Imperial Japanese Army

Imperial Japanese Army
Dai-Nippon Teikoku Rikugun
War flag of the Imperial Japanese Army (1868-1945).svg
The ensign of the Imperial Japanese Army
Country Empire of Japan
Allegiance Emperor of Japan
RoleMilitary ground force
Size6,095,000 men at peak
Ceremonial chief

The Imperial Japanese Army (IJA; 大日本帝國陸軍 Dai-Nippon Teikoku Rikugun; "Army of the Greater Japanese Empire") was the official ground-based armed force of the Empire of Japan from 1868 to 1945. It was controlled by the Imperial Japanese Army General Staff Office and the Ministry of the Army, both of which were nominally subordinate to the Emperor of Japan as supreme commander of the army and the navy. Later an Inspectorate General of Aviation became the third agency with oversight of the army. During wartime or national emergencies, the nominal command functions of the emperor would be centralized in an Imperial General Headquarters (IGHQ), an ad-hoc body consisting of the chief and vice chief of the Army General Staff, the Minister of the Army, the chief and vice chief of the Naval General Staff, the Inspector General of Aviation, and the Inspector General of Military Training.

Origins (1868–1871)

In the mid-19th century, Japan had no unified national army and the country was made up of feudal domains (han) with the Tokugawa shogunate (bakufu) in overall control, which had ruled Japan since 1603. The bakufu army, although large force, was only one among others, and bakufu efforts to control the nation depended upon the cooperation of its vassals' armies.[1] The opening of the country after two centuries of seclusion subsequently led to the Meiji Restoration and the Boshin War in 1868. The domains of Satsuma and Chōshū came to dominate the coalition against the shogunate.

Boshin war

Ukiyo-E, depicting the retreat of shogunate forces in front of the Imperial Army (Kangun). Yodo Castle is shown in the background.

On 27 January 1868, tensions between the shogunate and imperial sides came to a head when Tokugawa Yoshinobu marched on Kyoto, accompanied by a 15,000-strong force consisting of troops that had been trained by French military advisers. They were opposed by 5,000 troops from the Satsuma, Chōshū, and Tosa domains. At the two road junctions of Toba and Fushimi just south of Kyoto, the two forces clashed. On the second day, an Imperial banner was given to the defending troops and a relative of the Emperor, Ninnajinomiya Yoshiaki, was named nominal commander in chief, in effect making the pro-imperial forces officially an Imperial army (官軍, kangun).[2] The bafuku forces eventually retreated to Osaka, with the remaining forces ordered to retreat to Edo. Yoshinobu and his closest advisors left for Edo by ship.[3] The encounter at Toba–Fushimi between the imperial and shogunate forces marked the beginning of the conflict. With the court in Kyoto firmly behind the Satsuma-Chōshū-Tosa coalition, other domains that were sympathetic to the cause—such as Tottori (Inaba), Aki (Hiroshima), and Hizen (Saga)—emerged to take a more active role in military operations.[4] Western domains that had either supported the shogunate or remained neutral also quickly announced their support of the restoration movement.[4]

The nascent Meiji state required a new military command for its operations against the shogunate. In 1868, the "Imperial Army" being just a loose amalgam of domain armies, the government created four military divisions: the Tōkaidō, Tōsandō, San'indō, and Hokurikudō, each of which was named for a major highway.[5] Overseeing these four armies was a new high command, the Eastern Expeditionary High Command (Tōsei daisō tokufu), whose nominal head was prince Arisugawa-no-miya, with two court nobles as senior staff officers.[5] This connected the loose assembly of domain forces with the imperial court, which was the only national institution in a still unformed nation-state.[5] The army continually emphasized its link with the imperial court: firstly, to legitimize its cause; secondly, to brand enemies of the imperial government as enemies of the court and traitors; and, lastly, to gain popular support.[6] To supply food, weapons, and other supplies for the campaign, the imperial government established logistical relay stations along three major highways. These small depots held stockpiled material supplied by local pro-government domains, or confiscated from the bafuku and others opposing the imperial government. Local villagers were routinely impressed as porters to move and deliver supplies between the depots and frontline units.[6]

Struggles to form a centralized army

Initially, the new army fought under makeshift arrangements, with unclear channels of command and control and no reliable recruiting base.[6] Although fighting for the imperial cause, many of the units were loyal to their domains rather than the imperial court. In March 1869, the imperial government created various administrative offices, including a military branch; and in the following month organized an imperial bodyguard of 400 to 500, which consisted of Satsuma and Chōshū troops strengthened by veterans of the encounter at Toba–Fushimi, as well as yeoman and masterless samurai from various domains.[6] The imperial court told the domains to restrict the size of their local armies and to contribute to funding a national officers' training school in Kyoto.[6] However, within a few months the government disbanded both the military branch and the imperial bodyguard: the former was ineffective while the latter lacked modern weaponry and equipment. To replace them, two new organizations were created. One was the military affairs directorate which was composed of two bureaus, one for the army and one for the navy. The directorate drafted an army from troop contributions from each domain proportional to each domain's annual rice production (koku). This conscript army (chōheigun) integrated samurai and commoners from various domains into its ranks.[6] As the war continued, the military affairs directorate expected to raise troops from the wealthier domains and, in June, the organization of the army was fixed, where each domain was required to send ten men for each 10,000 koku of rice produced. However, this policy put the imperial government in direct competition with the domains for military recruitment, which was not rectified until April 1868, when the government banned the domains from enlisting troops. Consequently, the quota system never fully worked as intended and was abolished the following year.[6]

The Imperial forces encountered numerous difficulties during the war, especially during the campaign in Eastern Japan. Headquarters in faraway Kyoto often proposed plans at odds with the local conditions, which led to tensions with officers in the field, who in many cases ignored centralized direction in favor of unilateral action.[7] The army lacked a strong central staff that was capable of enforcing orders. Consequently, military units were at the mercy of individual commanders' leadership and direction. This was not helped by the absence of a unified tactical doctrine, which left units to fight according to the tactics favored by their respective commanders. There was increased resentment by many lower ranked commanders as senior army positions were monopolized by the nobility together with samurai from Chōshū and Satsuma.[7] The use of commoners within the new army created resentment among the samurai class. Although the nascent Meiji government achieved military success, the war left a residue of disgruntled warriors and marginalized commoners, together with a torn social fabric.[8]