Kishomon

• Japanese: 起請文 (kishoumon)

Kishômon were a type of blood oath regularly sworn by samurai retainers in the Sengoku and Edo periods, swearing fealty to their lord, and inviting the wrath of the gods should they violate the oath. These oaths were not only signed by name, in ink, but also in blood, typically by thumbprint.

Daimyô frequently swore a three-part oath, swearing to obey all shogunal laws strictly, to keep their own house from wickedness, and to serve their lord (i.e. the shogun) diligently. The oath was sealed with blood, and ended with a formulaic statement, common in Edo period oaths, listing deities which would exact retribution against the speaker should he violate the oath. Daimyô required similar oaths of their retainers, in turn.

Kings of the Ryûkyû Kingdom were regularly required to swear such oaths as well, swearing loyalty to the Shimazu clan. Such oaths were sworn by each king in conjunction with his succession, and were sworn anew for each new lord of Satsuma who came to the headship of the Shimazu house; however, rather than actually being sworn on those occasions, these oaths were often delayed for various reasons, sometimes by as much as five or ten years.