The Empire of Japan went through a period of militarization following the end of World War 1. She consistently bred military-minded civilians and began upgrading her weapon inventories to the point that she was ready to go to war by the 1930s. Resources were high on her agenda and the nearby regions were primed for the taking. All-out war would eventually find her and her people to which she required the vast output of weaponry and war-making capabilities as much as the next world power.
At this point in history, Japan was never to be regarded as a tank-producing powerhouse to the rest of the globe. Her designs were usually copies of existing systems or those purchased on foreign orders. In 1925, Japanese authorities enacted the indigenous "Number 1 Tank Project" with the hopes of designing and producing a capable infantry light tank. As an infantry light tank, the type would showcase strong cross-country performance qualities, reliability and firepower suitable for tackling enemy troop concentrations and fortified structures. It would operate in conjunction with foot soldiers in much the same way as British tank tactics were laid out at the time (the British divided their tanks into "cruiser" types built on speed and "infantry" tanks built on firepower).
The Number 1 Tank design was developed by Japanese engineers but it was soon found to be too heavy for its intended "light tank" role. Additionally, engine problems crept into the arrangement and forced a different solution. As such, engineers looked to the British Vickers Medium C light tank which had just recently been purchased by the Empire of Japan in limited quantities. The design was thoroughly examined and its best assets were adopted into a new Japanese design to suit the requirements of the Imperial Japanese Army (IJA). Formal evaluations of the system ensued in 1929 and a procurement contract was agreed upon. The resulting tank became the Type 89 "Chi-Ro" with the "89" numeric designation stemming from the Japanese calendar year of "2589" - or 1929. Production began in 1931. Her weight had grown to 12.8 tons and she was no longer considered a light tank but was classified by the IJA as a "Medium Tank".
The Chi-Ro was of a conventional design and layout for this period. She was crewed by four personnel in cramped conditions and was operated by a commander, gunner, bow-gunner and driver. The bow-gunner and driver maintained positions at the front hull while the commander and gunner resided in the forward-set traversing turret. The engine was fitted to the rear, noted by a right-rear mounted exhaust cylinder, as was the all-important drive sprocket. The track idler was located at the front and nine road wheels were set low along the track systems. No fewer than four track return rollers were present along the upper portion of the track sides. The design maintained a pronounced "nose-up" appearance when at rest and this served the type well in traversing uneven terrains. The turret featured slanted armor plating for minimal ballistics protection as well as a circular commander's cupola. Main armament centered around a 57mm main gun and some 100 projectiles were carried aboard, all of the High-Explosive (HE) variety. The main armament was supplemented by a pair of 6.5mm machine guns for anti-infantry defense. One was set in a rear-facing position at the rear of the turret while the other was in a bow-mounted fitting. The rear-facing machine gun was rather unconventional by Western standards but was commonplace in several Japanese and Soviet tank designs of the time - serving to protect the critical rear facing of the tank. The bow-mounted machine gun was common practice around the globe concerning tank design and offered from forward protection against infantry where the main gun proved too excessive. Power was supplied by a Mitsubishi gasoline engine (later diesel). The Type 89 was only able to make 15.5 miles per hour in ideal conditions and fielded a range out to 99 miles.
Once in service, the few operational Type 89s proved excellent for their intended role. Up to now, they fought in select attachments and were not a direct force of the IJA per se. Considering one of her first combat actions was against the lesser-equipped forces of China in Shanghai in 1932, the Type 89 was a stellar performer. The Chinese military lacked much in the way of tank-stopping firepower and this allowed the Type 89 to shine in its infantry support role. The wide open ranges of the Chinese countryside also played well into the Type 89s reliable design and strong suspension system. Her 57mm main gun was up to the challenge of the day and her armor protection was adequate against even 37mm anti-tank projectiles utilized by the enemy. The Type 89 was formally adopted by the IJA by 1933 to which at least three full regiments were formed.
In 1934, a new Mitsubishi diesel engine of 115 horsepower was unveiled along Type 89 production lines necessitating the differentiating designations of "Type 89A" and "Type 89B" to be assigned, the latter being the diesel fueled-types. Diesel fuel engines provided a better match for the resource-strapped Japanese and were much more efficient in certain combat environments. In addition to the engine upgrade, the Type 89 had her glacis plate redesigned for better inherent ballistics protection and a new gun mantlet was fitted over the 57mm cannon for improved protection. The commander's position was installed with a new, more efficient cupola hatch arrangement and machine gun ports were further protected.
The Japanese Army struck across China in 1937 and continued to proved themselves against lesser foes. It was not until the tank faced off against the Soviet Army in 1939 at the Mongolian border that its weaknesses shown through. The Japanese offensive was utterly repelled and ultimately forced a loose truce between the two parties. These actions showcased the need to upgrade the Type 89 with an all-new type and further work inevitably led to the development and production of its successor - the Type 97.
Regardless, the Type 89 was still available in numbers and was used throughout the future Pacific campaigns involving the Philippines and much of Southeast Asia (Burma and Malaya). As it excelled in open-field warfare, it also surprisingly succeeded in the cramped jungle setting, continuing its streak of excellence for the IJA. As fronts for the IJA began to settle somewhat, the Type 89 found a second wind as a fixed defensive armament to secure key positions - her 57mm main gun still a proper choice for dealing with enemy infantry collections and soft fortifications. As a combat tank, however, she was deemed wholly obsolete by 1942 and her replacement was coming online.
With the American entry into World War 2 following the Japanese attack on Pearl Harbor on December 7th, 1941, the Type 89 would meet its untimely match against the better armored and armed US medium tanks, particularly the M4 Sherman. Additionally, American infantry sported highly-capable anti-tank weapons when compared to their Chinese counterparts and these weapons could pierce the armor of the Type 89 with relative ease. As such, its days as a frontline tank were officially over despite the type continually being encountered into 1944.
Throughout the early portions of the Japanese expansion across the Pacific, the Type 89 was a key battlefield operator. Her limited design scope coupled with emerging battlefield technologies worldwide ultimately led her to the wayside but she soldiered on where needed. The Empire of Japan ultimately capitulated in August of 1945 and formally surrendered the following month, bringing an end to her empirical days. Ultimately, the Empire of Japan would never be regarded as a top tank designer or producer in the war for she would and could never match the developments and wartime production of her contemporaries - especially that of the United States, her key opponent in the region.