Saturday, 23 January 2016

World of Tanks History Section: Japanese Tank Building

In the middle of the 19th century, Japan began the Meiji Restoration. After a few decades, the backwards island nation became a sovereign empire with a powerful army and navy. Japan also maintained very aggressive external policies. Defeating China in 1895 and the Russian Empire in 1905, the Land of the Rising Sun obtained dominance over the Far East.

When tanks appeared in 1916, they piqued the interest of Japanese military minds. Colonel Hoshino wrote: "No country can consider itself protected if it does not have powerful artillery, modern tanks, and aircraft." Soon, a special committee of the Imperial High Command was established, tasked with creating an armoured force in Japan. In 1921-1927, Japan actively acquired foreign vehicles. These were British Vickers MkC, MkA Whippet, French Renault FT, and others.

In 1930, Japan purchased French Renault NC27 tanks. They were used by the Japanese army under the index NC27 Otsu until 1940. The Japanese version differed from the French in its improved armour and armament. Some of these vehicles also used domestic diesel engines, although it is not known how many tanks were equipped with them.

In the middle of the 1920s, Japan  took designing its own tanks seriously. The Osaka Arsenal became an important center for tank designers. A large series of private and government owned factories were converted to produce tanks. Among them, Mitsubishi was the largest, also producing automobiles and armoured cars.

The first Japanese tank was indexed #1 Chi-I. The Osaka Arsenal developed it in 1927. The tank had two turrets, armed with either a 57 or a 70 mm gun, and two machine guns. Due to its weak engine, the tank performed poorly, and had a very low off-road speed. It did not make it to mass production.

The light Type 87 tank was developed in parallel with the Chi-I. It also did not reach mass production; the military considered its armament too weak and armour too thin. However, one cannot say that the engineers wasted their time: using experience from the Type 87 and the British Vickers MkC, the Japanese created their first mass produced tank: the Type 89. The production of these tanks ended in 1937.

In the summer of 1935, Mitsubishi completed the prototype of one of the most famous Japanese light tanks: the Type 95 Ha-Go. It weighed 7.4 tons, had a front transmission with a rear engine, and armour between 10 and 12 mm thick. The one man turret was shifted to the left of the center axis. It held a 37 mm gun and a 6.5 mm machine gun in a bay on the rear right. Another machine gun of the same caliber was placed in the front of the tank. The tank was equipped with a 120 hp diesel engine and could reach 30 kph off-road. The engine was chosen due to its fuel efficiency when compared to a gasoline engine. The tank used a suspension developed by the Japanese engineer Tomio Hara. After experience on the harsh landscape of Manchuria, a reinforced suspension with an extra road wheel was built, which resulted in higher pressure dissipation and softened blows when moving on bumpy terrain. Japanese tankers liked the Ha-Go due to its simplicity and reliability. One the other hand, it had many drawbacks: a lack of modern communications, no coaxial machinegun, a large amount of hatches and removable armour plates that reduced the robustness of the armour. Nevertheless, out of all the Japanese tanks of the time, the Ha-Go was the only one to remain in production until 1945.

In the second half of the 1930s, the Tokyo Gasu Denki company presented the military with a prototype of the small Type 97 Te-Ke tank, developed on the base of the British MkVI tankette. The tank weighed 4.7 tons and was armed with a 37 mm gun, or a 7.7 mm machine gun. Due to its small size and decent speed (42 kph), the tank could act in a reconnaissance role. The Te-Ke was adopted by the army in 1937. Aside from reconnaissance, it was also used for transport of heavy infantry guns and as a forward observer vehicle. The tank fought in China, Burma, and the Philippines. In 1944, these vehicles were used as a part of the raid on the Kwajalein Atoll.

The Hino Jidosha Kosho company created an interesting project in 1938, a speedy light Type 98 Ke-Ni tank. Due to its powerful diesel engine, it could reach a speed of 50 kph. Changes to the vehicle's suspension reduced the vehicle's oscillations at high speed. Ke-Ni had a new turret, housing two crew members. This was supposed to increase the effectiveness of armament. The turret had a 37 mm cannon and a 7.7 mm machinegun to the right. A Type 98B variant existed, with a star-shaped engine and a Christie suspension, but it was not mass produced. The Ke-Ni was produced in small numbers in 1942-1943, 20-100 tanks, depending on the source.

In 1936, the Japanese military revised their requirements for medium tanks. Engineers were expected to create more maneuverable and more protected vehicles, armed with more powerful guns. The engineers of the Technical Department of the Imperial Army designed the 9.8 ton Chi-Ni tank to match these requirements, and Mitsubishi designed the 15 ton Chi-Ha.

The medium Chi-Ni tank was equipped with a 135 hp engine, allowing it to reach a speed of 30 kph. It had a tail on the rear to aid it in crossing trenches, pits, and escarpments. Sloped armour plates improved the vehicle's protection. The crew consisted of three men. The military first favoured this tank, but when the war with China started, it was obvious that its low mass and low cost lost out to the Chi-Ha's thick armour.

The Chi-Ha was adopted in 1937, and mass production began in 1939, when the war in China was already finished. The vehicle could reach a speed of 40 kph, was armed with a Type 9757 mm gun and two 7.7 mm machineguns. The thickness of the front armour reached 25 mm. The tank was assembled by riveting armour plates together. The conical turret was shifted to the right of the tank's axis. In 1940, after the Battle of Khalkin-Gol, the Shinhoto Chi-Ha modification was produced. It had a new turret, with a 47 mm L/48 gun. A shell from this gun penetrated 50 mm of armour at 500 meters. The Chi-Ha was widely used: in China, Singapore, Malaysia, Guadalcanal. 1200 vehicles were built between 1938 and 1942.

