Hachijojima

It belongs to the Hachijo Branch Office of Tokyo and, together with Hachijokojima (uninhabited), about 4 kilometers (hereafter referred to as "Kilo") to the west, forms the town of Hachijo. It is a volcanic island in the southern Izu Islands, about 290 kilometers south of Tokyo. It is the second largest island in the archipelago after Oshima. It is gourd-shaped, with the two volcanoes Nishiyama in the northwest and Higashiyama in the southeast joining together, with a long axis of about 14 kilometers, a circumference of about 59 kilometers, an area of ​​69.52 square kilometers, and a population of 8,318 (2009). It is part of Fuji-Hakone-Izu National Park and is a tourist destination rich in tropical atmosphere with a subtropical climate.

Higashiyama (701m), also known as Miharayama, is a multi-layered composite volcano with a circular caldera about 4km in diameter. Both the pre-caldera and post-caldera volcanoes are stratovolcanoes of basalt and andesite, the latter of which has cinder cones in its summit crater and on its flanks. Higashiyama has no record of eruptions, is undergoing dissection, and its activity appears to have occurred in the Pleistocene (Pleistocene). Nishiyama (854m), also known as Hachijo Fuji, is the highest peak in the Izu Islands and is a basaltic strato-conical volcano with a wide base. It is a dual-layered active volcano born in the Holocene (Pleistocene), with a small crater cone in its summit crater about 400m in diameter. Starting in 1487 (Chokyo 1), there are five recorded eruptions by 1605 (Keicho 10), with eruptions occurring from the summit, the mountainside, and the nearby seabed. The area between Higashiyama and Nishiyama is gently sloping or flat, but the coast of Higashiyama and the northwest coast of Nishiyama form steep cliffs. Higashiyama is blessed with water due to the overlapping mountains, deep valleys, and thick topsoil, and there are water sources everywhere, which are used for drinking water, irrigation water, and power generation water, and it is the only place in the Izu Islands where there are rice paddies. Surrounding Higashiyama, the settlements of Mitsune and Ogago in the northern lowlands known as Sakashita, and Kashidate, Nakanogo, and Sueyoshi in the southern hillside known as Sakagami, are located on springs. The climate is hot and humid subtropical, with an average annual temperature of 17.8°C, a minimum temperature of 10.1°C (January), and an average annual precipitation of 3,202.4 mm (average value from 1981 to 2010). Plants flourish, and about 80% of the island is covered with evergreen trees such as chinquapin, sakaki, camellia, and tabu.

The island was named Hachirojima after the legend of Chinzei Hachiro Tametomo (Minamoto no Tametomo). The island's history is told through its high stone windbreak walls, raised grain warehouses, steeply sloping thatched roofs, gravestones of exiles such as Ukita Hideie, and abandoned graves of castaways. It has long been a base for Pacific fishing, and there are good fishing grounds for bonito and flying fish nearby. Although there are few ports, there are two ports, Kamiminato to the east and Yaene to the west, which have been developed under the Remote Islands Development Act, and regular ferries operate from Tokyo's Takeshiba Pier. Hachijojima Airport, located at the southeastern foot of Nishiyama, also attracts many tourists on regular flights from Haneda Airport. It is known as a producer of raw silk, silk and yellow Hachijo, named after the islands' names, Itoshima, Nyogojima and Hachijojima. In addition to self-sufficiency crops such as rice, wheat and sweet potatoes, in recent years, the cultivation of tropical horticultural crops, mainly ornamental plants and bulbs, has been thriving, and a wide variety of plants, including phoenix, freesia, pineapple, rubber and other aromatic plants, are exported. Tourism development is progressing with paved roads, hot spring drilling, hotel construction and tourist botanical gardens, and it is a sister island of Maui, Hawaii, USA, which has many similarities with it. There are many folk performing arts such as Ushizumou, Kashidate Dance (National Intangible Folk Cultural Property), and Taiko Bayashi, as well as historical and historic sites such as the remains of the island office, which are designated as Tokyo's cultural property, the Fukuyaheya Shiki (Kashidate Dance performance), and the Nagatoro Mansion (historical documents collection).

In addition, the 69 volumes of "Hachijo Jikki" written by Kondo Tomizo, an exile from the end of the Edo period, are a valuable record that conveys the life and customs of the island.

