The 1855 Ansei Edo earthquake; also known as the Great Ansei Earthquake; was one of the major disasters of the late-Edo period. The earthquake occurred at 22:00 local time on 11 November. It had an epicenter close to Edo (now Tokyo); causing considerable damage in the Kanto region from the shaking and subsequent fires; with a death toll of about 7;000 people. The earthquake also triggered a tsunami. Within days; a new type of color woodblock print known as namazu-e (lit. 'catfish pictures') became popular among the residents of the shaken city. These prints featured depictions of mythical giant catfish (namazu) who; according to popular legend; caused earthquakes and related tsunami by thrashing about in their underground lairs. In addition to providing humor and social commentary; many prints claimed to offer protection as talismans from future earthquakes.

The popularity of namazu-e exploded; and as many as four hundred different types became available. The phenomenon ended two months later when the Tokugawa government; which maintained a strict system of censorship over the publishing industry; forbade production. Only a handful are known to survive today.