Japão - Dia 9 - White day

In Japan, Valentine's Day is typically observed by girls and women presenting chocolate gifts usually to boys or men. On White Day, the reverse happens: men who received a honmei-choco ("chocolate of love") or giri-choco ("courtesy chocolate") on Valentine's Day are expected to return the favor by giving gifts. Sometimes the term sanbai gaeshi ("triple the return") is used to describe the generally recited rule that the return gift should be two to three times the cost of the Valentine's gift. (aqui)