Aosaginohi, orAosagibi (青鷺火, "blue heron fire") is awill-o'-the-wisp type phenomenon in the night, a ball of flame or strange glowing light (hikarimono), explained as people mistaking theheron's glittering wings and glowing eyes.[1] Theao sagi (青鷺;lit. "blue heron") in moderntaxonomy refers to the Eurasiangrey heron.
The strange light phenomenon is also calledgoi no hi (五位の火; "fifth rank fire") orgoi no hikari (五位の光; "fifth rank light") wheregoi sagi (五位鷺;lit. "fifth rank heron") refers to aspecies of night heron.
Theaosagi-no-hi appears in the illustratedyōkai compendium,Toriyama Sekien'sKonjaku Gazu Zoku Hyakki (pub.1779), whereasgoi no hikari appears in Tōsanjin'sEhon hyaku monogatari (1841) illustrated byTakehara Shunsen [ja]].
Since the Edo Period, these mystery lights have been explained away as herons whose wings and eyes glowed in the dark as they flew.[2] Tōsanjin and other writers have added this was merely an example of naturally occurringbioluminescence.
Rumor about a glowing heron being killed and eaten by a samurai occurs inMimibukuro [ja] (1805), and other works into the modern period record instances where people claimed to have seen unusual glowing lights connected to herons, ducks, etc.
There is a mix ofao sagi fires andgoi sagi lights attested in past literature and folkloric records, considered cognate phenomena.
In the physician Nakayama Sanryū (中山三柳)'sDaigo zuhitsu (醍醐随筆; "Cream-of-the-crop essays",Kanbun 10/1670), a certain person thought he shot ahikarimono (光り物; "glowing object"), but it turned out to be anaosagi (鵊鶄, lit "blue heron"), i.e., a glowing bird. Theleishu type Japanese encyclopediaKōbunko [ja] which quotes this passage from this work files it under thegoisagi subsection and not theaosagi subsection,[4][5] and these same characters (鵊鶄) is typically readgoisagi in other quotes from works, below.
Yamaoka Genrin [ja]'sKokon hyaku monogatari hyōban [ja] (pub.Jōkyō 3/1686]) describes a strange recurrent fire or light phenomenon (cf.aburabō [ja]), with the attached story as follows: an easternŌmi Province oil merchant who had supplied oil to the Main Hall (chūdō) ofEnryaku-ji had been revoked its 10,000koku (annual rice harvest volume) of land privilege (chigyō [ja]), and with the business floundering, died in misery. Afterwards, strange glowing objects were seen near the site of that oil merchant's business, and seemed to be drawn to oil-lit light, so the phantasm was dubbed "oil thief" (though it did not actually steal). Someone even claimed to have seen a shaven flying head blowing fire. The author Genrin weighs in on the events and concluded these were "blue heron" sightings. A heron of advanced aged, he writes, always gleams when flying by night, glowing its eyes in sync, with thebeak is pointed ferociously.[a] This is naturally often mistaken for ahikarimono (phantom light).[7][8][9]
A comparative cognate example[8][10] is the story inKikuoka Senryō [ja]'sShokoku rijindan [ja] (pub.Kyōhyō era/1741–1744) concerning the eerie "hag fire" story (cf.uba-ga-bi).[3] The tale is set in Hiraoka,Kawachi Province (laterHiraoka [ja],Osaka). An old woman who was stealing lamp oil was rumored to have turned into auba-ga-bi (姥ヶ火;lit. "hag fire"). But there was a witness who saw it land nearby, and he lay flat to observe furtively, and discovered it to be a chicken-like bird, and heard beak-tapping sounds. It flew away after a short pause, but the man saw that in flight it looked like a round-shaped fire from a distance. The author concludes it must have been a night heron (goisagi).[11][8][12]
The encyclopediaWakan sansai zue (pub.1712 has an entry forgoisagi (鵊鶄; "night heron"), which in its flight seemed like fire, looked especially bright on a moonlit-night, so that people were wont to mistaken it for ayōkai.[13][14][15]
According to Noda Shigegata (野田成方)'sUrami kanwa (裏見寒話; "Reversal view cold tales") (preface datedHōreki 2/1752), which was aKai Province geographical treatise, there was a grass plain called Mikazuki-hara in Senzuka (now part ofKofu, Yamanashi) where fire appeared at night and looked like lanterns from afar. The geographer adds that whenever a fire about the size of akemari (Japanese soccer) ball appeared in thepine andsugi forests, bobbing up and down, coastal folk called it "sagi-bi" or "heron light". It was explained by someone that when the "blue herons" perch on trees and get shaken in the wind, their wings will shimmer.[16][14][b]
The bird-glow is also featured in the well-known illustrated compendia ofyōkai from the period, namelyToriyama Sekien'sKonjaku gazu zoku hyakki (pub.1779)）and writer Tōsanjin and illustratorTakehara Shunsen [ja]'sEhon hyaku monogatari (1841).
