Type 89 I - Go The was a medium tank used by the Imperial Japanese Army from 1932 to 1942 in combat operations of the Second Sino - Japanese War , at Khalkhin Gol against the Soviet Union , and in the Second World War . The Type 89B model was the world ' s first mass - produced diesel engine tank . 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 Panzer I s , 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 battles of Khalkhin Gol , against the Soviet Union , in 1939 . The code designation " I - Go " comes from the " katakana " letter [ イ ] for “ first ” and the " kanji " [ 号 ] for “ number ” . The designation is sometimes transliterated “ Yi - Go ” 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 for a lighter tank , with a nominal weight . The new design was modeled closely after the Vickers Medium C which had been bought by the Japanese Army in 1927 . By April 1928 , the new light tank design was finished and designated as the Type 89 . The prototype of the was completed in April 1929 . Later , the Type 89 was re - classified as a " medium tank " because the weight increased to over 10 tons due to several improvements . 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 . Production of the Type 89 began in 1931 and it soon became the main 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 . 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 ( L14 . 9 ) el angle of fire of −15 to + 20 degrees , AZ angle of fire of 20 degrees , muzzle velocity of , and could penetrate of 20 mm of armor at 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 bogie s , 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 searchlights 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 in a reverse L shape . Variants . The initial production model had a water - cooled 6 - cylinder 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 . 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 : reduced vulnerability to fire should the vehicle be hit or roll over ; better fuel economy ; greater torque at lower revolutions . 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 . The Type 89B Otsu version was the first mass - produced tank with a diesel engine . Combat history . The Type 89 was deployed for infantry support operations in the Second Sino - Japanese War . It served with Japanese infantry divisions before that , during the Japanese invasion of Manchuria ( September 1931 ) , and during the First Battle of Shanghai in 1932 , as part of the Imperial Japanese Navy ' s Special Naval Landing Force . The short - barreled 57 mm gun was effective at destroying machine gun nests and its armor , although thin , was enough to stop small arms fire . The relatively low speed of was not an issue in these types of operations . 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 . Battle of Khalkhin Gol . On the evening of 2 July 1939 , during the battle of Khalkhin Gol , the Japanese Army ' s 1st Tank Corps , commanded by Lt . General Yasuoka Masaomi , launched an offensive against the Soviet Union ' s 11th Tank and 7th Armored brigades . The 1st Tank Corps consisted of the 3rd and 4th Tank Regiment s ; of which the 3rd regiment consisted of 26 Type 89s , four Type 97 medium tanks , seven Type 94 tankette s , and four Type 97 tankettes , and the 4th regiment contained 35 Type 95s , eight Type 89s , and three Type 94 tankettes respectively . In this battle , the Type 97 medium tank was a newly fielded machine , and was primarily reserved for home units , as well as transitioning into Japanese Army forces stationed in China ( Manchuria ) . The 3rd Tank Regiment had , after charging through Soviet artillery barrages , successfully managed to overrun the Soviet motorized infantry , and took the high ground , which had been quickly abandoned by the Soviets . However , by 2100 hours , Soviet counter battery fire had begun pounding the newly taken position , and the 3rd Tank repositioned themselves behind the objective . The 4th Tank Regiment , which had become separated from the 3rd Tank Regiment , advanced upon an objective under the cover of a thunderstorm which masked their movements , but exposed the Soviet positions . The 4th Tank Regiment continued to advance , when suddenly a shift in the lightning flashes illuminated the advancing Japanese tanks , whereupon the Soviets immediately opened fire with anti - tank guns , heavy machine guns , and artillery . However , the range was so close , that the Soviet artillery could not depress their guns any lower , and the 4th Tank Regiment was ordered to charge at about 0020 hours ( 12 : 20 AM ) . Soviet shells passed wildly over the charging tanks as they penetrated over a thousand yards into the Soviet lines . Now isolated , and deep within the Soviet lines , the 4th Tank Regiment moved several thousands yards where they met up with Japanese infantry . The 4th Tank Regiment had expended 1 , 100 37 mm and 129 57 mm tank shells during the fight , as well as about 16 , 000 machine gun rounds . Of the approximate 73 light and medium Japanese tanks from both regiments committed to the offensive , 13 were damaged beyond repair by Soviet gunfire , about 14 others were repaired after major overhauls , and 17 tanks were repaired in the field . Soviet forces concluded that the 1st Tank Corps had penetrated the defenses of their 9th Armored Brigade and 149th Infantry Regiment and had reached Soviet artillery positions . Other Service . 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 they were a poor match for the American M4 Sherman . During the early stages of the First Indochina War , France set up an ad hoc unit of French and Japanese armour called the ' Commando Blindé du Cambodge ' from tanks left over from the Japanese invasion of French Indochina .