Kanazukai
are the orthographic rules for spelling Japanese in kana. All phonographic systems attempt to account accurately the pronunciation in their spellings. However, pronunciation and accents change over time and phonemic distinctions are often lost. Various systems of kanazukai were introduced to deal with the disparity between the written and spoken versions of Japanese.The former mainstream kana usage, or the Kyū-Kanazukai 仮名遣