Type 89 I-Go

Infobox Weapon
name=Type 89 I-Go (Chi-Ro)


caption=A restored Type 89 I-Go at Tsuchiura GSDF Base open day
origin=flag|Empire of Japan
is_vehicle=yes
length=convert|5.73|m|ftin|abbr=on
width=convert|2.13|m|ftin|abbr=on
height=convert|2.56|m|ftin|abbr=on
weight=convert|12.79|metric ton|short ton|lk=on
suspension=leaf spring
speed=convert|26|km/h|mph|abbr=on
vehicle_range=convert|170|km|mi|abbr=on
primary_armament=57 mm Type 90 gun
100 rounds
secondary_armament=2 x 6.5 mm Type 91 gun
(hull, coaxial)
2,745 rounds
armour=convert|6|to(-)|17|mm|in|abbr=on
engine=Mitsubishi A6120VD 6-cylinder air-cooled petrol diesel
engine_power=120 hp (90 kW)
pw_ratio=
crew=4

The nihongo|Type 89 I-Go|八九式中戦車　イ号|Hachikyūshiki chūsensha I-gō was a medium tank used by the Imperial Japanese Army from 1932 to 1942 in combat operations of the Second Sino-Japanese War and the Second World War. The tank was armed with a short-barrel 57-mm cannon for knocking out pillboxes and stone and masonry fortifications, and proved effective in campaigns in Manchuria and China, as the Chinese National Revolutionary Army had very few tanks or anti-tank weapons to oppose them. However, the Type 89 lacked the armor or armament of contemporary western tanks, and was regarded as obsolete by the start of World War II. Foss. The Great Book of Tanks ] The code designation "I-Go" comes from the "katakana" letter [イ] for “first” and the "kanji" [号] for “number”. [http://www.historyofwar.org/articles/weapons_japanese_tank_designations_WWII.html ] The designation is sometimes transliterated “Yi-Go” [Zaloga, "Japanese Tanks 1939–45", p. 90.]

History and development

The Type 89 evolved from Japan's first domestic light tank project initiated by the Japanese Army's Osaka Technical Arsenal in 1925. However, the growing weight of the initial prototype and its low speed did not impress the Imperial Japanese Army General Staff Office, and a new requirement was issued to for a lighter tank, with a nominal convert|10|short ton|metric ton|sing=on weight.

The new design was modeled closely after the Vickers Medium C tanks, several samples of which had been obtained by the Japanese Army in 1927. By April 1929, the new light tank design was finished and designated as the Type 89. Later, the Type 89 was re-classified as a "medium tank" because the weight increased to over 10 tons due to several improvements. [Zaloga, "Japanese Tanks 1939–45", p. 90.]

As the Army's Sagami Arsenal lacked the capacity for mass production, a contract was awarded to Mitsubishi Heavy Industries, which built a new factory next to the Sagami Arsenal specifically to produce this model. [Zaloga, "Japanese Tanks 1939–45", p. 90.] Production of the Type 89 began in 1931 and it soon became the main battle tank of the Imperial Japanese Army.

Although the Type 89 was well regarded by the Japanese army, there were several small problems to be rectified, notably a gap under the mantlet on early models that allowed rifle fire to enter the turret. Work continued on improving the Type 89 after the production started, and as a result many variants were developed. Foss. The Great Book of Tanks ]

Design

The Type 89 required a crew of four (commander/gunner, loader, driver and hull gunner).

The design of the Type 89 was relatively conventional with a forward-mounted gun turret carrying the main armament, a Type 90 57 mm gun that was complemented by two Type 91 6.5 mm machine guns. One was placed in the turret and pointed towards the rear, a practice followed with most Japanese tanks, and one was located in the hull. The Type 90 57 mm Tank Gun had a barrel length of convert|0.85|m|in (L14.9) el angle of fire of −15 to +20 degrees, AZ angle of fire of 20 degrees, muzzle velocity of convert|380|m/s|ft/s|abbr=on, and penetration of 20 mm/500 m (0.8 in/550 yd).

Rather than using iron armor, as on the earlier Type 87, the designers chose to use steel plate armor developed by the Nihon Seikosho Company (JSW). The type of armor was referred to as 'Niseko steel', abbreviated as Nihonseikosho.

The Type 89 was driven through the rear drive sprocket; with nine bogies, mounted in pairs on each side, with the forward bogie on an independent suspension. Five smaller return wheels were mounted along a girder.

