The concept of a monstrous animal under the earth as causer of earthquakes is shared by many peoples.
Its Japanese version is that of an enormous catfish (namazu) living under the earth, having its head just under the province of Hitachi where it is kept down by the Kashima god with the help of a pivot stone. The fish is carrying the whole country on its back and arouses earthquakes by any movement of its body.
Namazu gained great popularity in Japan following a major earthquake that struck Edo (modern day Tokyo) on October 2nd, 1855.
Edo (Tokyo) at that time had already a population over one million. A careful estimate is that about 5000 lifes were lost and 14,000 dwellings destroyed, mostly by the ensuing fire. On the Bay of Edo tidal waves swept away entire villages. The namazu-e gained popularity because of this calamity and countless prints of Namazu were put in circulation.
The prints of Namazu picture a monstrous fish which people believe caused the earthquake. The pictures show either namazu as a catfish or disguised as some human being. The fish is pressed down by the Kashima deity by means of a sword or a huge stone, the so-called kaname-ishi or pivot stone.
Kashima pressing pivot stone on Nazamu to control it
Other prints show the fish in combination with human or divine figures which are trying to tame the namazu with the help of a restricted gourd.
In a frequently occurring variation the namazu has the body of a serpent-dragon. Other substitutions for the namazu fish are the whale (kujira) and the thunder or fire god.
Namazu and the thunder deity are feared, but they also bring material wealth. The myth of the catfish became particularly prevalent during the Edo period when economic conditions threatened the lives of poor people.
Namazu was the cause of earthquakes, which, though they caused trouble and grief to all, caused more trouble and grief to the rich—who had more to lose—and might bring relief to the poor, who could escape their harsh lives in the periods of anarchy that followed earthquakes.
The monster-namazu, with Edo in flames on its head and back, here vomits gold and silver pieces.
Namazu thus also represented, at least for the poor (of whom there were many), the yo-naoshi, the renewal of the world, when everything turns topsy-turvy and the poor shall inherit the gold of the rich.
The association of Namazu with wealth and with its wandering over the earth in the absence of the other deities had brought about a parallelism, even an identity, between Namazu and the deity Ebisu, god of fishermen and luck , who also does not heed the call to the kami assembly in Izumo.
Though Namazu often appears in a semihuman form, usually one that predicts, or causes, personal misfortune (in which case one needs to appeal to the Kashima kami to ensure his expulsion), he might, like Ebisu, also provide wealth.
Namazu gives, or at least lends, riches, if one knows how to solicit him, and if one behaves properly: In many places in Japan there are kuramaya (cave storehouses) where one can borrow lacquer bowls or other utensils for use, provided they are returned.
These are the property of a local deity, often identified with Namazu. But woe if the utensils are not returned: The loan process as well as the good that the utensils bring terminates immediately.
The thunder (Takemikazuchi) and earthquake (Namazu) deities are related and often refer to one another as “colleagues,” or members of the same group.
Earthquakes are thus thunder that bides its time under the earth, as can be seen from the eight thunder gods who emerged from the body of the dead Izanami.
In other version of the Namazu myth, Takemikazuchi and Ebisu (one of the gods from the Shichi-Fuku-Jin) are both suppressing a subterranean monster, either an insect, a serpent (-dragon), a fish or a whale. Into this context of mutual relationships belongs the namazu as destroyer and benefactor.
He is a water-god and as earthquake namazu he is a rusugami, a caretaker-god during the absence of the Kashima deity in the 10th month. There is a great ambivalence in the nature of the namazu to the point of absurdity. He is at times a nigimitama, at times an aramitama, a benevolent and a malicious deity.
Another earthquake deity, Nai-no-kami, was worshiped beginning in the seventh century and was later identified with Namazu. During the Meiji period, attempts were made to personify Nai-no-kami as a separate Shinto earthquake deity.
Part of the Namazu myth is the Tokoyo-no-kuni concept, which is the land of the dead, but also of eternal life, eternal youth and wealth. The Everlasting World (tokoyo), paradise or promised land, which in ancient times was thought to be in Hitachi.
Namazu myths also contain relationships between yo-naoshi (new creation of the world) as charm against earthquakes and between the Kashima no kotobure, that is commandments of the Kashima god, said to be issued through a person supernaturally connected with the god and receiving his commands (shinrei).
When Kashima Daimyojin travels to Izumo to attend the annual conference of the gods on the tenth month, Namazu may exploit this absence and cause earthquakes.