Historical Document Collection of Hikone Castle Museum

The Ii family archive at Hikone Castle Museum holds approximately 27,800 documents, designated collectively as an Important Cultural Property. The collection spans the Azuchi-Momoyama through Edo periods and includes letters from Toyotomi Hideyoshi and multiple Tokugawa shoguns, as well as detailed maps of the castle and castle town. Records reveal how individual Ii lords related to the shogunate, how samurai life operated within the castle town, and how the domain functioned in its final decades before the Tokugawa government fell. The collection remains one of the most substantial primary source archives for the study of feudal Japanese administration.