Ikuchi

Region/Culture: East Asia
Mythos: Japanese Mythology
Primary Type/Nature: Monsters and Beasts
Mythical Attributes: An immense, narrow sea serpent whose slow passage over a ship sheds a flood of gummy oil heavy enough to sink the vessel.
Role in Mythos: A nocturnal maritime hazard of the seas off eastern and western Japan, endured rather than fought.
Relation to Humans: The ikuchi does not bite, seize, or drag sailors under; it threatens only by draping its endless body across a boat and drowning it in shed oil. Crews survive by bailing the slime overboard through the whole slow crossing until the creature finishes passing and slides back into the deep.

The lantern at the stern threw a small circle of light on black water, and for a long while there was nothing to see but that. Then the sea to starboard lifted. Not a wave. Something long and pale broke the surface and kept coming, sliding up over the gunwale with a wet, deliberate weight, and the men understood that they would not sleep that night.

The ikuchi belongs to the night seas off eastern Japan, first set down in the anecdote collections of the Edo period. Sailors working the deep water off Hitachi Province, the coast of what is now Ibaraki, told of an immense fish that showed itself only after dark. It did not rush the boat. It draped itself across the hull and began the slow business of passing over, one endless length of body dragging itself from one side to the other while the crew waited and worked and hoped for the far end of it to appear.

Length was the whole of its horror. The old accounts reckon it at several hundred jō, which is to say thousands of feet, a body so long that hauling all of it across a single ship could take an hour or two, and in the worst tellings two or three days. It was not thick. A thing that size might be expected to have the girth of a temple pillar, but the ikuchi was narrow, more eel than dragon, ribboning over the deck in a line that seemed to have no beginning and no end. In the dark you saw only the part crossing your boat. The rest was out in the water, unseen, still arriving.

What it left behind was oil. As the ikuchi moved it shed a slick, gummy fluid with the consistency of funori, the gluey paste the coast people boiled out of seaweed. It pooled on the planking and ran into the bilge, and it came faster than any single man could manage. The deck grew too slippery to stand on, so that walking fore to aft became a matter of crawling. And the oil was heavy, heavy enough that if it were allowed to gather the ship would settle lower and lower until the sea came in over the side. So the sailors bailed. Through the whole crossing of the monster they scooped and flung the slime back into the water, working in the dark against a weight whose source they could not see, because the alternative was to founder under a hold full of grease.

Survive the night and the danger passed with the dawn. The creature finished its crossing, slid back into the deep, and left behind a boat that had to be scrubbed from stem to stern before it was fit to sail again. No one was bitten. No one was dragged under. The ikuchi killed, when it killed at all, by patience and sheer tonnage of grease, and a crew that kept its nerve and kept bailing came through with nothing worse than aching arms and a ruined night.

The stories do not entirely agree on what it was. Tsumura Sōan, writing in Tankai in 1795, called it plainly a fish, ikuchi, of the waters off Hitachi. Negishi Yasumori recorded a close cousin under the name ikuji, said to haunt the western and southern seas, eel-colored and immeasurable, that snagged on the bow of a ship and hung there squirming for days. Negishi passed on a stranger note as well, from an informant on the island of Hachijō. There, he was told, small ikuji could be found that looked like eels but had no eyes and no mouth and curled themselves into loops, and he wondered whether the great bow-clinging creature was really one of these, ringed around the prow and turning slowly in place. The phrase ikuji naki, lacking backbone or courage, was said to trace back to the beast, though how a monster this alarming lent its name to cowardice is a puzzle the old writers leave alone.

It owes much of its later fame to a picture. When Toriyama Sekien drew a vast sea serpent looping over a ship in his eighteenth-century bestiary, he labeled it ayakashi, and the name stuck fast to the ikuchi even though ayakashi was really a catch-all for any strange thing the sea threw up. Commentators have argued since that the two are one beast under different words. Some later readers, looking at Sekien’s coils, decided the long shape crossing the boat was not the animal’s whole body at all but a single reaching limb, and heard in it an echo of the kraken, the tentacled giant of European waters. Ayakashi carried a darker freight of its own, for the word attached to the belief that such apparitions were the souls of the drowned, risen to the surface hoping to pull the living down to keep them company.

Its power was simply its size and its oil, the one making escape impossible and the other threatening to swamp the boat outright. There was no fighting it. A sword did nothing against a body a mile long that was not trying to fight back. But its weakness was written into the same slow nature that made it terrible. The ikuchi had no hunger for men and no malice in it. It only had to be outlasted. Bail hard enough and long enough, keep the deck clear, and the horror passed of its own accord and left you alive. It was a monster you defeated by refusing to give up, which is perhaps why the coward’s want of spine got hung on its name.

Frequently Asked Questions

What is the Ikuchi?

The Ikuchi is a yōkai of the sea-serpent type from Japanese folklore, an enormously long, narrow fish or eel-like creature that appears at night in the waters off Japan. It is recorded in Edo-period anecdote collections and is best known for the slick oil it sheds as it slowly passes over a boat.

Is the Ikuchi dangerous, and does it attack ships?

The Ikuchi is dangerous but not aggressive. It does not bite sailors or smash the boat; instead it drapes its immense body across the vessel and leaves behind so much heavy, gummy oil that the ship can sink under the weight if the crew does nothing.

How did sailors survive an encounter with the Ikuchi?

Sailors survived by bailing the oil overboard continuously until the creature finished passing. Because the Ikuchi could take hours or even days to slither its whole length across a boat, the crew had to keep clearing the slippery slime from the deck the entire time or risk being swamped.

Where does the Ikuchi come from?

The Ikuchi is associated with the deep waters off Hitachi Province, now Ibaraki Prefecture, in eastern Japan, while a closely related creature called the ikuji was reported in the western and southern seas. It was documented in the Edo-period works Tankai (1795) by Tsumura Sōan and Mimibukuro by Negishi Yasumori.

What is the connection between the Ikuchi and the ayakashi?

The artist Toriyama Sekien depicted a giant sea serpent in his bestiary and labeled it ayakashi, and the name became attached to the Ikuchi. Ayakashi is really a general term for mysterious sea phenomena, so commentators treat the Ikuchi as one specific creature that the broader word came to name.