Kosaka and Kōsaka are two separate Japanese surnames, distinguished by the length of the vowel in the first syllable of each surname. They are sometimes spelled identically in romanisation due to omission of the macron in the latter surname. Notable people with these surnames include:Daimaou Kosaka , comedian Kenji Kosaka , politician Kitarō Kōsaka , animator and film director Makoto Kosaka , professional baseball player Nao Kosaka (小坂菜緒), idol, model, actress and member of the Japanese girls idol group Hinatazaka46 Kōsaka Masanobu , samurai warrior Riyu Kosaka , member of the Konami-produced J-Pop group BeForU Tadahiro Kosaka , race walker Yuka Kosaka , gravure idol Zentaro Kosaka , politician
