Blue is the wrong color for fire. That single wrongness — flames where nothing burns, in rain, over water — generated the largest family in the whole night parade, and Japan's genius was to give each light a name and a life story.
The class: onibi — demon-fire generally: blue, rain-loving, graveyard-adjacent, swarming "20 or 30 at once." Within it, the taxonomy:
The human soul in transit — hitodama: the tailed flame leaving a deathbed for the temple; attested since the Man'yōshū; joined by the deathbed-farewell tradition of the ikiryō.
The punished, by name. Four lights are convicted oil-thieves — lamplight was wealth, and stealing it made ghosts: the shrine-oil crone ubagabi (Osaka; say "oil-pourer" and she vanishes), the temple-oil monk sōgenbi (Kyoto, his agonized face in the flame), the pressed-oil exile abura-sumashi (Kumamoto — "I still appear!"), and the Jizō-oil merchant reborn as the lamp-licking abura-akago (Ōtsu). A fifth burns for something worse than theft: the kazenbō of Toribeyama, the self-immolated priest whose letting-go was incomplete.
And the sentence fits the crime exactly. A temple lamp was community light — a visible, recurring donation, paid for by people who could not easily spare it, burning on trust in a place nobody was watching. So: you stole light, and now you are light — burning in public, face showing, indefinitely. Not an execution but a sentence to visibility, precisely inverting a crime committed in the dark. That two different prefectures — a crone in Osaka, a monk in Kyoto — independently reached the same verdict is the folk economics of lamp-oil, preserved.
The contact fire. One light in this family doesn't keep its distance: the minobi of Lake Biwa blooms on your straw raincoat on rainy nights, cold as firefly-light — and multiplies every time you brush at it. The only cure is to strip the coat off and walk home wet. The yokai takes the raincoat; you keep the night. Composure again, in flame. And the rōjinbi of the Shinano border is the family's loneliest: a flame and an old walker, together, on the worst nights, which water cannot extinguish — beaten only with animal hides, or rerouted by holding your footwear over your head.
The animals. Fox-fire — kitsunebi (kitsune) — lights the fox's wedding processions; the aosaginohi is the family's control specimen: the glowing night heron that Edo observers identified, sword-tested, and kept as a yokai anyway. The basan breathes fire that doesn't burn; the tsurube-otoshi's bucket-fire drops from trees.
The lights that made history. The shiranui of the Yatsushiro sea — one flame splitting into thousands across eight kilometers — named a province (Hi, "Fire," today's Kumamoto).
And its folk record is very nearly a scientific paper. The tradition specifies reproducible observing conditions: the dark of the seventh lunar month, weak wind, and specific viewing heights — invisible from a boat, visible from ten metres up. Yamashita's optics later explained it as a refraction mirage of house lights and fish-luring fires through thermally layered air over the tidal flats — and every folk condition turns out to be exactly what that requires: the season (cold air over warm tidal water), the calm (layers don't survive wind), and the height (you must look along the refracting layer, which is why boats see nothing). Centuries of attention produced a correct observing protocol, filed under "fire nobody knows."
It is also going out. Land reclamation around the Ariake flats has altered the geography that produced it. A phenomenon that named a province, and that people knew exactly how to go and watch, is being switched off by drainage.
And the aoandon waits at the end of the hundredth tale — the lamp the stories themselves put out.
The science sidebar, once for all: phosphine, marsh gas, bioluminescence, refraction, ball lightning, afterimage — the period's own skeptics proposed most of these, and the lights kept their names. The experience was always real; the biography was the point.