Chikuma Mountains - Chikumasanchi

A mountain range running north to south through central Nagano Prefecture, it separates the Chikuma River basin from the Azusa River and Takase River basins. The northern part is bordered by the Susobanagawa River with the Togakushi volcanic group, and the southern part is divided by the Wada Pass with the Tateshina and Yatsugatake volcanic mountain ranges. Most of the area is hilly, ranging from 1,200 to 1,500 meters, with the southern part being higher than the southern part, including mountains such as Hachibuseyama (1,929 meters), Utsukushigahara, and Takeshimine (1,973 meters), and the elevation decreases as you move north. The Sai River crosses the northern part as a leading river, forming a deep eroded valley. It is part of the Yatsugatake-Chushin Highlands Quasi-National Park.

The Chikuma Mountains have long been a major transportation barrier, and the Hofukuji Pass on the ancient to medieval Tosando Road, which connected the Ueda/Nagano Basin with the Matsumoto/Suwa Basin, and the Wada Pass on the modern Nakasendo Road were known as difficult passes. Construction of the Misayama and Shinwada road tunnels, and the Kamuriki Tunnel on the JR Shinonoi Line were also difficult challenges.

[Hiroyoshi Kobayashi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

長野県中央部を南北に走る山地で、千曲(ちくま)川流域と梓(あずさ)川・高瀬(たかせ)川流域を分ける。北部は裾花(すそばな)川によって戸隠(とがくし)火山群と境し、南部は和田峠によって蓼科(たてしな)、八ヶ岳(やつがたけ)火山連峰と画される。1200～1500メートルの丘陵性地形が大部分で、標高は南が高く、鉢伏山(はちぶせやま)（1929メートル）、美ヶ原(うつくしがはら)、武石峰(たけしみね)（1973メートル）などの山々があり、北方へいくにしたがって高度を減じている。北部を犀(さい)川が先行性河川として横断し、深い侵食谷を形成する。八ヶ岳中信高原国定公園の一部。

　筑摩山地は長く交通上の大きな障壁をなし、上田・長野盆地と松本・諏訪(すわ)盆地を結ぶ古代から中世の東山道(とうさんどう)保福寺峠(ほふくじとうげ)、近世の中山道(なかせんどう)和田峠は難所として知られ、三才山(みさやま)、新和田の道路トンネル、JR篠ノ井(しののい)線の冠着(かむりき)トンネルなども難工事であった。

［小林寛義］

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