Japanese Grammar Checker
AI-powered grammar checker for Japanese text. Detect and correct particles, keigo (honorifics), spelling, punctuation, and common mistakes instantly.
Suggestions
0 issuesEnter Japanese text and click "Check Grammar" to see suggestions.
Particle Error Detection
Identifies common particle (は, が, に, を, etc.) mistakes and provides corrections.
Keigo (Honorific) Support
Checks for appropriate use of respectful and humble language in formal contexts.
100% Private
Your text is sent securely for checking, but we do not store it. API results are processed in real-time.
Mobile Optimized
Works perfectly on smartphones, tablets, and desktops. Check Japanese grammar anywhere.
What is a Japanese Grammar Checker?
A Japanese grammar checker is an advanced writing tool that automatically detects and corrects grammatical errors, particle misuse, keigo (honorific language) issues, spelling mistakes, and punctuation errors in Japanese text. It uses AI-powered natural language processing to understand context and provide meaningful suggestions for improvement.
Why Use Our Japanese Grammar Checker?
• Particle Correction: Fixes common particle errors (は/が, に/で, を/に, etc.)
• Keigo Assistance: Ensures appropriate honorifics for business and formal writing
• Spelling & Punctuation: Catches typos and punctuation mistakes
• Style Improvements: Suggests more natural and concise phrasing
• Comprehensive: Combines LanguageTool API with powerful local regex rules for maximum error coverage
Common Japanese Grammar Errors
Japanese learners and native speakers alike often make these mistakes:
- Particle confusion: Mixing up は and が, に and で, を and が, etc.
- Verb conjugation errors: Incorrect verb forms (ます, て-form, ない-form).
- Keigo misuse: Using 尊敬語 (sonkeigo) where 謙譲語 (kenjougo) is appropriate, or vice versa.
- Word order: In Japanese, word order is more flexible but can sound unnatural if not typical.
- Redundant expressions: Overuse of です・ます forms or repetition of particles.
- Spelling mistakes: Especially in kanji choice or okurigana.
Who Needs a Japanese Grammar Checker?
Japanese Learners (JLPT candidates)
Students preparing for JLPT N5-N1 benefit from catching errors and learning proper usage. The checker provides explanations that aid study.
Business Professionals
Writing emails, reports, or presentations in Japanese? Ensure your keigo is correct and your message is professional.
Content Creators
Bloggers, writers, and social media managers can produce error-free Japanese content that resonates with native speakers.
Translators and Editors
Quickly check translations for grammatical consistency and natural flow.
Common Japanese Grammar Errors & Corrections
| Error Type | Incorrect Example | Correct Example | Explanation |
|---|---|---|---|
| Particle (は/が) | 私が学生です。 | 私は学生です。 | は indicates the topic, が marks the subject in a neutral statement. |
| Particle (に/で) | 学校で行きます。 | 学校に行きます。 | に indicates destination; で indicates location of action. |
| Keigo (Honorific) | 社長が言いました。 | 社長がおっしゃいました。 | Use おっしゃる (sonkeigo) for the boss's speech. |
| Verb conjugation | 食べないです。 | 食べません。 | Polite negative form is ません, not ないです (though casual). |
| Word order | 明日学校に私は行きます。 | 私は明日学校に行きます。 | Typical order: topic → time → place → verb. |
Why Choose Our Japanese Grammar Checker?
Our tool stands out for its accuracy, ease of use, and privacy:
- Powered by LanguageTool + Local Rules: Uses a proven, open-source grammar engine combined with a comprehensive set of regex‑based rules for Japanese to catch even more errors.
- Real-Time Feedback: Get instant suggestions as you type or after clicking check.
- Comprehensive Error Coverage: Detects particle errors, conjugation issues, keigo misuse, spelling, punctuation, and common mistakes like 日曜き → 日曜日, 良いかった → 良かった, etc.
- Privacy First: Your text is only sent to the LanguageTool API for processing and is not stored. Local rules run entirely in your browser.
- No Limits: Check as much text as you want, completely free.
- Learning Aid: Each suggestion includes an explanation, helping you understand your mistakes.
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Frequently Asked Questions
How accurate is this Japanese grammar checker?
It combines the LanguageTool API with a set of hand‑crafted local regex rules that catch many common errors (particle misuse, verb conjugation, keigo, and spelling). This hybrid approach gives you a thorough check. However, no grammar checker is perfect, so we recommend reviewing suggestions manually.
Does it check keigo (honorific language)?
Yes, both the API and local rules identify inappropriate or missing honorifics and suggest corrections for respectful (sonkeigo) and humble (kenjougo) language.
Is my text private?
Yes. Your text is sent over HTTPS to the LanguageTool API for processing. We do not store or log your text. The API does not retain your text beyond the request. Local rules run entirely in your browser.
Can I use this for JLPT preparation?
Absolutely. It helps you identify and correct errors, making it a valuable study tool for all JLPT levels.
Is there a text length limit?
The LanguageTool API has a limit of about 20,000 characters per request, which is ample for most writing. Our tool handles this automatically.
Does it work with casual Japanese (タメ語)?
Yes, it can detect issues in casual Japanese as well, though its primary strength is in detecting grammatical correctness rather than style.
How do I apply a suggestion?
In the output panel, you'll see highlighted errors. Clicking a suggestion button will replace the error with the corrected text in the input area automatically.
Does it work on mobile?
Yes, the interface is fully responsive and works on smartphones and tablets.
Is this tool free?
Yes, completely free to use with no limits.
What if the API is down?
We provide a fallback message indicating the service is temporarily unavailable. Please try again later.