Japan Mailing Address Formats and Other International Mailing Information

When mailing an envelope or postcard, leave at least the bottom 16 millimeters (5/8 inch) blank on both front and back. (The postal service's reading and sorting machines might need this space to print bar codes on your mail.)

Address Format Information

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Postal Information for Japan from japan-guide.com

Nice; includes additional links.

sci.lang.japan FAQ section 13.3. "How does the Japanese addressing system work?"

 

Japanorama: Japanese Address Formats

Has some good examples, but postal code format shown is the old three digit instead of the new longer format.
Also, be sure to write 'Japan' on a line below the rest of the address when you mail from the United States or other Western countries to Japan.

Bruce "Tog" Tognazzini's perspective on the Japanese address system

"How to write Japanese address" ("Wayback Machine" copy)

Sometimes slow to download, but good. Includes information about latest postal code change. (Link is to a "Wayback Machine" copy because original page was recently taken down.)

Google ad(s) are sometimes shown above.

Postcode Search (find Japan postcodes / postal codes = 'Japanese zip codes')

Postcode finder (not in English)

Postal Rates to or from Japan

Postage calculators and tables showing how much postage you need to mail or ship to and/or from Japan are at the International Postal Rates Page.

Finding Out Addresses (such as addresses in Japan / Japan address search)

See Finding An International Address / Address Search.