Sekien's "Aosagi-no-hi" page (cf. fig, right) bears a caption which reads that an aged "blue heron" (translated asgrey heron) has gleaming wings in night flight, with eyes aglow, and "their beaks are fiercely sharp", etc. (nearly the same description as given by Genrin discussed above).[c][17][18]
In theEhon hyaku monogatari, Shunsen's illustration (cf. fig, above right) of the "Goi-no-hikari" (lit. "fifth rank glow", i.e. "night heron's glow") explains in caption that the bird was bestowed the courtly fifth rank, and began to lighten up its surroundings with its luster.[19] The book also contains prose text penned by Tōsanjin, which delves into theying-yang theoretical consideration on flames, and states "when on sees the fifth-rank heron (night heron) resting in the pitch-dark night, it appears like fire glowing blue", adding that the phenomena of glow-in-the-dark abound in the natural world, etc.[20][14]
Thekibyoshi genre writerKoikawa Harumachi [ja]'sBakemono shiuchi hyōbanki (妖怪仕内評判記; "Compilation of Monster Critiques", pub.An'ei 8/1779) (cf. fig. right) is a book about the bossyōkaiōnyudō holding a contest ofshiuchi or tricks to be played on humans, in order to rank them. Theaosagi blue heron ranks second, for it turns into an eeriehikarimono glowing objects by night to frighten people, and according to Harumachi, transforms into a burning pillar about 5 feet (shaku) tall. The bird shrinks its neck thus mimicking the shape of a square pillar, and flaps its wings crossed over to simulate flickering flames, according to this writer.[21][22]
Some years later, anothergesaku (burlesque) writerSakuragawa Jihinari [ja]'sBakemono haruasobi (変化物春遊; "monsters' spring trips/jests", pub.Kansei 5/1793) claims that inYamato Province there stood a largewillow tree from which blue flames could be seen on a nightly basis, and hence calledbake yanagi ("freak willow"), and people avoided it. One rainy night, a man thought he was confident no fire will burn during a downpour, and approached, whereupon the willow grew bluer than ever and the man collapsed. The phantom light was caused by the "blue heron" according to the storyteller.[23][24][14]
The miscellanyMimibukuro [ja] records an event around the autumn of (Bunka 2/1805), where a man fromYotsuya, met a person clad in white without a lower body in the streets during the night, and suspecting it to be a ghost, turned around to see a glowing single eye, so he abruptly slashed it with a sword. When the man stabbed the fallen creature for the final blow, it turned out to be a heron. He kept the heron and ate it, so the rumor spread that he ate ghost stew.[25][14][10]
Katō Jun'an'sSaezuri gusa [ja] (written duringTenpō era toBunkyū 3,c. 1833–1863; published 1910) explains that aying fire is blue light without a flame, and emitted by such animals asfoxes,weasels, night herons,jellyfish,octopi, andfireflies.[26]
Witness reports are plentiful that grey herons and night herons glow blue-white, just like the fabledaosagi-no-hi.[2]
there are also legends that the heron flies while carrying a burning piece of branch in its mouth, or that it spits fire. In theMetropolitan Tokyo area, there has been a reported sighting of the night heron spewing fire at the surface of theTama River.[27]
OnSado Island,Niigata Prefecture in what used to beNiibo [ja] village (now part ofSado city), legend has it that strange fire phenomena called "dragon lantern" (ryūtō [ja]) were seen flying almost nightly by the localume tree atKonpon-ji [ja] temple. When someone shot it with an arrow, it turned out to be a heron.[28]
