Yokai Encyclopedia

This version looks at Hyōsube as a distinctly Kyushu kind of kappa, one tightly bound to the taboos of the home. Where most kappa tales unfold at rivers and deep pools, Hyōsube's stories push indoors—into the bathroom, the bathhouse, and the stable. The water a hairy Hyōsube has used is held to be defiled, fouled with floating hair; a horse that touches it collapses, and anyone who drains the water without leave is cursed and loses his horse. Stories of this kind are told all across the region. When to drain the bath, who may use it—such admonitions about the manners of everyday life were voiced in the form of Hyōsube's curse. In the fields it is said to love and ravage eggplant, and people offered the first of the crop to keep it content. Its birdlike cry of "hyō-hyō" is said to be the very origin of its name. The hairy, bald-crowned, comical figure drawn in the Edo-period Hyakkai Zukan and Gazu Hyakki Yagyō conveys less a thing of terror than a familiar creature living right beside human life.

An interpretation based on Toriyama Sekien’s Hyakki Tsurezure Bukuro and related Hyakki Yagyō iconography. Gourds served as containers for water or sake and as percussion in festivals, and after long use were believed to acquire spirit in line with the tsukumogami view. The Gourd Boy appears as a human figure with a gourd for a head, briefly emerging from a night path or from grass to make passersby flinch, and little more. Its nature, name, and any definite harm are not fixed in sources, and alongside utensil-yokai like the Mortar Monk it is read as an allegorical old tool given life. Local oral lore is scant, with paintings and later commentaries as the main sources.

In the imperial court’s Great Tsuina exorcism, this figure confronts and drives out pestilential oni. Wearing a four-eyed square mask, bear hide, and armed with a halberd and great shield, he leads pages and tsuina attendants to circuit the four directions of the palace. The rite follows set forms—onmyoji invocations, drum cues, and expulsion beyond the gates—and later influenced demon-chasing observances at temples and shrines. By the late Heian period, shifts in the term tsuina saw him at times enact a visible “oni role.” Though attire, implements, and routes changed with ceremonial norms, the core purpose remained the banishment of epidemics and ill fortune.

An interpretation shaped by medieval war tales, otogizōshi storybooks, and early modern theater. As Shuten-dōji’s foremost lieutenant, Ibaraki-dōji held Mount Ōe and was routed by Raikō’s ruse. Later tales tell of Watanabe no Tsuna cutting off and reclaiming an arm at Ichijō Modoribashi or at Rashōmon. Accounts vary on birthplace and even gender, with traces in Settsu and Echigo traditions. This version follows the most widely circulated storyline in the sources and avoids embellishment.

The heart of Ichikishima-hime's identity lies in the idea of the 'princess of the sacred island': a goddess who dwells in the island where divine service is performed. At Munakata on the Genkai Sea, she protects routes toward the continent; at Itsukushima in Aki, she watches over the passages of the Seto Inland Sea. The divine command concerning the northern sea route makes her a guardian of the boundary joining the realm to the ocean. Her historical identification with Benzaiten layered the virtues of water, wealth, music and performance, beauty, and wisdom upon this maritime guardianship. Itsukushima Shrine's halls over the water and great vermilion gate provide its most majestic expression. At high tide the sanctuary seems to float; at low tide it reconnects with the land. The changing waterline continually redraws the boundary between sea and shore, sacred precinct and human world—the very boundary she guards. Ichikishima-hime remains inseparable in lineage from her sister goddesses Tagori-hime and Tagitsu-hime, and historically cannot be understood without Benzaiten, the deity with whom she was joined. Ebisu, another deity of the sea and good fortune, echoes parts of her religious role. She is therefore more than a local goddess of Miyajima: her worship spans the Genkai Sea and Seto Inland Sea and brings safe navigation into relation with cultural and material flourishing.

