Japanese area code
The five-digit standard statistical area code for a Japanese prefecture or municipality, preceding the government-code check digit.
The standard area codes for statistics were established in 1970 and are revised at every municipal merger. They provide a shared geographic reference for Japanese statistical publications.
Five digits: two for the prefecture, from 01 Hokkaido to 47 Okinawa, and three for the municipality within it. A prefecture takes 000 in the last three, so Aichi is 23000, while Abashiri in Hokkaido is 01211. The leading zero is part of the code for prefectures 01 through 09.
The last three digits are unique only inside their prefecture, so only the full five identify a place nationally. Codes are retired and never reused. A municipality that is merely renamed keeps its code, but a town that becomes a city is given a new one, so a changed code does not always mean a changed place.
The Japanese government code is this code with a check digit appended.