Database: Kôga

Kōga was a region of the province of Ōmi sharing its borders with what was then the province of Iga. The hills surrounding the valley of the Somagawa basin were lined with small fortified wooden castles which served as defenses while providing residences for local samurai. Numbering no fewer than two hundred and thirty, some of these fortified structures were as close as 500 meters to a their neighbors. As in Iga, the region was controlled by minor samurai living among the peasants, the famous jizamurai. Like the Igans, the people of Kōga were shinobi who served the Rokkaku lords before falling under the control of Oda Nobunaga.

Ninjutsu, which means "the techniques of concealment," was widely practiced among the "people of Kōga." With their ability to blend into the natural surroundings they were experts at night raids and surprise kidnappings.

Iga and Kōga had similar political systems and intermarriages between the jizamurai was a means of maintaining close ties. Some even owned land on both sides of the border. This micro-republic was based on an alliance between the local lords, the jizamurai, and the common people, consisting mostly of peasants, and the monks. (3 categories: the jizamurai, the common people and the monks). The township was governed by a family association called the Kōga gunchūsō.

When Nobunaga attacked Iga in 1581 he sought the support of the people of Kōga and they served him out of obligation. Later authors liked to inject a note of hostility between Kōga and lga, but there are no historical records to support this.