Choosing a company name in Japan involves more than branding. The Commercial Registration Act (商業登記法) and Companies Act (会社法) define specific rules that your name must satisfy before the Legal Affairs Bureau will accept your registration.
The traditional way to check is to visit the Legal Affairs Bureau and search their records, or use the online corporate registration information service. But these methods only check for existing registrations — they do not validate your name against the full set of naming rules.
MmowW's Name Availability Checker does both: it validates compliance with naming rules and helps you identify potential conflicts.
The tool is free, works in English, and gives you results in seconds — no appointment at the Legal Affairs Bureau required.
Type your company name exactly as you intend to register it. Include the entity designation (株式会社 or 合同会社) in the position you prefer — before or after the company name.
Choose KK or GK. The tool verifies that the correct entity designation is present and properly positioned.
The tool checks every character in your name against the permitted set:
Any character outside this set is flagged with a clear explanation of which rule it violates and what alternatives are available.
The validation happens character by character, so even a single non-compliant character buried in an otherwise valid name is caught immediately.
The tool screens for:
If issues are found, modify your name and run the check again. The tool provides specific guidance on what needs to change.
E-commerce company with a stylized name: "ShōpNow 合同会社" — the checker flags the macron over the "o" (ō) as a non-standard character. Standard romaji without diacritical marks is required. The founder switches to "ShopNow 合同会社" and passes the check.
Design studio with a symbol in the name: "A+B Design 株式会社" — the checker flags the plus sign (+) as not included in the permitted symbol set. The founder changes to "A and B Design 株式会社" using permitted characters.
Joint venture with bilingual name: "日本テック株式会社 (Japan Tech)" — the checker confirms that the Japanese portion is fully compliant. The parenthetical English portion is noted as supplementary and may or may not be included in the official registration depending on how it is submitted.
Use our free tool to check your compliance instantly.
Try it free →Q: Can I register the same company name as an existing company?
A: Yes, if the registered addresses are different. The Commercial Registration Act prohibits identical names at identical addresses, but does not require nationwide name uniqueness. However, using a name very similar to an established company could create liability under the Unfair Competition Prevention Act.
Q: Does the tool check for trademark conflicts?
A: The tool checks for naming rule compliance — character restrictions, entity suffixes, and prohibited terms. Trademark conflicts fall under the Trademark Act and require a separate trademark search. The tool notes this distinction and recommends a separate trademark search for comprehensive protection.
Q: Can my company name be in English only, with no Japanese characters?
A: Yes. A company name can be entirely in romaji plus the entity designation. For example, "MmowW合同会社" or "合同会社MmowW" are both valid registrations.
Use the Name Availability Checker at the very beginning of your formation process — before you design business cards, order company seals, or tell anyone your company name. Discovering a naming issue early costs nothing. Discovering it after filing costs time, money, and momentum.
Validate your company name against every naming rule:
Use the Company Name Availability Checker →
Name validated. Next: draft your articles of incorporation with that name officially set. MmowW Scribe walks you through every clause.
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