Just east of Kyoto is a great blue lake, which seen from the mountains resembles the biwa or Japanese lute. This is Lake Biwa, the largest lake in Japan, from where Kyoto gets most of its water. Its shores are lined with beaches, resorts, nature parks, hot springs, temples, shrines, and castles. But legend says that in the mud of the lake’s deep, dark bottom sleeps a gigantic catfish, pinned there by a stone placed on its head by the god Kashima Daimyojin.
The giant catfish is called O-namazu, and the reason Kashima had to put a stone on its head was to imprison it there; for when this fish awakes and wriggles free, it causes an earthquake. Catfish have been so associated with quakes in Japanese folklore that Toyotomi Hideyoshi, the unifier of Japan, once wrote to his officers in Kyoto ordering them to “effect all possible anti-catfish-triggered-event measures” while building his castle of Fushimi-Momoyama.
This belief in O-namazu seems to have originated in the Lake Biwa area, as some scholars believe the imagery of Kashima’s stone pinning down the monster shows the stone to have the outline of Chikubushima, the largest island on Lake Biwa and long a sacred site (Gregory Smits, Conduits of Power: What the Origins of Japan’s Earthquake Catfish Reveal about Religious Geography).
When another O-namazu was thought to have caused the quake in Edo (now Tokyo) in 1855, the capital’s ukiyo-e artists turned out reams of prints with catfish themes. Some showed the fish as an angry monster to be feared; others in mockery showed the fish being beaten up by angry townsfolk, or being made to apologize for the destruction it had caused; some show townsfolk partying with the fish and getting it drunk on sake*; some had Kashima overpowering the fish, which supposedly brought protection against future quakes; and in another the fish is being beaten up by geisha, but it’s grinning from gill to gill at being surrounded by so many pretty geisha!
Even the famous haiku poet Matsuo Basho couldn’t resist having fun with O-namazu. In a renga (linked verse) from the Edo Sangin collection, he exchanges lines with his student Jishun thus:
Jishun: “The earth shakes/ A dragon rises into the sky!”
Basho: “No, it’s just a ten-jo catfish.” (1 jo = 1.6 meters)
The connection of catfish to earthquakes may be more than just an old wives’ tale though. Japan has many stories of catfish behaving oddly just before a quake occurs. In 1923, just a few days before that year’s disastrous earthquake at Tokyo catfish were seen splashing agitatedly at the surface of Mukojima Pond, and in Kugenuma in Kanagawa Prefecture they rose to the surface in such droves that folk were quickly able to fill buckets with catfish. Now remember that catfish are bottom dwellers — a pond could be full of them but you’d see no evidence of it. Splashing at the surface in droves is definitely not normal for this fish.
Studies of the Lake Biwa catfish (Silurus biwaensis) seem to show that it is indeed sensitive to seismic activity, becoming much more active and agitated just before a tremor. As early as 1932, Professor Hatai Shinshiki reported that when catfish in his Tohoku University lab swam in a certain way, an earthquake would occur within 12 hours. Perhaps someday Japan will be predicting earthquakes with aquariums full of catfish.
As for an actual daikaiju-size O-namazu living in Lake Biwa, don’t worry. Kyoto hasn’t had a major earthquake in quite a while, making it likely that Godzilla ate it on his last visit.
*The townsfolk partying with O-namazu was a satire on those who looked to profit from the rebuilding after the quake. Many of the namazu-e prints were satirical, digging at either the merchants and tradesmen profiteering from the quake, or at the Shogunate, which was seen as corrupt and ineffective. The military government was so upset with the catfish prints that they banned them!