I want to sign up to this website that has an English version, but unfortunately, the captcha for it is Japanese. I can't read Japanese and no online translator seems to be able to make sense of the 2nd line. Here it is:

表示されている数式を計算して、半角数字で答えを入力してください: 必須(半角数字)


enter image description here

Why is this an effective captcha?

I'd also like to know the meaning, the translation, and why no translator seems to be able to translate that last word.


  • 1
    It is an effective captcha just because you weren't able to read; they successfully shut out efforts of automatic recognition. Except they forgot to make an English version... Jun 29, 2021 at 6:13

1 Answer 1


It shows ”ろく たす なな“. To obfuscate sentence, It use combination of HIRAGANA and KATAKANA.


  • OK but what does the first line say? Jun 28, 2021 at 23:07
  • 1
    @ConsultingNewb it says "Solve the following arithmetic problem and submit your answer in half-width characters." Jun 29, 2021 at 7:47

Not the answer you're looking for? Browse other questions tagged .