rose Day.

June 14th is Kiss Day.

July 14th is known as Sliver Day.

August 14th is known as Green Day.

September 14th is known as Music Day.

October 14th is known as wine Day.

November 14th is known as Movie Day.

December 14th is known as Hug Day

Source: Wikipedia