A wind god enshrined at Ichimokuren Shrine on Mount Tado, who raises sudden gales over Ise, Owari, Mino, and Hida. The Wakan Sansai Zue records that the wind uproots trees, topples rocks, and wrecks houses, yet blows along a single path and harms nothing else. The shrine's deity, Ame-no-Mahitotsu, is a smith god who forged blades, axes, and iron bells; at Tado he rules the weather with his father and has received prayers for rain and for safety at sea in Ise Bay. Because the god is said to leave his shrine when he rages, the sanctuary has no doors.

To read Iizuna Saburō, one must overlay three strata: the syncretic honzon-image of "Izuna Gongen," the heterodox art of the "Izuna method," and the devotion of the Warring-States commanders. The antiquity of this faith is backed by the texts. The Asabashō of the first year of Kenji (1275) carries the name of Mt. Iizuna and its founding ascetic; the Togakushi-san Kenkō-ji Ruki (1458) records "Izuna Saburō" and "the third tengu of Japan"; the Iizuna-san Meguri Saimon (1546) gives the origin as the Chira Tengu come from Tenjiku; and the Iizuna-san Ryaku Engi transmits the honji-butsu and the lineage of the Sennichi-dayū. From Kamakura to Edo, it is a faith handed down in layers. The iconography of the honzon is profoundly distinctive. A crow-tengu holding a sword and a rope rides upon a white fox, with a snake often coiling about the fox. Its honji-butsu is expounded now as Fudō Myōō, now as Dakini-ten, varying by source. It is precisely this composite character—"tengu, fox, Fudō and Dakini" joined in a single body—that is the reason Izuna Gongen, surpassing a mere mountain tengu, became a point of concentration of esoteric ritual power. At Takaosan Yakuō-in, the Iizuna Shrine of Shinshū, Jinya-ji on Mt. Kano in Chiba and elsewhere, the faith is especially deep in Kantō and to the north. The "Izuna method" is the practical face of this ritual power. This sorcery, which employs tengu and kuda-gitsune to heal illness and, by possession, to deliver oracles, was counted a heterodox art alongside the Atago Shōgun-hō and the Dakini-ten-hō, and those who wielded it were called Izuna-tsukai. The folk belief that one kept and employed kuda-gitsune within a bamboo tube made the very name "Izuna" a byword for witchcraft. And it was the devotion of the warrior houses that raised Iizuna Saburō to a war-god. It is famous that the crest of Uesugi Kenshin's helmet was an image of Izuna Gongen; there is also the case of Takeda Katsuyori granting the name Nishina to the adopted son of the Sennichi-dayū, and commanders such as Hosokawa Masamoto who practiced the Izuna method itself. As a god who governs victory in war, Iizuna Saburō is, even among the forty-eight tengu of the Tengu-kyō, the seat most bound to this-worldly benefit. Chigiri Kōsai of tengu scholarship placed this many-sided Iizuna Saburō within the system of the great tengu of the many mountains.

This version follows the figure recorded in the Tenpō-era compendium Hokuetsu Seppu. Its form is ape-like yet larger than a human, with long hair flowing from crown to back, appearing after parting the dwarf bamboo in mountain ravines. It shows no intent to attack homes, chiefly begs for cooked rice, and repays alms by carrying loads and similar deeds. It is closely tied to the weaving culture of Echigo-chijimi, and in tales of loom maidens it intervenes amid household work rules and notions of ritual purity, turning the tide so deadlines are met. Such accounts treat it as a mountain spirit observing human industry and bringing harmony to cycles of trade and production, akin to food offerings made to mountain deities or guest spirits. Later it was reportedly seen at times but returned to the mountains, leaving only its name. Though an unidentified beast, its refusal to harm and habit of repaying kindness place it on the boundary between uncanny and blessed in local lore.

A strand of Okinawan beliefs about living spirits. When hatred or envy swells, a person’s spirit may slip out while retaining their form and afflict the target with illness or malaise. Reports describe several modes: possession via gifts, attachment through a curse-doll known as the Nama-Jama Buddha, and even obsession achieved by will alone. Harm was said to strike not only people but also livestock and fields. Communities responded with yuta prayers, apotropaic fouling, and even driving it off through scolding and insults. Some accounts say the lineage passes matrilineally, leading to recorded cases of avoided marriages. Early modern records note accusations, lawsuits, and punishments for alleged use.

