Family name origins & meanings
- Japanese : ‘old river’; variously written, with one ancient variant of imperial descent pronounced Kuga; other alternate readings are Furukawa or Kogawa and are derived from a village named Koga in Shimōsa (now Chiba prefecture). The most common Koga name is mostly found in Kyūshū, and is descended from the Takeda family. The name is also found in the Ryūkyū Islands.