Koka (�b‰ê, Kōka, also commonly pronounced Kōga) is a rural city in Shiga Prefecture, not far from Kyoto. Together with neighboring Iga, Koka can be considered the homeland of the ninja, and it features a couple of ninja-related attractions, which tend to be less touristically developed than those in Iga.

Since early times, Koka's proximity to Kyoto, in addition to its rugged terrain, made it a good hiding location for those seeking shelter, such as losing parties of battles. It was from such independently minded, self-governing families that ninja and their skills developed. The prominence of Iga and Koka ninja rose during the age of the warring states (15th and 16th century) when they were hired as mercenaries by various lords for their specialized skills.

The mountains west of central Koka are also home to the Miho Museum, a unique museum whose interesting structures are blended in with the natural environment.