White Day is a significant cultural observance in Japan, celebrated on March 14th.
It's essentially the counterpart to Valentine's Day, which is celebrated a month earlier on February 14th. On Valentine's Day in Japan, it's customary for women to give gifts, typically chocolates, to men. White Day, on the other hand, is when men reciprocate by giving gifts, often sweets or white chocolates, to women who gave them gifts on Valentine's Day.
It's a day focused on expressing appreciation and returning the gesture of affection. This tradition originated in Japan but has also been adopted in other East Asian countries.