The image of the ikiryō holds two faces: a curse born of resentment, and gentler visitations tied to parting before death or to acts of gratitude. In Heian beliefs, overpowering thought left the body as a “shadow,” appearing at bedchambers, ox-drawn carriages, or gates. In the medieval and early modern eras, scenes witnessed in dreams, will-o’-the-wisps, and flying heads were taken as proof of the soul’s separation. In medical views it was classed as a disorder of the departing soul or of the shadow, with reports of people seeing their own double. The cursing rite of the Hour of the Ox is often linked as a willed sending of intent by the living, though not identical. Regional lore varies in name and form, with some places recording it as a footfall-making human shadow. Overall, it is understood as the coagulation of thought taking shape, a spiritual action of the living set against the dead.

The principal deity of Inari, Ukanomitama-no-Kami (also known as Ukanomitama-no-Mikoto), is a goddess of grain and food appearing in the first volume of the "Kojiki" (712). The name combines "Uka" (ancient word for food) and "Mitama" (spirit), preserving its simple folk origin as the "personification of spiritual power dwelling in grains." The head shrine, Fushimi Inari Taisha (Mount Inari, Kii County, Yamashiro Province; present-day Fushimi Ward, Kyoto), originated on the first Day of the Horse in February 711. It was founded when Hata-no-Irogu, head of the Hata clan (an immigrant clan who pioneered the Kyoto basin and Fushimi area), shot an arrow at a target made of mochi (rice cake). In a miraculous event, the mochi transformed into a white swan, flew away, and sprouted rice plants where it landed on the mountain peak, prompting the enshrinement of three deities (according to a lost text of the "Yamashiro no Kuni Fudoki"). The three deities were Ukanomitama-no-Okami (the main deity), Satahikoo-no-Okami, and Omiyanome-no-Okami; later, Tanaka-no-Okami and Shi-no-Okami were added to collectively form the five Inari Okami. For its rapid expansion in faith after the Heian period, its connection with To-ji Temple, the head temple of Shingon Esoteric Buddhism, played a decisive role. Starting with the legend of Kukai seeking Inari's cooperation when constructing To-ji, Shingon Buddhism and the Inari faith became deeply intertwined, leading to a syncretism with the Indian esoteric female demon Dakini-ten (Ḍākinī). Originally a "man-eating female yaksha," Dakini-ten softened as she passed through Tibet and China to Japan, becoming depicted as a "celestial maiden riding a white fox," and was eventually identified with Inari. This established a unique lineage of Buddhist Inari (Toyokawa Inari/Myogon-ji founded in Aichi in 1441, Saijo Inari/Myokyo-ji founded in Okayama in the 1300s, etc.), coexisting with the Shinto Inari (Fushimi lineage). During the Edo period, a massive boom occurred where people of all classes—samurai, townspeople, and farmers—enshrined Inari in small shrines on their properties as household deities. It became so widespread that a famous senryu poem listed "Iseya, Inari, and dog poop" as the most commonly seen things in Edo. Modern Inari shrines are estimated at about 32,000 (2,900 head shrines + branch shrines + household shrines), making it Japan's largest belief system by number of shrines. The relationship with foxes requires careful attention. While Fushimi Inari Taisha officially clarifies that "the fox is a divine messenger (familiar) of the Inari deity, not the deity itself," in folklore, many regions treat the fox itself as the Inari deity. This "fox deity faith" from the Edo period onward remains the mainstream of folk belief today. The messenger foxes are called "Byakko" (white foxes) and are traditionally depicted holding one of four items in their mouths: a jewel, a key, a rice sheaf, or a scroll. The jewel represents divine virtue, the key opens the spiritual granary, the rice sheaf represents grain, and the scroll signifies Buddhist scriptures. The main prayers are for bountiful harvests, prosperous business, family safety, fire prevention, and warding off epidemics. Especially since the Edo period, as it became a merchant household deity, prosperous business and financial fortune have become the primary focus. Today, this practice has spread to corporate and storefront altars (even small shrines on commercial building rooftops) and roadside shrines, embedding itself deeply in Japanese society across the four tiers of shrines, temples, residences, and corporations. The annual Hatsu-uma Matsuri (Festival of the First Day of the Horse) in February marks the descent of the Inari deity and is celebrated grandly at Inari shrines nationwide.

