We encountered a few interesting placename etymologies on our recent travels in Japan.
五毛 Gomou ‘Five Hairs’ < 胡麻生 Gomau ‘Sesame Growth’ - I spent my high school years in a dormitory atop Nagamine-dai (‘longridge-heights’) below towering Maya-san in Nada-ku (‘opensea-ward’), Kobe. The neighborhood at the base of our hillside was called Gomou, written as if it meant ‘Five Hairs’ (五毛). I never paid attention to how it got its odd name until I went back by there on this trip. According to its short Wikipedia article, the name Gomou originated as Gomau (胡麻生 ‘sesame-grow’) because the area was not suitable for paddy fields, so the farmers grew sesame instead. (The city in Gunma Prefecture called Kiryu—桐生 < kiri-u ‘Paulownia-grow’—must have got its name for similar reasons.) Over time, the pronunciation of Gomau changed to Gomou, the sesame fields disappeared under dense urban growth, and someone devised entirely new kanji, with no etymological continuity at all, to match its new pronunciation.
戸隠 Togakushi ‘door-hiding’ - In northern Nagano Prefecture, we explored the lovely mountain forests of Togakushi, site of an extensive old Shinto Shrine complex that also served as training grounds for ninja. Togakushi used to be called Togakure, using the shape of the verb kakureru ‘hide’ that appears in the name of the game kakurembo ‘hide-and-seek’. One of the many schools of ninja tradition is called Togakure-ryu. We looked for ninjas, but of course they remained well hidden. (Bears, however, had left many signs of their presence, including claw marks on tree trunks and chewed up patches of their favorite 水芭蕉 mizubashou ‘skunk cabbage’.)
神居木 Kamoigi ‘god-dwell-tree’ - While walking a woodsy stretch of the old Nakasendō (中山道 ‘Central Mountain Route’) between Magomejuku in Gifu-ken and Tsumagojuku in Nagano-ken, we came across signage about some old, famous sawara cypress trees, one of which had acquired the name 神居木 Kamoigi ‘god-dwell-tree’ because a god supposedly rested in it long ago. I wonder where the -o- came from. The morpheme written 木 ‘tree’ is pronounced -ki in Tochinoki ‘horsechestnut-POSS-tree’ but -gi in the prefecture name Tochigi ‘horsechestnut-tree’. In native Japanese placenames, the kanji 神 ‘god’ is most often pronounced either kami- as in Kamiyama 神山 ‘god-mountain’ or kan- as in Kanda 神田 ‘god-paddy’, but it is also pronounced kō- in Kōbe 神戸 ‘god-door’. The kanji 上 ‘upper’, which appears in many placenames old and new, shows similar variation, ranging from 上山 Kamiyama ‘upper-mountain’ to the ancient province names 上総 Kazusa (now Chiba Prefecture) and 上野 Kōzuke (originally 上毛野, now Gunma Prefecture). In such cases, the long -ō- replaces the earlier -am- or -an-; it does not follow after kam- or kan-. So I suspect the -o- somehow comes from the 居 i(ru) ‘reside, dwell’ (as in 居酒屋 izakaya lit. ‘dwell-sake-shop’), which is pronounced o(ru) in several regional dialects of central and southwestern Honshu. In fact, I wonder if the earlier name for the tree might have been pronounced Kami-o(ru)-gi ‘god-dwell-tree’.