Japan Address Generator

Native order versus romanized order

In Japanese, an address is written from the largest unit to the smallest: the postal mark and code (〒150-0001), then the prefecture (Tokyo-to, Osaka-fu, Kanagawa-ken), the city or ward, the district (machi or chō), the block numbers and finally the building name and room. The recipient’s name comes last. When the same address is written in Latin script for international mail, the order is reversed so it reads like a Western address: building and room, block numbers and district, ward and city, prefecture with the postcode, and JAPAN.

This generator uses the romanized order, for example Green Court 302 / 2-14-7 Jingumae / Shibuya-ku, Tokyo 150-0001. If your product is used in Japan, the form itself should follow the native order, because Japanese users type the postcode first and expect the rest to be filled in.

Block numbers instead of street names

Most Japanese streets have no names. A location is described by numbered areas: the chōme (丁目, a subdivision of the district), the banchi (番地, a block) and the gō (号, a building on that block). Written together they become 2-14-7. Some rural addresses only have a banchi, such as 1234 Ōaza.

Two big cities have their own systems. In Kyoto, central addresses often describe a route along named streets with words meaning “go north” or “go south” (agaru, sagaru). Sapporo uses a grid of jō and chōme (Kita 3-jō Nishi 4-chōme). The generator only produces the common chōme-ban-gō style, so add those formats to your own tests if you serve those cities.

Postcode structure

Japanese postcodes have seven digits written NNN-NNNN. They replaced the older three- and five-digit codes in 1998. The first three digits identify a broad delivery area (codes from 100 to 208 belong to Tokyo, 530 is Osaka’s Kita ward), and the last four usually point to a single district or even one large building. Hokkaido codes start with 0, so a code stored as an integer loses its first digit.

Japan Post publishes the full list of codes as a free downloadable file (the “KEN_ALL” CSV), and most Japanese checkouts use it to fill in the prefecture, city and district automatically. The generator picks codes in the right range for each ward, but the last digits are random and may not exist in that list.

Form and encoding pitfalls

• Accept both half-width digits (1-2-3) and full-width ones (１－２－３), and normalise them before validation.
• Offer the 47 prefectures as a select, in the official order from Hokkaido (01) to Okinawa (47).
• Leave room for long building names and a separate room number field.
• Japanese forms usually ask for the name in kanji and its reading in katakana (furigana); plan separate fields if you localise.
• Validate the postcode with ^\d{3}-?\d{4}$ and store it as text.

Names in the test data

Japanese names are written family name first in Japanese. The name generator follows that order and uses romanized spellings without long-vowel marks (Sato rather than Satō), which is how most Latin-script forms receive them. This tool does not generate My Number or any other identifier.

Prefectures of Japan

The generator uses the 47 first-level prefectures below, with the codes used in addresses. Cities are picked from 18 places spread across the country, each with postcodes from its own range.

Example Japan test addresses

Validation pattern used for the Postal code (〒): ^\d{3}-\d{4}$. It checks the format only — whether a code is actually in use is known only to the postal operator.

Phone numbers in Japan test data

Japanese numbers are written +81 without the leading 0; mobiles use 070, 080 or 090 domestically (090-XXXX-XXXX). We know of no officially reserved fictional range for Japan, so the generator leaves the phone field blank instead of producing numbers that might be in service.

Sources

• Japan Post – postal code search and data
• Wikipedia – Postal codes in Japan
• Wikipedia – Japanese addressing system
• ISO 3166-2:JP (Wikipedia)

Postcode ranges, region lists and address conventions checked against these sources in October 2026. Street names in the generator are synthetic.

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