Inugami are feared as hereditary possessing spirits tied to certain lineages, bringing wealth and prosperity yet shunned as curse gods. Rites and keeping methods vary by region, with offerings made in storerooms, under floorboards, or at water jars. Their form is not fixed: accounts describe a mottled mouse-like creature, a black-and-white weasel-like shape, a long-mouthed rat, or something bat-like. Houses said to keep inugami were believed to have as many spirits as family members, and the spirits were rumored to run to other homes to obtain desired goods. The possessed might bark, tremble in the shoulders, or gorge themselves, and even cattle, horses, and tools were said to be possessed. Exorcism was performed through prayers and esoteric rites, with shrines in Tokushima particularly noted. Origins are variously traced to sorcery, legal taboos, and rites that turn a dog’s head into a fetish, differing by locale.

The image of Inugami Gyobu should be understood through the lens of how the Matsuyama tanuki tales were reshaped by kodan storytelling. Across Shikoku, dense beliefs in tanuki and transformation legends spread, and in Matsuyama both “guardian” and “trickster” aspects were told of beings dwelling at the boundary between the castle town and the wilds. The title Gyobu signals a bond with the castle, emphasizing a guardian role, while kodan added favored conflicts—such as inviolable pacts and ambushes during internal clan strife—producing varied plotlines. In every variant, the rock shelters and caves of Mt. Kuma form the final stage, where sealing or pacification brings closure. The appearance of Ino Budayu also became standard, linking in a known monster-slaying tale from other sources and lending a higher authority of supernatural judgment to the Matsuyama tanuki narrative. His spiritual power and many retainers match regional views of a tanuki chieftain leading a band, serving as a framework to explain wonders at annual castle-town events and at passes or shrine precincts. Though today’s lore bears kodan embellishments, at its core remains the figure of a tanuki lord guarding the liminal zone between castle and mountain.

This version consolidates images of the Ipetam found across Ainu traditions. The blade rings of its own accord and shows hunger by the act described as “eating” stone or leather. Once drawn it will not rest until it sees blood, and tales say it may fly on its own to cut people. Its curse threatens households and kotan, inviting disaster beyond the owner’s will, so it is contained through rites and taboos or by sinking it in water. In Asahikawa and Kamikawa, after casting it into a bottomless bog, a rock in the shape of a sword is said to appear, tying requiem to place names and landscape origins. In Saru, a wit tale survives in which imitating the sword’s sound repels bandits, showing its fearsome name worked as a deterrent. In Kiritoi, Kushiro, an alias tale engraves taboo violation and harm into the sword’s very name, marking it as a remembered calamity object. Related types include the man-eating spear Ipe-op and the self-defense knife Sōsamusipe, suggesting a systematic view of baleful blades and weapons. This reconstruction avoids creative embellishment and adheres to regional records of the cursed sword.

A portrayal of the Ippon-datara based on records from Kii and Kumano through Nara. It is said to be one-eyed and one-legged, but firsthand sightings are rare; in many regions a single large track left after snowfall is taken as proof of its presence. Its most notable trait is appearing on December 20, the “Hate-no-Hatsuka,” a day overlapping taboos of mountain deities and roads, effectively discouraging entry into the mountains. In its link to smithing, folklore explains the one-leg one-eye form as derived from the tatara blower treading the bellows with one foot and watching the furnace with one eye. In the Obagatōge lineage it is equated with the oni-god Inosasao, once a terror of the peak but sealed by a monk and released only once a year. In Kumano and Itsukushima it is said “only footprints appear, not the body,” feared yet seldom directly harmful. While stories of one-legged snow spirits (such as Yuki-nyūdō and Yukibō) have blended with it, this entry centers on the Kumano–Nara stream, emphasizing three points: the taboo day, the single track, and the blacksmith-origin theory.

