Taking the form of a giant shark (eight-fathom wani) in the *Kojiki* and a dragon in the *Nihon Shoki*, she is the grandmother of the first emperor and the maternal origin of the seafaring Azumi clan. A sacred deep-sea shrine maiden symbolizing pearls, whose legends live on in Udo Jingu's Breast Rock and Watadzumi Shrine.

"Kappa" is not, in truth, the name of any single creature. It is a collective term—the word by which the whole of Japan, each region in its own dialect, has called the water spirits that dwell in rivers and ponds. In southern Kyushu it is the Garappa; in Tōhoku, the Medochi; in Shikoku, the Enko; in Chūbu, the Kawaranbe; in Kinki, the Gataro; in Kyushu again, the Hyosube. From place to place the name and the form shift a little, and the total is said to exceed eighty. Some are close to monkeys, some shaggy with fur, some moving in troops. Yet all share a common core: they live by the water, hold water in the dish on their heads, and drag away people and horses. The kappa, in other words, is the shared name of a vast clan into which all the water spirits of the land have gathered. It is the reading of folklore studies that binds these many variants into one. Yanagita Kunio and Orikuchi Shinobu held that the kappa was originally a god who governed water—a water deity—who declined into a yokai as belief in it faded. The fact that in the komahiki legends the kappa always tries to pull a horse or ox into the water may itself be a memory of festivals in which horses and oxen were offered to a water deity in prayer for a good harvest. In Kappa Komahiki Kō (1948), Ishida Eiichirō compared this bond between horse and water deity with myths from across Eurasia. Precisely because it is a god of water, the kappa draws water to the fields, grants fish, and even hands down bone-setting remedies—while also drowning people and pulling out their shirikodama. Its twin aspects, blessing and curse, are the two sides of a fallen water deity. Traces of the water deity show even in the turning of the seasons. Across western Japan it is widely told that at the autumn equinox the kappa goes up into the mountains to become a yamawaro, and at the spring equinox comes down again to the river to return to being a kappa. The field god who descends from the mountains to the villages in spring, the mountain god who returns to the peaks in autumn—that idea of coming and going maps exactly onto the exchange between kappa and yamawaro. In this way the clan’s variants, too, are bound to one another as a single continuous terrain. The clan even has its legend of a chieftain. On the Kuma River in Kyushu the tale survives of Kusenbō, a kappa general who crossed over from the continent at the head of nine thousand kindred. Having drawn the wrath of Katō Kiyomasa, he was driven from the region, moved to the Chikugo River, and became one of the retainers of the Suitengū shrine in Kurume. That a kappa was imagined not as a lone monster but as a clan linked from river to river is plainly expressed in this tale of a boss. Places tied to the kappa are found all over the country. At Tōno in Iwate there is a "Kappa Pool" (Kappa-buchi) where kappa are said to appear, and at Jōken-ji temple, in honor of a kappa that put out a fire with the water from its head-dish, stand "kappa guardian lions" whose heads are shaped like a dish. At Lake Ushiku in Ibaraki the painter Ogawa Usen, who depicted kappa all his life, was called "Usen of the Kappa," and Tanushimaru in Fukuoka styles itself "the birthplace of the kappa clan." In the Kappabashi district of Tokyo a legend tells of Sumida River kappa who came each night to help a merchant pressing ahead with flood-control works. To this day kappa festivals are held in many places, and the kappa lends its name to sake brands and town mascots alike—remaining the most beloved of all Japan’s water yokai.

Umibōzu is often understood as a yokai born from the fear and unease of people at sea. It has no single fixed form: sometimes it is no more than a black shadow, while in other stories it rises from the water as a colossal monk. One well-known variant has it draw close to a boat and whisper, “Lend me oil.” If the crew complies, it is said to kindle a fire and sink the vessel. Later variants add different details. Some say it has a collector's habit, gathering wrecked boats and fishing nets and piling them on the seabed; others describe it appearing with a glowing bottle or lantern in hand. It frightens those who meet it, yet it also stands for the unfathomable mystery of the sea and is regarded with awe as well as fear.