Ibaraki Prefecture's local historian Kimimori Sarashina (更科公護) published an instance of him witnessing fuzzy blue-white light flying around May or June c. 1928, in the city ofChikusei, and remarks that night herons are often said to glow.[29] InIbaraki township, he saw ayoshigamo (falcated duck) and akarugamo (Eastern spot-billed duck) glowing.[30] Another local historianMitsuji Zama [ja][d] reported the folklore aroundKasumigaura, Ibaraki that a heron supposedly turns into a fireball.[31]
In the aforementioned 1712 encyclopediaWakan sansai zue there is already the observation that the luminescence of a night heron flying at night has been taken to be ayōkai phenomenon by people at large.[13][14] AndUrami kanwa (1754) compares the "heron fire" phenomenon to seeing spark-lights from a cat stroked against the grain in the dark, and conjectures something similar can happen with birds' wings.[16]
There are legends that night herons which attain a certain old age become enchanted like thekitsune fox ortanuki raccoon dog. Such legends may have emerged from the sheer creepiness of the nocturnal night heron crying loudly and flying in the night sky. There are fanciful tales of night heroes developing pectoral scales, scattering yellowish powders, thus emitting blue-white light while flying in the clouded sky around autumn time.[34]
One plausible scientific explanation is that certainbacteria may attach themselves to a waterfowl's body, and glow under moonlight. Or white tufts of feather on the night heron's breast may appear to glow when seen in the dark.[34]
As for species identification, even if the story of theuba-ga-bi inShokoku rijindan[3] or theMimibukuro rumor uses the bird namegoisagi, this does not necessarily mean precisely that species (according to moderncommon name conventions) had been meant, observesTeiri Nakamura [ja].[10] And while the saiduba-ga-bi was stated as being a chicken-like fowl, the beak-battering behavior suggests not night heron but acrane, inMinakata Kumagusu's opinion expressed in a letter.[35]
Azuma kagami's entry for 14th day of 6th month ofKenchō 8 (7 July1256 in theJulian calendar）reports ahikarimono seen, more than 5shaku (feet) in size that first look like a "white heron" (egret) then was like red fire, leaving a trail like white cloth being pulled. It was seen not only inKamakura but from neighboring provinces as well. It states this was a type never seen in Japan.[36][37] TheKoji ruien classifies this as a celestial (astral) event, alongside the giant 44shaku (feet) meteor ofShōka 2/1258.[38][e]
Thekaidan novelistKyōka Izumi wrote two related short stories under the titles "Sagi no tomoshibi (鷺の灯)" and "Aosagi", collected inKōya hijiri [ja].[19]Natsuhiko Kyogoku has written "Goi no hikari" collected inNochi kōsetsu hyakumonogatari [ja].
...火の正体は五位鷺だったとされた。姥火とは、姥の死霊が変化した火の玉を意味する。根岸鎮衛の『耳嚢』(一八一一年成立)巻七には、五位鷺が幽霊に化けたという話がでてくる。これらの噂話の五位鷺は、おそらく鷺の仲間ではあるが標準和名のゴイサギであったとは限らないだろう。鷺がなぜ幽霊や人魂のたぐいの正体とされたかはわからない。
The wings of aged grey herons.. Their eyes shine..
青鷺（あをさぎ）の年を経（へ）しは、夜飛（よるとぶ）ときはかならず其羽（はね）ひかるもの也。目の光に映（えい）じ嘴（くちばし）とがりてすさまじきと也。
此鷺五位のくらひをさつかりし故にや夜に光りありてあたりを照せり
五位鷺が息をつくのを闇夜に見れば、火が青く光るようである。すべて鳥けだものの息（いき）は夜中（やちゆう）に光（ひか）る。猫の眼、虫の目、いずれも同（おな）じである。魚（いうお）の鱗を見て光物（ひかりもの）だと恐れ、朽ちた木を見て光明だと思う事はままあるならいである。すべて陰に生ずるものは陰気に応じて潤いを増し、陽に生ずるものは陽気に感じて潤いを添える事は、一切のものの常であり、殊更に驚くには足らない。昔、河内の国は内野という所に夜な夜な光物が現れ、見届けんとして出かけた者は...
上上吉第二番（ばん）目に、青鷺（あおさぎ）が仕内（しうち）。これは夜（よる）、往来（わうらい）の人を驚かすばかりなれど、さて気味の悪き光（ひか）り物（もの）なり。そのありさま、丈五尺ばかりの柱（はしら）のごときものに火燃（も）へて、後（あと）よりつい…これ、両（りゃう）の羽交（はがひ）いにてする芸なり。// 青鷺（あをさぎ）は首（くび）を縮めて、四角（かく）の柱（はしら）のごとくにして、上に火を燃やしたるよふに化（ば）け、人を驚（おどろ）かすばかりなり。これ、両の羽交いの光なり。
毎夜、青き火の見へる柳の大木あり。夜にいりて、そのもとへ行く者なし。ただ化け柳／＼とぞ言いける所の者、青き火の燃ゆるとも、今宵は篠突くごとくの雨ゆへ、その心もなからんと、たぶんその火のもとへ行きみれば、いつよりその火青みてものすごし。見るうちに、柳の大木、いつぱいに青く光りければ、かの男、そのま、倒れけり。これ、青鷺のなす技なり。
白鷺後者如赤火其跡如引白布白晝光物尤可謂奇特、雖有本文所見、於本朝無其例云々、又近國同時見云々再版：『吾妻鑑 下 校訂増補』、大観堂、1943年
初めは白鷺に似たり。後は赤火のごとし。その跡白布を引くがごとし。白晝の光物は、もつとも奇特といひつべし。