Ishikoridome, who casts the Yata no Kagami for the Heavenly Rock Cave, is the deity in that myth who makes the vessel that reflects a lost light back. When Amaterasu hides in the cave, the world goes dark. The gods gather on the riverbed of the Heavenly Yasu River and make their preparations under Omoikane's plan. The Kojiki records that after seeking out hard stone from the Heavenly Yasu River, iron from the heavenly metal mountain, and the smith Amatsumara, the gods had Ishikoridome make a mirror. This mirror later becomes the central ritual object that lures Amaterasu before the cave. In the Heavenly Rock Cave myth, making a mirror is a strikingly active deed. If the gods had only meant to wait for the light to return, they could simply have kept praying. Instead, Omoikane's plan makes, in the absence of light, a surface ready to receive it. Ishikoridome's mirror is not a trap to catch Amaterasu. It is a place for the light, showing that the world outside can still welcome the god. The mirror's surface is silent, but within that silence lives a signal: it is all right to come back. When Kokugakuin University's commentary on ritual objects reads the Heavenly Rock Cave myth as an origin story for ancient worship, the mirror stands among its key objects alongside jewels, cloth, and divination bones. A mirror has the practical use of reflecting a form, but also the power to invite a god and hold a god's presence in place. As the deity who makes this object, Ishikoridome connects the myth's beautiful surface to the heavy work of the metal shop. Fire, metal, stone, mold, and polish all converge in a single mirror set before the gods. At the Descent of the Heavenly Grandson, Ishikoridome comes down to earth as one of the Five Attendant Chiefs. The Kojiki records her as ancestor of the Kagamitsukuri no Muraji and others. This means that the craft of the mirror that guided Amaterasu at the Heavenly Rock Cave is handed on to a clan and to ritual on earth. Mirror-making is not a matter of one person's skill but a craft rooted in myth, and it becomes part of the ritual expertise that supports the Heavenly Grandson's rule. The official history of Hinokuma Jingu and Kunikakasu Jingu connects Ishikoridome, under the name Ishikoridome-no-Mikoto, to another story of mirrors. Hinokuma Jingu enshrines the great god Hinokuma with the Hikata no Kagami as its sacred body, and Kunikakasu Jingu enshrines the great god Kunikakasu with the Hiboko no Kagami. The overview relates that when Amaterasu hid in the heavenly cave, the gods followed Omoikane's counsel and, with Ishikoridome as their smith, cast sacred mirrors from the copper of Mount Kagu. Here the mirror-making deity's craft extends all the way into the worship of two great gods, Hinokuma and Kunikakasu. The Hikata and Hiboko mirrors come from a different line than the Yata no Kagami, yet they are told of as mirrors born from the same darkness of the Heavenly Rock Cave. The official overview of Hinokuma Jingu and Kunikakasu Jingu records that the two shrines, which hold these mirrors as their sacred bodies, were revered by the imperial court as treasure mirrors second only to the Three Sacred Treasures. Here Ishikoridome's divinity widens from "the deity who made a mirror" to "the deity who underpins the history of mirrors close to the imperial ancestral goddess." A mirror is a god's image, and also a vessel for welcoming the god herself. Read in modern terms, Ishikoridome is a deity of reflection and record. Mirrors, lenses, photography, film, measurement, inspection, design, metal polishing: each is a technology that renders something visible without distorting it. A myth about making a mirror in the darkness also speaks to the act of preparing tools that reflect the facts in times of confusion. Ishikoridome is not a deity who brandishes a dazzling light. She is the one who quietly makes the surface that, when the light returns, will receive it, reflect it, and give it back to the world. Her mirror is also a tool for self-recognition. When Amaterasu looks out from the cave, the mirror does not simply show the world outside; it gives the goddess her own being back. The one who hid sees her own light once more and renews her bond with the world. Ishikoridome creates the occasion for that. To make a mirror was also to prepare a surface through which a lost center could find itself again.