Tsukuyomi's Position Among the Three Precious Children. While the basic description touches upon Tsukuyomi's primary myth, this detailed explanation delves into the deity's unique structural position within the "Three Precious Children" (Mihashira-no-uzu-no-miko). The tripartite rule by Amaterasu Omikami (Takamagahara, day, light), Tsukuyomi (Yoru-no-Oskuni, night, moon), and Susanoo-no-Mikoto (the sea, untamed force) established the three domains of day, night, and wild power in ancient Japanese cosmology. However, Tsukuyomi alone has almost no detailed mythological narratives throughout the *Kojiki* and *Nihon Shoki*, disappearing from the center of the story immediately after being entrusted with the "Yoru-no-Oskuni." The discrepancy between the high structural position as the middle child and the sparsity of mythological activity is a major point of discussion in the study of ancient Japanese mythology. The Slaying of Ukemochi — A Contrast with the Kojiki. Tsukuyomi's primary mythological tale, the slaying of the food deity Ukemochi, is recorded only in the *Nihon Shoki* and does not appear in the *Kojiki*. In the *Kojiki*, this identical narrative motif is performed by Susanoo-no-Mikoto against Ogetsuhime. This indicates that ancient Japanese mythology possessed a single narrative template for the "origin of grain = five cereals sprouting from a deity's corpse," which was assigned to different deities (Susanoo vs. Tsukuyomi) in the two texts. The difference in this allocation is a vital piece of evidence for examining the compilation process, variant transmissions, and cosmological consistency of ancient Japanese myths. The editorial intent of the *Nihon Shoki* in assigning the Ukemochi murder to Tsukuyomi is interpreted as an effort to emphasize the connection between the moon and the agricultural calendar. Comparative Religion of a "Quiet Deity". Tsukuyomi's "quiet, reclusive" personality is unique even when compared to lunar deities worldwide. From Selene and Artemis in Greece, to Luna in Rome, the Persian moon god Māh, the Chinese lunisolar calendar, and Korean lunar spirits, moon deities across the ancient world are often depicted as highly active and central figures. In contrast, Japan's Tsukuyomi is rare for having few myths and an emphasized serene, introverted, and mediatory nature. Scholars such as Shinobu Orikuchi and Eiichiro Ishida deciphered this characteristic, concluding that "the Japanese moon deity has a 'watchful' nature," and organized the ancient Japanese relationship with the moon not as one of "direct worship" but as a connection of "quiet watchfulness." Moon and Immortality Beliefs — Okinawa and East Asian Comparisons. Nikolai Nevsky, Shinobu Orikuchi, and Eiichiro Ishida positioned Tsukuyomi's primitive attributes within the broader East Asian beliefs linking the "moon and immortality". In Okinawa and the Ryukyu Islands, there is a tradition of "Sudemizu" (water of molting or rejuvenation), a water of immortality bestowed upon humanity from the moon, indicating a symbolic link between the moon's "molting" (the cycle from full moon to new moon) and immortality/rebirth. Similar "moon and immortality" beliefs are distributed across China, Korea, Mongolia, and Southeast Asia, framing the prototype of Tsukuyomi as a Japanese variation of this widespread belief system. The moon's periodicity, its association with feminine tides, the agricultural calendar, and the mystery of its waxing and waning all multi-layered the ancient faith. Gassan Shrine and Shugendo. Gassan Shrine in Yamagata Prefecture, a former Kanpei-taisha (Imperial shrine, 1st rank), served as the core of the Three Mountains of Dewa (Mt. Haguro, Mt. Gassan, Mt. Yudono) and became a center for mountain worship and Shugendo from the Heian period onward. Mt. Gassan is an extinct volcano standing 1,984 meters tall, where Shugendo practitioners envisioned a "Pure Land where Tsukuyomi resides" at the summit, aiming for the rebirth of the soul through rigorous mountain asceticism. Within Shugendo, Tsukuyomi developed uniquely as a deity symbolizing the "moon of death and rebirth," occupying a significant position within the complex evolution of mountain worship, Shugendo, and Pure Land Buddhism during the Heian, medieval, and early modern periods. Even today, the "Gassan-mode" (pilgrimage to Mt. Gassan) is carried on as a symbolic custom of Tohoku folklore and Shugendo. The Geography of Tsukuyomi Shrines. The enshrinement sites of Tsukuyomi are distributed across four main lineages: (1) Gassan Shrine in Yamagata Prefecture (Tohoku mountain worship); (2) Tsukiyomi Shrine in Kyoto (central Shinto under the ancient Ritsuryo system); (3) Tsukiyomi-no-miya and Tsukiyomi-no-miya as auxiliary shrines of the Inner and Outer Shrines at Ise Jingu in Mie Prefecture (State Shinto and the Ise Jingu system); and (4) Tsukiyomi Shrine in Iki City, Nagasaki Prefecture (the oldest Tsukuyomi shrine in Japan, tracing the Korean Peninsula route). The Kyoto shrine is considered to have derived its spirit from the Iki shrine, serving as valuable folkloric-geographical evidence showing the route through which lunar worship originating from the continent and the Korean Peninsula was transmitted to ancient Japan. This demonstrates that Tsukuyomi worship is not an isolated phenomenon unique to Japan but the result of formation within a broad East Asian network of lunar beliefs. Tsukuyomi in the 21st Century. In postwar Japanese subculture works—such as the *Megami Tensei* game series, *Okami*, and the "Moon Breathing" in the manga *Demon Slayer*—Tsukuyomi's attributes of tranquility, mystery, isolation, and dark-night moonlight have a high affinity with modern character design. The symbolic deity of "night, moon, tides, calendar, and immortality" in ancient Japanese cosmology continues to acquire new meanings in the 21st-century era of globalization, space exploration, and social media. Pilgrimages to Mt. Gassan, Ise, and various Tsukiyomi shrines are inherited today, and the serene, mysterious lunar faith has been deeply rooted in the spiritual culture of the Japanese from ancient times to the present. The fact that the deity with the least mythological activity continues to live on in the most serene form within modern Japanese spiritual culture symbolizes the profound wonder of how mythological culture is passed down.

