The Shimōsa (しもうさ) is an all-stations train service in Japan operated by the East Japan Railway Company (JR East) between Kaihimmakuhari in Chiba Prefecture and Ōmiya in Saitama Prefecture. Shimosa looks like Musashino train, but Musashino train goes from Hachioji or Fuchu-hommachi and Shimosa goes from Shin-Narashino or Kaihimmakuhari.