It would break your teeth and your wallet. A diamond-topped chocolate cake is among the more extravagant marketing gimmicks on offer this year as Osaka department stores kicked off their Valentine's Day confectionery sales campaigns on Tuesday.

The cake is topped with 125 diamonds and has a price tag of ¥14.1 million. It will be available from Wednesday at Takashimaya Osaka Store, when the store launches its range of Valentine's products.

The Kintetsu department store at Abeno Harukas, Japan's tallest building, has some 120 different brands of chocolate on offer, including truffles at ¥1,800 apiece.

The Hankyu Department Store in central Osaka, which will also start its Valentine's sales on Wednesday, touted a range of domestic and imported chocolate that it says is exclusive to the store.

A tradition has arise in Japan — fueled by the tireless efforts of marketers — that it is women who must purchase chocolate for Valentine's Day for the men in their lives. It is the men's turn later in the year.

This year, the department stores have focused their lineups on products for women buying for themselves. This is because Feb. 14 this year is a Sunday and they expect a drop in sales of chocolates intended to be given out at workplaces.