Way too busy to waste any time, on-the-go commuters stream through Tokyo train stations, chatting on mobile phones, listening with disc-player earphones, and flicking "smart cards" instead of stopping to pull out tickets.

Although the technology is generally a novelty elsewhere, gadget-loving Japanese commuters have embraced the cards -- plastic embedded with a tiny computer chip, permitting payments without the hassle of coins or making change.

Here, the challenge is not getting people to use them, but figuring out how to expand the system for shopping, concert tickets and other uses.