Japanese and Chinese are not related

 As much as different languages are influenced by others, Japanese and Chinese aren’t related in any way. Japanese is not related directly to any other language but the writing systems are similar but not the same.

Japanese and Chinese use Chinese characters, although the Japanese system changes phonetics. Also, while Chinese characters are used exclusively in China, the Japanese also use two syllabaries: hiragana (ひらがな) and katakana (カタカナ).