Kōsa-jinja, Shinto shrine in Japan

Kōsa-jinja is a Shinto shrine in the town of Kōsa, Kumamoto Prefecture, Japan. It consists of several wooden buildings set along a stone path, surrounded by tall trees that shade the grounds.

The shrine has been part of the Kōsa community for several centuries, serving as a gathering point for festivals and ritual celebrations. Some of its buildings have been rebuilt over time, but the site itself has remained in continuous use.

At the entrance, a stone basin is used to rinse the hands before stepping further into the grounds. Wooden plaques with handwritten wishes hang from a rack near the main hall, a common sight at shrines across Japan.

Kōsa-jinja stands in Kōsa, Kumamoto Prefecture, and is counted with Aso-jinja, Kōnoura-jinja and Kengun-jinja as one of the four Aso shrines. The shrine is dedicated to Yaimimitama-no-Mikoto, a son of Takeiwatatsu-no-Mikoto, with Takeiwatatsu-no-Mikoto, Kamachi-hime-no-Mikoto, Kamuyamato-iwarehiko-no-Mikoto and Himetataraisuzu-hime-no-Mikoto also enshrined here. It held the rank of a gōsha, a district shrine, and served as the second shrine of Higo Province.

The shrine was originally called Kaburazaki-gū; it was renamed Kōsa after Empress Jingū reportedly deposited her armour here following a military campaign. It is one of the Aso Four Shrines, alongside Aso, Kōnōura and Kengun, and served as the second-ranked shrine of Higo Province.