The yokai have no unbroken oral lifeline to antiquity. What they have is better documented: a relay of writers, one per era, each of whom saved the tradition and changed it. Every provenance note in this bestiary traces back to these nine desks.
Abe no Seimei (921–1005) — the practitioner. Court diviner of the Onmyōryō, historically real, legendarily fox-born (Kuzunoha's son). In him the state managed the invisible as a government function — the yokai's first professional counterpart.
Toriyama Sekien (1712–1788) — the cataloguer. Four illustrated volumes, 1776–84: part folklore, part literary allusion (his borrowings from the Tsurezuregusa alone fill seven entries here), part outright invention signed with puns. This bestiary's load-bearing rule is his legacy: "appears in Sekien" attests the image, never the belief. The first man to discover that a well-made catalog generates folklore.
Lafcadio Hearn & Koizumi Setsu (1890s–1904) — the transmitters. Setsu retold; Hearn wrote; the world received (yuki-onna, Hōichi, Mujina) — and Japan received it back, translated. Seven of the primary texts archived for this bestiary are theirs.
Inoue Enryō (1858–1919) — the debunker. Founded yōkai studies to kill its subject — and his demolition survey became the tradition's most complete Meiji archive. The essential negative: even the eraser wrote it all down.
Ueda Akinari (1734–1809) — the novelist. In 1776 — the same year Sekien published his first catalog — Akinari gave the kaidan its literary summit with Ugetsu Monogatari. Where folk tales record what happened, Akinari wrote from inside: his jealous wife reasons, his flesh-eating monk falls step by step, his vengeful emperor argues like a man who has had six centuries to prepare. Smallpox deformed his hands in childhood — "an experience that shaped his lifelong belief in the supernatural." One year, two Osaka men, and the tradition acquired both its look and its interior.
San'yūtei Enchō (1839–1900) — the performer. The rakugo master who made the ghost story a solo art, and who introduced background instrumentation and altered stage lighting for his kaidan — "a trend which would become standard today." Mood lighting was invented for yokai. His Botan Dōrō and Kasane-ga-fuchi set the modern shape of both; J-horror's slow withheld pacing is arguably his stage timing, filmed.
Yanagita Kunio & Sasaki Kizen (1910–) — the founders. Tōno Monogatari made the scraps into a science; his theories (fallen gods, one-eyed servants, demoted giants) are the scholarly stratum flagged in a dozen entries here.
Orikuchi Shinobu (1887–1953) — the other founder, working the opposite direction. Where Yanagita went out and asked people, Orikuchi reasoned from concepts outward; the Japanese name for his output is simply Orikuchi-gaku. He supplied two of this bestiary's load-bearing words: marebito, the visiting deity who arrives from Tokoyo to be hosted and sent back — the scholarly root of every masked-visitor practice here — and yorishiro, the vessel a god descends into, which he coined in 1915. Read together the two founders cover both axes: Yanagita explains what a spirit becomes when nobody feeds it; Orikuchi explains what happens when somebody does, annually, on the correct date.
Mizuki Shigeru (1922–2015) — the reviver. Kitarō decided which yokai are famous; his encyclopedias mixed rescue with ~30 unlabeled inventions; his pen rewrote witnesses' memories. Sekien's true heir, in both senses.
The relay's one-line summary (from the Mizuki dossier, where it belongs): the yokai survive because, in every century, somebody wrote them down — and every writer added some of their own. This site is the relay's next runner, and it differs in exactly one ambition: to be the first that labels its additions.