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.

The Funayūrei of Dan-no-ura are said to be the shades of the Taira who sank in the Battle of Dan-no-ura. On misty nights where currents meet in the western sea, they draw alongside a boat with water streaming from their armor and quietly ask for a teigo—a hisage, or handled pouring vessel. Their faces are white, their eyes reddened by salt, and their voices hoarse, yet their words still preserve the etiquette of the warrior class. They keep the order of their former battle lines even at sea: one spirit calls out first, then countless hands seize the planks together. If the bowl or ladle they receive has an intact bottom, they use it to pour seawater into the boat until it sinks without a sound. People who crossed these waters therefore pierced the bottoms of such vessels in advance and kept them tied beside the rail. When the ghosts accept one, the water runs straight through, and their rancor disperses with the tide. If a monk holds a memorial service and chants sutras, the silhouettes of their jingasa dissolve into the sea mist and the clink of armor chains returns to the sound of the waves. They do not attack everyone without cause. The stories bring them closest to people who ignore maritime custom or arrogantly treat the sea with contempt, as if the dead meant to impress the memory of the Taira defeat upon the living. On the sixteenth day of Bon, during the equinoctial weeks, or on an anniversary of the battle, the quieter the sea becomes, the nearer the tread of armor seems. Ghost lights line the water like watchfires, reproducing the fleet of long ago. Ash, rice cakes, fragrant flowers, and dumplings can soften their fixation. Cast from the bow, an offering may bring back a single wave like the sleeve of a shirabyōshi dancer and push the vessel onward. Some accounts say an unflinching stare can also make them withdraw. Elders explain that this is not a contest of will: when the living truly face the dead, the stagnant resentment begins to loosen. Yamaoka Genrin described apparitions as a congealing of ki; here, soot-dark grievance takes shape upon the current. When the wind changes, sutras sound, and offerings sink, that loosened force scatters back into the sea. These Funayūrei are therefore not creatures of terror alone. Remembrance can bring them rest. A child's outline sometimes appears among their ranks. Its voice is finer still, and it asks for no water; it only hooks small fingers over the rail. If the faint bells of armor can be heard, the crew should steady the helm, take the Hayatomo current at an angle, and send a murmured nembutsu into the wind. The battle-dead adrift in the western darkness yield only to proper rites and compassion.

While the *Yamawaro* is a mountain monster unique to the mountainous regions of Kyushu, its greatest originality lies in the fact that it forms two aspects of a single body with the *kappa*. The fact that Terajima Ryoan noted the habitation of *Yamawaro* in Chikuzen and Goto in *Wakan Sansai Zue* is evidence that early modern intellectuals incorporated the folklore of grotesque beings from the western mountains into the framework of natural history, showing that the Goto Islands were designated early on as a land of *Yamawaro* traditions. In the migration belief, it is said that the *kappa* of the river and the *Yamawaro* of the mountain switch places at the boundary of the spring and autumn equinoxes, which is thought to be a crystallization of the agricultural calendar, water god worship, and mountain god worship into a single existential image. Its assistance to woodcutters and the reward of rice balls, its love of sumo, its dietary preference for salt and crabs, and its grotesque form with dog ears, red hair, and a single eye are all supported by the *Wakan Sansai Zue* and the oral traditions of various parts of Kyushu. Amidst life in the Goto Islands, surrounded by sea and mountains, the *Yamawaro* has become inextricably linked to the *kappa* (*gataro*), becoming an entity that embodies the local spirituality penetrating both the waterside and the mountains.

Misogoro boasts a body so massive that he can sit on Mount Unzen and wash his face in the Ariake Sea, and his every movement is said to have carved the geography of the Shimabara Peninsula. His braced footprint on Mount Takaiwa became Suwa Pond, and the dirt he tossed aside while farming became Yushima (Dangoshima) Island. This chain of origin tales elevates him from a mere apparition to a creator-giant who birthed the peninsula's landscape. The extraordinary diet of licking four *to* of miso a day is a rustic narrative device measuring the giant's body against local staple goods, inseparably linked to the miso-brewing lifestyle of the peninsula. While belonging to the *Daidarabotchi* giant lineage, the unique aspect of the Shimabara version is that he is described with a mildness that helps people without malice. Today, he lives on as a symbol of local heritage in Minamishimabara City through statues and festivals.