[Kikuchi Masao and Suwa Akira]

"Hachijo Jikki" by Kondo Tomizo, 7 volumes (1964-1976, Ryokuchisha)" ▽ "Hachijojima Chronicle" (1973, Hachijo Town) ▽ "Izu Islands and Ogasawara Islands" (1984, Tokyo Islands Towns and Villages Association)"

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

東京都八丈支庁に属し、西約4キロメートル（以下、キロと略す）の八丈小島（無人）とともに八丈町をなす。東京の南約290キロで、伊豆諸島南部にある火山島。同諸島では大島に次いで大きい。北西の西山、南東の東山の両火山が接合したひょうたん形で、長軸約14キロ、周囲約59キロ、面積69.52平方キロ、人口8318（2009）。富士箱根伊豆国立公園に含まれ、亜熱帯気候の南国情緒豊かな観光地である。

　東山（701メートル）は三原山ともよばれ、径約4キロの円形のカルデラをもつ多重式複成火山である。先カルデラ火山も後カルデラ火山も玄武岩、安山岩の成層火山で、後者の山頂火口内や山腹には噴石丘がある。東山は噴火記録がなく、開析が進んでおり、その活動は更新世（洪積世）らしい。西山（854メートル）は八丈富士ともよばれ、伊豆諸島中の最高峰で、広い裾野(すその)を引く玄武岩の成層・円錐(えんすい)火山である。完新世（沖積世）に生まれた二重式の活火山で、径約400メートルの山頂火口内に小火口丘がある。1487年（長享1）を皮切りに、1605年（慶長10）までに5回の噴火記録があり、山頂、山腹や付近海底からも噴火した。東山と西山の中間は、なだらかな傾斜地ないし平坦(へいたん)地であるが、東山の沿岸と西山の北西側沿岸は急崖(きゅうがい)をなしている。東山は山々が重複し、谷が深く、表土が厚いために水に恵まれ、随所に水源があり、飲料水、灌漑(かんがい)用水、発電用水に利用され、伊豆諸島中ここだけに水田がある。東山を囲み、坂下とよばれる北側低地の三根(みつね)、大賀郷(おおがごう)、坂上とよばれる南側山手の樫立(かしだて)、中之郷(なかのごう)、末吉(すえよし)の諸集落が湧水(ゆうすい)地に立地している。気候は高温多湿の亜熱帯性で、年平均気温17.8℃、最低気温10.1℃（1月）、降水量は年3202.4ミリメートルもあり（1981～2010年の平均値）、植物がよく繁茂し、島の約80％がシイ、サカキ、ツバキ、タブなどの常緑樹で覆われている。

　鎮西八郎為朝(ちんぜいはちろうためとも)（源為朝）の伝説にちなみ、八郎島とよばれたのが地名の由来という。防風用の高い玉石垣、高床式の穀物庫（高倉）、急傾斜のかや葺(ぶ)き屋根、宇喜多秀家(うきたひでいえ)などの流人の墓石、漂流者の無縁塚など、島の歴史を物語る景観が随所に残されている。古くから太平洋漁業の基地で、付近にもカツオ、トビウオなどの好漁場がある。港湾は乏しいが、東に神湊(かみみなと)、西に八重根(やえね)の両港があり、離島振興法で整備されており、東京の竹芝桟橋から定期船が就航している。また、西山の南東麓(なんとうろく)の八丈島空港へも、羽田空港から多数の観光客が定期便で来遊する。綜嶼(いとしま)、女護(にょご)島、八丈島などの呼称にちなむ生糸、絹、黄八丈(きはちじょう)の生産地として知られる。また、米、麦、サツマイモなどの自給作物のほか、近年、観葉植物、球根類を主とする熱帯園芸作物栽培も盛んで、フェニックス、フリージア、パイナップル、ゴム、そのほか香料植物など多彩で、移出されている。舗装道路、温泉ボーリング、ホテル建設、観光植物園造成など、観光開発が進んでおり、類似点の多いアメリカ、ハワイ州のマウイ島と姉妹島になっている。牛角力(うしずもう)、樫立踊（国選択無形民俗文化財）、太鼓(たいこ)ばやしなどの民俗芸能や、東京都文化財に指定されている島役所跡、服部屋敷（樫立踊実演）、長戸路(ながとろ)屋敷（古文書所蔵）などの史跡や旧跡も多い。

　なお、幕末の流人近藤富蔵著『八丈実記』69巻は、島の生活、風俗を伝える貴重な記録である。

［菊池万雄・諏訪　彰］

『近藤富蔵著『八丈実記』全7巻（1964～1976・緑地社）』▽『『八丈島誌』（1973・八丈町）』▽『『伊豆諸島・小笠原諸島』（1984・東京都島嶼町村会）』

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