Check your own Japanese

Write or paste a Japanese text. This page holds it up against exactly the rules the site itself teaches: 46 things Japanese does not write, 351 spellings that careful writing avoids, 179 verb forms built by the wrong rule and 96 loanwords that are false friends. Each finding comes with the page on which the rule is explained. Everything runs in your browser; the text never leaves your device.

Your text

What it is measured against

Every rule in this checker is on one of these pages — and the same table checks this site’s own Japanese when it is built. A finding without a source would be an assertion; here are the sources, even without you checking anything.

Past and negative of adjectives i-adjectives na-adjectives Too much, easy to, hard to False friends There is: ある and いる This, that and which も: also, too, neither Is not, was and was not Plain and polite style だけ, しか and のみ: only で: where it happens, and with what ね, よ and よね at the end of a sentence は and が: topic and subject を: the object and the path The である style Hiragana Kanji and their readings Katakana Long vowels, small tsu and small ya, yu, yo Okurigana and words written in kana Punctuation, spacing and direction てもいい and てはいけない: may, must not, need not, must てしまう: done for good, or done and regretted Verb forms The ます-form The potential form The volitional form

What this checker can do — and what it cannot

It does not check your Japanese. It checks 672 particular things in it. A text with no findings is not a text without mistakes: tenses, word order, articles and everything there is no rule for here are invisible to this tool. The reverse holds, though: whatever it reports is explained on a page of this site.

Three levels of certainty, and the difference matters. A mistake is a construction this site explicitly rules out — there is nothing to weigh up. A spelling is not a mistake but a choice that has to be kept. 見(み)れる for 見(み)られる is how most people speak, and careful writing still keeps the ら; て下(くだ)さい and 出来(でき)る are in every dictionary, and everyday writing puts them in kana. A Japanese reader understands all of them at once; mixed with the other spelling in one text they look careless. A note is a question rather than a verdict, kept for words that are good Japanese and may still not be what you meant — the loanwords that look like English and are not, such as マンション, which is an ordinary flat and not a mansion.

The choice between は and が, the particles in general, word order, honorific speech and the choice of kanji are left out on purpose. They are among the commonest mistakes of all, and none of them can be recognised from a pattern: 私(わたし)は and 私(わたし)が are both correct, and only the writer knows which was meant. A checker that guesses is wrong often enough that nobody believes it the next time it is right. Each has its own page; here the checker stays silent.

The word list below is information, not a mark. It shows which levels the words of your text sit at in this vocabulary. A text made entirely of A1 words can be very good, and one full of C1 words very bad.