someone may have already made this point but I didn't see it scanning through the comments: Japan has long had a paper-based family registration ("koseki") system. births, deaths, marriages, current address are all recorded in a file (ofetn one sheet of paper) at the city offices where the head-of-family lives. Marriages transfer one person from one family register to another. New heads of household are established as generations become independent, but can be tracked way way back. So the government already has an awful lot of this nformation already correlated and accessible in local offices; the new system sounds like it's pulling all that together into a national DB so they can get the info without calling the local office and having someone read it out over the phone.