Are all the men at your workplace or school expecting a little chocolatey treat for Valentine's Day? Getting giri-choco ('obligation chocolate') for the boys can feel like more than a minor pain in the butt, but some enthusiastic ladies still go to great lengths even when deciding on these semi-mandatory 'presents'. Hoping to catch exactly such eager shoppers, this Black Thunder pop-up at Tokyo Station sells a wide variety of limited-edition versions of Japan's favourite 'B-grade' chocolate bar. The shop actually sold out completely last year, so you'll need to queue up just for a ticket, which then entitles you to a purchase. Obligation, indeed.