Namazu-e woodblock prints became popular soon after the Great Ansei Earthquake struck the city of Edo (now known as Tokyo) in November 1855. According to popular Japanese belief at that time, earthquakes were caused by giant catfish (namazu) thrashing about in their underground lairs. By possessing a namazu-e woodblock print, one might be afforded protection from future earthquakes.
Within weeks after the Great Ansei Earthquake, the popularity of namazu-e increased dramatically, with as many as 400 different types available. The massive earthquake had killed 7,000 people and inflicted widespread damage. Survivors were clamoring for a means to assuage their fears. Unfortunately two months later, the Tokugawa government, which maintained a strict system of censorship over the publishing industry, prohibited the production of these prints. Today only a handful of namazu-e prints have survived.