While the *Gataro* is a lineage of the Kyushu *kappa*, its image unique to Goto lies in the fact that it formed an independent belief as a guardian deity of fire prevention. The legend that the general of the *kappa* of Goto dwells in the Mizu-jinja on the Daienji River in Fukue Island, and that *kappa* firefighters protected the Goto domain's mansion in Edo during a fire in Kyoho 8 (1723), connected with the nationwide Suitengu belief of 'water god = fire prevention,' and became known even in Edo via the Goto domain's mansion. Its form possesses the typical features of Kyushu *kappa*, such as the dish on the head, detachable arms, love of sumo, and human possession. However, it has thick traditions linked to local place names, such as the differences in island names like Gaataro, Kyataro, and Gappadon, and the kappa footprints remaining on Bentenjima in Shiraragahama, Miiraku. Sometimes spoken of as the alter ego of the *Yamawaro* that switches places seasonally, the *Gataro*, in Goto—surrounded by the sea and with limited clear streams—is a *kappa* rooted in island life, harboring the contrasts of water and fire, mischief and protection within a single body.

Early modern Japanese accounts of Kaijin drew on two streams of information: reports imported from overseas and descriptions in domestic natural histories. The traditions eventually overlapped. Kaijin is broadly human in shape, but webbing between the digits and loose skin over the entire body set it apart. The skin gathers in folds at the waist and looks almost like a wide pair of hakama. Whether it understands language is uncertain. Most sources say it neither comprehends human speech nor answers, although a variant claims that one survived on land for an extended period. Its diet is equally unclear because many accounts emphasize its refusal of food offered by people. When a captured Kaijin is kept away from the water, it weakens quickly and may die within days. Some have suggested that observers mistook a sea lion or seal for a human figure. Another explanation treats the apparent clothing or folds as seaweed clinging to the body. Neither has been proven. Part of the tradition came through Nagasaki in reports carried by ship, and part came from sightings along the Japanese coast; names and dates differ from source to source, so the material cannot be reduced to one clearly defined animal. Kaijin is best understood as a representative early modern account of an uncanny creature captured at the edge of the sea.

This form of Shiranui appears in ordered ranks before dawn on the first day of the eighth lunar month. Several kilometers offshore, one or two reddish lights first emerge. Coastal people call them oyabi, the 'parent fires.' They split to either side, producing more and more 'child fires' until hundreds or thousands form a single band across the sea. Tradition lets the line extend four to eight ri, roughly sixteen to thirty-two kilometers. It is almost invisible from a beach close to the water but clear from a headland or rise about ten ken above it. Around the deepest ebb of the tide, the lights settle into their most regular pattern, flickering behind the waves like the scales of a submerged dragon. The fires retreat when chased and draw away when a boat comes near. Anyone who tries to capture them sees both light and reflection slip aside, leaving only a direction back toward shore. An old account says that such a parent fire appeared when Emperor Keikō's vessel was surrounded by darkness and turned its prow safely landward. Coastal communities therefore treated the flame whose maker no one knew with reverence. On the night of Hassaku they stopped their nets, rested their oars, and waited for the line to come apart. Although the parent fires are sometimes linked with the presence of a violent dragon deity, they are not said to delight in harming people. Their lesson is against arrogance and haste. A boat intent on quick profit may wander among the lights and finally be forced to furl its sails. Someone who listens to the tide instead climbs a shore pine, studies the rhythm of the flames, and leaves quietly through a break in the line. The shoals then prove unexpectedly calm, and on the return journey a last light may sway against the shore as though welcoming the boat. Villagers call the display Thousand Lanterns or Dragon Lanterns and press their hands together. If people shout its name crudely or mock it, the ordered lights scatter at once into sea fog. Wind does not feed Shiranui as it would an ordinary flame; the lights grow and diminish only with the pulse of the tide. That is why they form a clean band from a cape or mound while vanishing at the water's edge. A seaside shrine rope bending slightly toward the water, or a change in the color of a lighthouse flame, is also said to warn that the offshore lights are beginning. Elders who know the signs tell young crews that the tide is falling and the fire will rise, and advise them not to sail. No ash or smoke remains. For a brief hour after dawn, shells on the tidal flat are said to glow pale rose and dew on the reeds to keep the fire's last color. On such mornings, villagers scatter salt on the beach and give thanks for the lives guided home. The parent fires open a way for those who understand awe and courtesy, retreat from the overconfident, and quietly draw the boundary between human beings and the sea anew.