The Japanese Postal customer barcode is Japan Post's 4-state barcode. It carries the 7-digit postcode and the numbers of the address, so mail can be sorted down to the building.

What it holds
Characters	Digits, hyphens and capital letters; lowercase is turned into capitals. Typically the postcode, then the address numbers separated by hyphens.
Length	The barcode has 20 positions: a digit or a hyphen takes one, a letter two.
Check digit	A check character, worked out by Labeljoy and added to the bars. It isn't shown in the readable text.
Readable text	The value, under or over the bars.

The rest of the settings - text position, quiet zone, color - are in the Barcode section.

What goes wrong
Invalid characters in input data.	The value has something other than digits, hyphens and letters A to Z.
Input data too long.	The value needs more than the 20 positions - remember that a letter takes two.