Please do not mix full-width and half-width characters.
このフォームは全角カタカナで入力してください。
Please fill in this form using full-width katakana.
full-width kana
full-width digit
full-width character
full-width katakana
full-width space; em space
full-width Roman character
Compound of 全 (zen, 'full') and 角 (kaku, 'square' or 'block'), referring to the square shape of a full-width character cell in traditional Japanese typesetting.