''Ikuchi'' is a yōkai of the

sea serpent A sea serpent or sea dragon is a type of dragon sea monster described in various mythologies, most notably Mesopotamian (Tiamat), Judaeo-Christian (Leviathan), Greek (Cetus, Echidna, Hydra, Scylla), and Norse (Jörmungandr). Mythology and folk ...

type in Japanese legend. It has been described in a two anecdotes collections during the

Edo period The or is the period between 1603 and 1867 in the history of Japan, when Japan was under the rule of the Tokugawa shogunate and the country's 300 regional '' daimyo''. Emerging from the chaos of the Sengoku period, the Edo period was characteriz ...

, namely (1795) by and (completed 1814) by .

''Tankai''

According to ''Tankai'' ("Sea of Stories", 1795) by , the is an extremely long

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

dwelling in the deep waters off Hitachi Province (now

Ibaraki Prefecture is a Prefectures of Japan, prefecture of Japan located in the Kantō region of Honshu. Ibaraki Prefecture has a population of 2,871,199 (1 June 2019) and has a geographic area of . Ibaraki Prefecture borders Fukushima Prefecture to the north, ...

). It has only been spotted at night, sometimes rearing out of water and slinking over a ship, taking a long time to complete its passage, and leaving a residue of viscous oil. The sheer amount of oil needs to be dumped overboard lest the ship may sink. It does not have much thickness supposedly, but spans a total length of several hundred ''jō''（several thousand feet), requiring 1 or 2 (1+ or 2+ hours, perhaps little less than 3 hours) to finish hauling its whole length across the ship. Its body oil is said to have the consistency of ''funori'' (gummy substance derived from '' Gloiopeltis'' seaweed) and slickens the ship's deck so walking back and forth becomes impossible. Thus the ship needs be scrubbed and cleansed thoroughly after a visit by the ''ikuchi''.

''Mimibukuro''

In "Mimibukuro" ("Ear bag", 1782–1814) by , there occurs a description of a similarly named creature called ''ikuji''". This ''ikuji'' was said to appear in the western and southern seas of Japan, and it would get snagged on the bow of the ship. It had the colors similar to an

eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...

, and was immeasurably long, perhaps several ''jō'' in length, and it would keep squirming on the bow for the length of 2, 3 days. The phrase "''ikuji naki''" ("lacking courage") purportedly derives from this creature's name. The author, Negishi, states that he heard from a certain informant that in the island of Hachijō-jima in Izu Province (the island is now incorporated into

Tokyo Prefecture Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and List of cities in Japan, largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, ...

), there can be found small-sized ''ikuji'' which look like eels but have no eyes or mouth and form circular loops. Negishi thus conjectures that the (full grown) ''ikuji'' reported to dangle itself from the ship's bow, must actually be hanging like a ring on the bow and revolving around.

Sekien's ''ayakashi''

The drawing of "'' ayakashi''" in Toriyama Sekien's ''

Konjaku Hyakki Shūi is the third book of Japanese artist Toriyama Sekien's ''Gazu Hyakki Yagyō'' tetralogy, published c. 1781. These books are supernatural bestiaries, collections of ghosts, spirits, spooks and monsters, many of which Toriyama based on literature, ...

'' depicts an enormously long sea creature, said to appear in the seas of Western Japan, "slithering" over a ship for two or three days, depositing loads of oil, forcing the crew to "furiously bail" it out, for fear it would cause their ship to sink. The description of Sekien's ''ayakashi'' is closely similar to the ''ikuchi'', and Japanese commentators have equate them, noting that ''ayakashi'' is merely a generic term for all sorts of strange phenomena (and monsters) of the sea.

Analyses

The ''ikuchi'' has depicted by Sekien's like a

and some sources categorize ''ikuchi'' as belonging to a class of sea serpents, or creature of uncertain identity, i.e.,

cryptid Cryptids are animals that cryptozoologists believe may exist somewhere in the wild, but are not believed to exist by mainstream science. Cryptozoology is a pseudoscience, which primarily looks at anecdotal stories, and other claims rejected by ...

s. It has been conjectured it might be unknown giant species of

sea snakes Sea snakes, or coral reef snakes, are elapid snakes that inhabit marine environments for most or all of their lives. They belong to two subfamilies, Hydrophiinae and Laticaudinae. Hydrophiinae also includes Australasian terrestrial snakes, where ...

. English translators of Sekien regard the "long thing" appearing out of the sea, not as the entire body of the sea-serpent like creature, but as a single strand of long "tendril" (tentacle) of the monster, suggesting this may be an imported lore of the

kraken The kraken () is a legendary sea monster of enormous size said to appear off the coasts of Norway. Kraken, the subject of sailors' superstitions and mythos, was first described in the modern age at the turn of the 18th century, in a travelogu ...

, a legendary giant

cephalopod A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...

creature. Am additional piece of lore associated with the ''ayakashi'' is that they are formed by the souls or ghosts of humans who have drowned and want others to join them.

Explanatory notes

References

{{Japanese folklore long Japanese literature Yōkai Legendary fish Sea serpents