Iso-onna is a female sea apparition of northwestern Kyūshū. Above the waist she looks like a young woman with long black hair soaked in seawater. Below it, her outline dissolves into mist and waves without leaving footprints, or else lengthens into a serpent's body. Seen from behind, she can be mistaken for a wet rock. In Minamishimabara, Nagasaki, she stands gazing offshore; anyone who speaks to her is answered with a piercing cry, then caught in her hair and drained of blood. Her most feared habit is boarding vessels at anchor. In Amakusa, Kumamoto, Iso-onna climbs a stern mooring line after dark and covers a sleeping person's face with her hair. Boats spending the night in an unfamiliar harbor therefore lower the anchor but leave the stern untied from shore. The very line joining boat and land becomes her path aboard. Other safeguards survive around the region. On the Shimabara Peninsula, three stems pulled from a thatched covering were laid on a person's clothing before sleep so that Iso-onna's hair could not catch them. The Sōgō Nihon Minzoku Goi, edited under the supervision of Yanagita Kunio, records this coastal female apparition under names including Iso-onna and Iso-nyōbō. Iso-onna differs from Umibōzu and Funayūrei, which more often attack in open water. Her defining territory is the rocky shore or anchorage, where land and sea touch. Many communities connect her with drowned women or with a woman who died while waiting for her husband to return. In western Japan, she may also appear beside Ushi-oni, approaching first to lower a victim's guard before the other creature attacks. Hair, blood, and the shoreline boundary form the core of her image. The story of her climbing a mooring line, and the practical customs of anchoring without tying the stern or placing three reeds on one's clothing, preserve both a fishing village's fear of the night sea and its knowledge of how to live beside it.

A feared variant along Amakusa and the Shimabara Peninsula, named for slipping aboard by following the aft mooring rope. She appears as the upper body of a young woman scented with the sea, while her lower half is hazy and shifting like wave-shadows. Her long wet black hair constantly streams from her chest to the floor, branching into fine threads that cling to human skin. When a hush falls over the harbor at midnight, she stands in the lee of the shore or at a stern’s tip staring seaward, and will either echo the name of anyone who calls to her or answer with a piercing scream. At that cry she reaches a white hand to the aft rope, crosses soundlessly onto the boat, shrouds a sleeper’s face with her hair, and twists up blood strand by strand. By morning only a tide stain and a thin ring of hair remain at the pillow. Said to be the shape taken by the regrets of the drowned or a love unfulfilled by one who waited at the harbor, she is known as an isonna and also as nure-onna. The practice of avoiding the aft rope comes from this variant’s habit of treating ropes as roads. So long as she touches a line she can climb anywhere, but she does not swim about recklessly and prefers calm surfaces. On thin-moon nights some have seen her walk the water from shore, but only when the harbor tide lies asleep. She is weakened by light and prayer, so fishermen in unfamiliar ports avoid taking the aft rope, drop only the anchor, and keep the gunwale light burning. In Shimabara it is said that placing three dry thatch reeds from a roof upon one’s kimono while sleeping prevents tangling and wards her off. Those who touch her hair are seized by chill and lethargy, and the roar of the sea lingers in their ears for days. She is merciless toward mockery and rudeness, targeting first those who call her name without honorifics or taunt her with whistles. Conversely, she is said to avoid boats whose crews offer prayers for the lost at sea. Some tales claim that if you move behind her she resembles a rock shadow, and under moonlight her back becomes the outline of a wet reefs tone to let waves pass. The Isonna of the Aft-Rope Crossing is a grudge born at the liminal space of the harbor, hard to approach for those who keep the code and unforgiving toward arrogance, dropping her hair without mercy.

