A system of writing in Japanese that specifies the usage and distinctions of hiragana and katakana characters based on pronunciation and grammatical context, reflecting the linguistic norms of different historical periods.

The conventions and standards employed in the representation of Japanese sounds through kana, including guidelines for the differentiation of homophones and the appropriate placement of characters within words and sentences.

The practice of writing the Japanese language with kana, encompassing both historical and modern methods, which varies in terms of phonetic representation and stylistic choices throughout different eras.