Type 89 I-Go Medium Tank

The Type 89 I-Go was a medium tank used by the Imperial Japanese Army from 1932 to 1942 in combat operations of the Second Sino-Japanese War, at Nomonhan against the Soviet Union, and the Second World War. The Type 89B model was the world's first diesel-engine tank built on a mass production scale. The tank was armed with a short-barrel 57 mm cannon for knocking out pillboxes and masonry fortifications, and proved effective in campaigns in Manchuria and China, as the Chinese National Revolutionary Army had only three tank battalions to oppose them, which consisted primarily of Vickers export models, German PzKpfw Is, and Italian CV33 tankettes. The Type 89 was a 1920s design medium tank, built to support the infantry, and thus lacked the armor or armament of 1940s generation allied armor; and was regarded as obsolete by the time of the Nomonhan Incident, against the Soviet Union, in 1939. The code designation "I-Go" comes from the katakana letter for “first” and the kanji for “number”. The designation is sometimes transliterated “Yi-Go”

Type 89 I-Go (Chi-Ro)
Place of origin	Empire of Japan
Production history
Designed	1928
Specifications
Weight	12.79 metric tons (14.10 short tons)
Length	5.73 m (18 ft 10 in)
Width	2.13 m (7 ft 0 in)
Height	2.56 m (8 ft 5 in)
Crew	4
Armor	6–17 mm (0.24–0.67 in)
Main armament	57 mm Type 90 gun 100 rounds
Secondary armament	2 x 6.5 mm Type 91 gun (hull, coaxial) 2,745 rounds
Engine	Mitsubishi A6120VD 6-cylinder air-cooled petrol diesel 120 hp (90 kW)/ 1800 rpm 14,300cc
Suspension	leaf spring
Operational range	170 km (110 mi)
Speed	26 km/h (16 mph)

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 0.85 metres (33 in) (L14.9) el angle of fire of −15 to +20 degrees, AZ angle of fire of 20 degrees, muzzle velocity of 380 m/s (1,200 ft/s), 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', an abbreviation of Nihonseikosho.

The Type 89 was driven through the rear drive sprocket and featured 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. Some vehicles were provided with two searchligths for night operations and Type 94 Mk 4 Hei (1934 model) radio communication device with range of 0.6 miles and weight of 198 lb, linked with a radio antenna of 29' 6" in a reverse L shape.