Will keys become a thing of the past?
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Will keys become a thing of the past?

If you are always losing the keys to your office, home or hotel room, perhaps you'll like the idea of your phone or watch being able to, quite literally, open doors.

As part of the BBC's Jumpstarting Japan series - meeting the Asian giant's young entrepreneurs - Mariko Oi visited a start-up making a fast-growing multi-million dollar business out of reinventing the key.