Japan's Corporate Number vs. Invoice Registration (T) Number
Japan has two different 13-digit numbers for companies, and confusing them is easy. A corporate number (法人番号, hōjin bangō) identifies a corporation. An invoice registration number — usually written as a "T number" — shows that a business has registered under Japan's qualified invoice system. They look similar, and for corporations the digits are the same. What they prove is not.
The corporate number
Every corporation in Japan is assigned a 13-digit corporate number by the National Tax Agency (NTA), which publishes the number together with the company's name and registered address. The number proves that a corporation exists in the register, under that name, at that address — and whether it is still on the register. It says nothing about invoices or tax registration.
The T number
Since 1 October 2023, Japan has run a qualified invoice system. Only businesses that applied and were registered may issue qualified invoices (適格請求書), and buyers generally need a qualified invoice to claim input tax credits. A registered business receives a registration number: the letter "T" followed by 13 digits. For a corporation, those 13 digits are its corporate number. For a sole proprietor, they are a different number that is not a corporate number.
The trap: same digits, different meaning
- Registration is by application. A corporation can have a corporate number and not be invoice-registered.
- A registration can be cancelled or lapse after it was granted.
- A T number printed on an invoice is a claim, not proof. It becomes reliable only when checked against the register.
How to check
Both registers are public. The NTA publishes the corporate number data and the qualified invoice issuer data on its official sites, where anyone can look up a single number by hand. For systems that need this check inside a workflow — vendor onboarding, invoice processing, master-data maintenance — the same two datasets can be queried together over an API: one request with a corporate number or T number returns the company record, the registration status and dates, and the date of the underlying data.
Japan Corporate & Invoice Check API on RapidAPI
Data sources: National Tax Agency corporate number publication data and qualified invoice issuer publication data, used under the Public Data License (v1.0). Results are based on published data and are not an official certification of registration.