When only part of the address is filled in
Most postcodes settle the prefecture, the city and the district. Some settle less. The plugin then fills in only what is certain, instead of guessing.
Postcodes shared by several places
| The postcode covers | What is filled in |
|---|---|
| Several districts of one city | The prefecture and the city. The customer types the district. |
| Two cities | The prefecture. The customer types the city and the district. |
| Two prefectures | Nothing. Only a handful of postcodes on prefecture borders are like this. |
| A whole village or town that has no districts | The prefecture and the city. The address continues with the lot number. |
Postcodes of large businesses
A postcode that Japan Post assigns to one business fills in that business’s street and number as well, for example 永田町１丁目６－１ for the postcode 100-8914.
Buildings with their own postcodes
Some tall buildings have a postcode for each floor. The address line then gets the district, the building’s name and the floor, as Japan Post lists them.
Notes in Japan Post’s data
Japan Post adds notes to some district names, such as the range of block numbers a postcode covers. The plugin leaves these notes out, so only the district name is filled in.