It all started in Kobe.

As we all know the Morozoff Ltd is from Kobe so Kobe started Valentine’s Day.  For the doubters I have put an excerpt from Wikipedia.   If you have any questions, let me know in the comments.

… Morozoff Ltd. introduced the holiday for the first time in 1936, when it ran an advertisement aimed at foreigners. Later in 1953, it began promoting the giving of heart-shaped chocolates; other Japanese confectionery companies followed suit thereafter. In 1958, the Isetandepartment store ran a “Valentine sale”. Further campaigns during the 1960s popularized the custom.

The custom that only women give chocolates to men may have originated from the translation error of a chocolate-company executive during the initial campaigns. In particular, office ladies give chocolate to their co-workers. Unlike western countries, gifts such as greeting cards, candies, flowers, or dinner dates are uncommon, and most of the activity about the gifts is about giving the right amount of chocolate to each person. Japanese chocolate companies make half their annual sales during this time of the year.