Division - Shidan (English spelling) division

A multi-disciplinary unit that brings together the main military professions (services) of the Army, which have comprehensive functions such as combat, supply, management, and medical care, and can carry out operations independently. It is the largest organized unit in the JGSDF, and is the basic operational unit that is responsible for the main operational front as the core unit of the regional army. It is usually commanded by a major general or lieutenant general (general in the JGSDF). The modern division system was established during the French Revolution, especially by Napoleon I, and became the basis of army organization around the world. The word division is also used in the navy and air force. The content of a division has changed over time and with the advancement of weapons, the form of warfare, and the national conditions, and today there are infantry divisions, mechanized infantry divisions, armored (tank) divisions, artillery divisions, airborne divisions, marine divisions, and air force divisions. The Japan Ground Self-Defense Force had long been structured around 13 divisions (12 infantry divisions, each based on three or four infantry regiments, and the 7th Armored Division, based on three tank regiments) and two mixed brigades, with a force of 180,000. However, in response to changes in the strategic environment such as the collapse of the Soviet Union and the post-Cold War era, since 1996, the force has been reorganized (reducing the number of personnel from 9,000 to approximately 7,700, including ready reserve personnel), and converted into brigades, resulting in a streamlined, compact, and efficient structure, and the force has gradually shifted to a 160,000-person force based on nine divisions and six brigades.

[Toshio Nakayama]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

戦闘・補給・管理・衛生など総合的な機能をもち、独立的に作戦を遂行しうる、陸軍の主要な職種（兵科）をひとまとめにした諸職種連合の部隊。陸上自衛隊では最大の編制部隊で、方面隊の基幹部隊として主要な作戦正面を担任する基本的な作戦部隊である。通常、少将ないし中将（陸上自衛隊では陸将）によって指揮される。近代的な師団制度は、フランス革命期、とりわけナポレオン1世によって確立され、世界の陸軍編制の基本となった。海空軍でも師団の語を用いることがある。師団の内容は、時代と兵器の進歩、戦争形態や国情などで変遷し、今日では歩兵師団、機械化歩兵師団、機甲（戦車）師団、砲兵師団、空挺(くうてい)師団、海兵師団、航空兵師団などがある。陸上自衛隊は13個師団（各3ないし4個普通科連隊基幹の12個歩兵師団と3個戦車連隊基幹の第7機甲師団）・2個混成団基幹の18万人体制を長くとってきたが、ソ連崩壊、ポスト冷戦などの戦略環境変化に対応し、1996年度（平成8年度）以降、師団改編（9000人から即応予備自衛官を含む約7700人へ定数減など）・旅団化などのスリム化、コンパクト化、効率化を実施し、9個師団・6個旅団基幹の16万人体制へと逐次移行している。

［中山敏雄］

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