Edo-period strange tales and works of natural history describe Isonade as a sea monster that approaches without disturbing the surface. A crew may notice only a change in the water's color or the wind before the danger is already beside the ship. Its body resembles a shark, with coarse projections and needlelike growths extending from the back toward the tail. Isonade is most often associated with cold, cutting winds, and days of strong northerlies were treated with particular caution. Sailors avoided noisy work, put nets and ropes in order, and kept away from the rail. Such practical rules became part of the story's warning. Names and details differ from place to place, but the core remains the same: Isonade arrives invisibly, and by the time it is seen, a sweep of its barbed tail has already pulled someone overboard.

This interpretation shatters the illusion of the "innocent and brave little person" sanitized by later children's literature, restoring his true nature as the "extremely ambitious and cunning trickster" depicted in the original Muromachi *Otogizoushi*. This version of Issun-boshi carves out his destiny not through martial force, but through advanced psychological manipulation (off-board tactics) and amoral scheming. His greatest defining trait is his abnormal "upward mobility." Burdened with the supreme handicap in human society—a height of merely one sun (about 3 cm)—he never abandons his ambition to take a powerful man's daughter as his wife and achieve worldly success. His method of framing the princess using the "rice grain scheme," having her disowned by her father to socially isolate her, and creating a state of complete dependence on him, displays a cold-blooded Machiavellianism that puts modern psychopaths and con artists to shame. Even in his battle with the oni, he does not fight fair and square. He turns the desperate situation of being swallowed whole to his advantage, executing a gruesome internal destruction (assassination technique) by continuously stabbing the oni's internal organs from the safety of its body (stomach and eyeballs) with his needle-sword. Finally, he robs the oni of its treasure, the "Miracle Mallet," using it to rapidly grow his body and ultimately obtain the ultimate social status of a "perfect human man." He represents the darkest and most realistic rags-to-riches hero in Japanese literary history, overturning his inherent, irrational handicaps entirely through intellect, lies, and the plunder of otherworldly power (the oni's treasure).

Drawing on the Konjaku Monogatari-shū, later scholarship calls it “Ita-oni” (Board Ogre). The entity is either a board itself or a phenomenon dwelling in a board, taking a plank-like form that juts from roof beams or lattices. Its motive and will are unstated, but its core act is crushing sleepers to death. In Heian court and aristocratic residences, night watch and gate duty were crucial, and tales of the uncanny often served to reinforce discipline. Here too, it bypasses two armed men and strikes a defenseless sleeping place, embodying the ethic that negligence invites death. While it aligns with the idea of spirits inhabiting objects, it lacks tales of aging into autonomy or growth, and is told as a transient manifestation of a specific board appearing to suit the scene. There are no records of pursuit or capture, and it appears and vanishes swiftly without leaving traces.

A monstrous bird that appeared night after night above the Shishinden in the plague-stricken capital in the autumn of 1334, crying "itsumade, itsumade." In Taiheiki it is shot down by Oki no Jirōzaemon Hiroari; in the Edo period Toriyama Sekien named it Itsumade after its cry. Shōwa-era yokai books describe it as a bird that cries beside the unburied dead.

Ittan-Momen is a cloth-like being recorded as fluttering through the night in the Ōsumi Takayama region and attacking people. A 1942 dialect collection describes “Ittan-Monmen” as something like a length of cotton cloth about one tan long. Later local accounts tell of it winding around heads and necks, while Shigeru Mizuki’s design gave it a form known across Japan.

Based on Edo-period records and regional folktales. An aged char trout appears in the guise of a Buddhist monk and speaks to anglers. It often urges moderation, citing the temple’s domain or the pool’s lord, and departs quietly if given alms. Later it may be caught as a great char, where rice or rice cakes given as alms are found in its belly, revealing its identity. The motif reflects reverence for river and pool guardians and ideas akin to eel and other water deities. Depending on region, it appears as a harmless, didactic type, a warning type bearing deadly poison, or a salvific type that sacrifices itself to stop a levee breach, yet all embody folk norms that safeguard the boundary between waters and livelihoods.