Mito Kōmon (水戸黄門) is a Japanese jidaigeki or period drama that was on prime-time television from 1969 to 2011, making it the longest-running jidaigeki in Japanese television history. The title character is the historic Tokugawa Mitsukuni, former vice-shōgun and retired second daimyō of the Mito Domain. In the guise of Mitsuemon, a retired crepe merchant from Echigo, he roams Japan with two samurai retainers, fun-loving Sasaki Sukesaburō (Suke-san) and studious Atsumi Kakunoshin (Kaku-san). An episode typically starts with some injustice perpetrated by a corrupt official, a wealthy merchant or a gangster. The travelers arrive incognito, discover the injustice and quietly investigate it. The episode concludes with a brawl in which the unarmed, disguised protagonists defeat a crowd of samurai and gangsters, culminating in the presentation of the inrō that reveals the hero's identity. Afterwards, the hero passes judgement on the villains, sets things straight with comments and encouragement, and then continues with his journey.

Jidaigeki is a genre of film, television, video game, and theatre in Japan. Literally meaning "period dramas", it refers to stories that take place before the Meiji Restoration of 1868.