The system was initially trialled in parts of Kyushu, and has now been introduced in the rest of Kyushu, Shikoku, Western and Northern Honshu and Hokkaido. The plan is to roll it out to the whole of Japan by July. The “Taspo” card is a contactless “smart-card”, which can also optionally be loaded up with cash for use when buying cigarettes. To get a “Taspo” card, you have to register by producing relevant documentary evidence of identity: name, address, and date of birth (minimum smoking age in Japan is 20). Note that only documents issued in Japan are valid for this purpose. So foreign residents with valid residency or registration documentation will be able to get one, but, from my understanding, tourists and others on short-term visas who have not registered will not. So they'll presumably just have to go into the shop to buy their cigarettes from now on.
As a non-smoker, I'm not affected by this at all. But I thought it a very Japanese solution to the problem of under-age smoking, rather than just getting rid if the machines – there haven't been cigarette vending machines in the UK for a very long time (although this Japan Times article mentions that the same solution to the problem has also been introduced in Germany) - so I thought it worth mentioning here. Full details on the system, registration process, and how to use the cards, can be found here.