Chocolate with feelings attached

Valentine’s Day in Japan is the day when women profess their love by giving chocolates to their object of affection. However, the existence of this box reveals that chocolates are not only gifted out of love; they are also gifted out of obligation. When did this tradition start? Is it a marketing scheme created by the chocolate industry itself? How is obligatory chocolate different from regular Valentine’s chocolate? What do the Japanese people think of obligatory chocolates?