Japan T-Number (Invoice Seido) Validator
Validate the authenticity, format, and checksum of Japan T-Number (Invoice Seido).
About Japan T-Number (Invoice Seido) Validation
The T-Number is the mandatory identifier established by Japan's National Tax Agency (NTA / 国税庁) under the Qualified Invoice System (Invoice Seido / インボイス制度). Only invoices with a valid registered T-Number qualify buyers for Japanese Consumption Tax (JCT) input tax credits.
The format consists of uppercase `T` followed by 13 digits (`T1234567890123`). For corporations, the 13 digits match the corporate Houjin Bangou, where the leading digit is the Modulo 9 checksum of the remaining 12 digits.
Anatomy & Structure of the T-Number (Invoice System Registration)
The Japanese Qualified Invoice T-Number consists of 2 parts:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 | Tax Prefix | 1 char | Fixed letter 'T' (Tax/Invoice System) | T |
| 2 to 14 | Corporate/Registration Number | 13 digits | For corporations, matches the 13-digit Corporate Number with Modulo 9 check | 5123456789012 |
Japan Invoice System Validation (インボイス制度)
Official compliance rules under the Consumption Tax Act:
Prefix 'T' + Corporate Number Modulo 9 Verification
- 1. Verify mandatory uppercase prefix 'T'.
- 2. Strip prefix 'T' and extract the remaining 13 digits.
- 3. For corporate entities, validate Modulo 9 checksum on the leading digit.
- 4. For registered sole proprietors, validate exact 13-digit numeric structure.