Variants

*nihongo|Type 89A I-Go Kō|八九式中戦車（甲型）|The initial production model had a gasoline engine and mounted a machine gun on the right side of the hull. This design could only attain 15.5 km/h, and was also limited by the severe winter climate in northern China. A total of 220 units were produced.

*nihongo|Type 89B I-Go Otsu|八九式中戦車（乙型）|The "Ko" was superseded in production from 1934 by the model "Otsu" with an air-cooled Mitsubishi A6120VD 120 hp diesel engine. The improved model had a new gun turret design complete with a cupola for the commander, and with the machine gun relocated to the left side of the hull. The multiple armor plates of the front hull were replaced by a single shallow-sloped frontal armor plate which provided more protection for the driver. However, the major difference between the versions was the Mitsubishi air-cooled 6-cylinder diesel engine, which had several advantages, notably reduced vulnerability to fire and better fuel economy. A diesel engine was also preferred by the Japanese Army because more diesel fuel than gasoline could be produced per barrel of oil. A total of 189 "Otsu" units were produced. It is noteworthy that the Type 89B Otsu version was the first diesel-powered tank to be mass-produced in the world. [Zaloga, "Japanese Tanks 1939–45", p. 90.]

Combat history

The Type 89 was deployed for infantry support operations in the Second Sino-Japanese War. It was present with Japanese infantry divisions during the Manchurian Incident and also during the First Battle of Shanghai in 1932 as part of the Imperial Japanese Navy Special Naval Landing Force. The short-barreled 57 mm gun was effective at destroying machine gun nests and its convert|15|mm|in|abbr=on armor, although thin, was enough to stop small arms fire. The relatively low speed of convert|25|km/h|mph|abbr=on was not an issue in these types of operations. [ [http://www3.plala.or.jp/takihome/develop.html Taki's Imperial Japanese Army] ]

The following year, the Japanese Army formed its first independent armor force, by creating three regiments armed with the Type 89 I-Go, each consisting of two companies with ten tanks each. Three more regiments were formed in 1934.

Type 89s were used widely in various campaigns throughout China after 1937. They were also used against Soviet forces at the Battle of Nomonhan in the Soviet-Japanese War of 1939.

By 1942 the Type 89 was gradually being withdrawn from front-line combat service, but many units saw action in the Battle of the Philippines, Battle of Malaya, and Burma campaign, and continued to be used in China. They were also often used in static defense positions in the Japanese-occupied islands of the Netherlands East Indies and in the South Pacific Mandate, but with their weak armor and small main gun were a poor match for the American M4 Sherman.Foss. The Great Book of Tanks ]

WWII Japanese units equipped with the Type 89 Tank

*1st Independent Mixed Brigade
*3rd Tank Regiment
*4th Tank Regiment
*7th Tank Regiment
*2nd Independent Tank Company
*1st Special Tank Company
*1st Tank Battalion
*2nd Tank Battalion
*5th Tank Battalion
*Special Tank Company of China Detachment Tank Unit
*7th Tank Regiment
*8th Independent Tank Company
*9th Independent Tank Company
*2nd Tank Division

urvivors

One surviving Type 89 I-Go is on display at the United States Army Ordnance Museum at Aberdeen, Maryland (where it is labelled as a "Type 89 Chi-Ro"). Another is located at the Japanese Ground Self-Defense Force base at Tsuchiura, Ibaraki in Japan.

References

*cite book
last = Foss
first = Christopher
year = 2003
title = Great Book of Tanks: The World's Most Important Tanks from World War I to the Present Day
publisher = Zenith Press
location =
id = ISBN 0760314756
*cite book
last = Foss
first = Christopher
year = 2003
title = Tanks: The 500
publisher = Crestline
location =
id = ISBN 0760315000
*cite book
last = Zaloga
first = Steven J.
year = 2007
title = Japanese Tanks 1939–45
publisher = Osprey
location =
id = ISBN 1-84603-091-8

External links

* [http://www.wwiivehicles.com/japan/tanks-medium/type-89-chi-ro.asp WWII vehicles]
*OnWar.com: [http://www.onwar.com/tanks/japan/data/t89achiro.htm Type 89A] [http://www.onwar.com/tanks/japan/data/t89bchiro.htm Type 89B]
* [http://www.tanksinworldwar2.com/japan.aspx Photo gallery at military.cz]
* [http://science.howstuffworks.com/type-89-chi-ro-medium-tank.htm Japanese Type 89 CHI-RO Medium Tank] at howstuffworks.com
* [http://www3.plala.or.jp/takihome/develop.html Taki's Imperial Japanese Army Page]

Notes