Japan was a late player in the tank game, compared to the Western nations, but by the start of WWII, its engineers had about 20 independent tank projects under their belts. It is not possible to cover them all in this article, but it is clear that the Land of the Rising Sun advanced quickly, creating its own school of armoured warfare.

In the second article, we will talk of wartime Japanese tank projects, and briefly discuss the structure of the Japanese armoured forces and its tactics.

Japanese tanks 1939-1945

In 1940, a thorough modernization of the Chi-Ha medium tank took place, and the engineers ended up with a brand new vehicle: the Type 1 Chi-He. One of the most important differences between the Chi-He and its predecessor lay in the hull: it was the first Japanese tank whose armour was welded, not riveted. This positively influenced the vehicle's survivability in combat. Furthermore, the thickness of armour increased, reaching 50 mm in the front and 20 on the sides. The tank got a new three man turret, adding a new crewman, a loader. This eased the job of the tank commander. The Chi-He was equipped with the Type 1 47 mm gun, developed by equipping the anti-tank gun with a better recoil mechanism and trigger. This gun's shell penetrated 68 mm of armour at 500 meters. The same gun was installed on the Shinhoto Chi-Ha. The thicker armour led to the Chi-He's mass increasing by 1.5 tons over the Chi-Ha. The new 240 hp Mitsubishi engine not only compensated for the increase, but let the Chi-He accelerate to 44 kph. The new tank was produced by the Mitsubishi company and the Sagami arsenal starting in 1941. The production of the Chi-Ha did not cease. 601 Chi-He tanks were built before 1945. Individual vehicles remained in use by the Japanese army until the 1960s.

Japanese engineers modernized several medium tanks in 1938 through 1944, but these modernizations mostly ended with only several prototypes. For example, the Type 2 Ke-To was built out of the light Ke-Ni tank, but only a couple were produced. A light Ke-Ri tank with a 57 mm gun in a new turret was built from the Ha-Go, but in a small series. There were others, but the limited scope of this article does not allow for their mention.

In 1944, work on a new light tank was completed: the Type 5 Ke-Ho. It was similar to the Chi-He in layout and armament, but only had a two-man turret and a 150 hp diesel engine. The suspension consisted of six doubled road wheels on each side. The Ke-Ho had 25 mm of armour in the front, and 12 on the sides and rear. The tank successfully passed trials, but did not have time to enter production before Japan's surrender.

In 1943, the Osaka arsenal developed a new 75 mm gun, the Type 3, equipped with a muzzle brake. The gun could penetrate 90 mm of armour at 100 meters, and 65 at 1000 meters. A new medium tank carried this gun: the Chi-Nu, accepted by the army in 1943. Its design was a repeat of the Chi-He, but it weighed 18.8 tons, and could accelerate to 39 kph. Only 60 tanks of this type were built before the war. All of them were stationed on the Home Islands, and did not see combat. Compared to other Japanese vehicles of the time, the Chi-Nu had the most powerful armament.

Another vehicle that did not make it into production in time was the Type 4 Chi-To medium tank. Compared to the Chi-Nu, it had thicker armour (75 mm in the front and 35 on the sides), and had a long 75 mm gun, developed from an AA gun, The tank also carried two Type 97 7.7 mm machineguns. Compared to earlier tanks, the Chi-To was very heavy, 35 tons. Using a 400 hp engine, it could reach a speed of 45 kph. A redesigned suspension and wide tracks gave the tank good off-road performance. Five were built before 1944.

Two medium Chi-Ri tanks were built using the Chi-To design. This vehicle had two guns. One was a 75 mm gun, the same as the one in the Chi-To turret. The second was a 37 mm gun from the Ke-To, placed in the hull. The second prototype had the 37 mm cannon replaced with a machinegun. The tank's hull was welded, the side armour plates were slightly sloped. There is a theory that the tank's designers were inspired by the German Panther. The tank was equipped with a Kawasaki diesel engine, a licensed clone of a BMW model. Compared to the Chi-To, the tank had thicker armour: the sides grew to 50 mm. The maximum speed of this vehicle was 45 kph.

Japanese tanks after WWII

After its surrender in 1945, Japan dropped out of the tank design game. However, the escalating Cold War led to the Americans arming Japan in the 1950s with limited amounts of armoured vehicles. 250 M4A3E8 tanks were shipped since 1950, and 375 M24 Chaffee tanks arrived in 1952.

In 1954, the Japanese Self-Defense Force ordered the development of a new tank. Requirements were formulated based on the potential theatre of operations: the tank must be compact and light enough to be delivered to battle in a special truck. A 90 mm gun was to be used.

Several projects were developed to match these requirements. The first was the STA-1. This vehicle was equipped with a Mitsubishi DL10T water-cooled diesel engine, later replaced with a Mitsubishi 12HM-21WT engine, which had less problems with overheating. The gun had a caliber of 90 mm, as ordered. The tank was only 2.2 meters tall. The vehicle was not mass produced. One of its drawbacks was that the loading process was inconvenient.

In parallel with the STA-1 prototype, the STA-2 was developed. It also was not mass produced, but the STA-3 and STA-4 were built out of the first and second prototype. They were very similar to their predecessors, but the STA-3 had a semi-automatic loading system, which increased the rate of fire.

Three years of work on the STA-3 and STA-4 ended with the production of the Type 61 MBT in 1961. It weighed 35 tons and had a 90 mm rifled cannon with a muzzle velocity of 910 m/s. The secondary armament consisted of two Browning machineguns: a .30 cal and a .50 cal. The front armour was 55 mm thick, the turret was 114 mm thick. The tank had a top speed of 45 kph. 560 Type 61 tanks were built between 1961 and 1975.

In 1964, the STB project began. The new vehicle had to weigh 38 tons and accelerate to at least 50 kph. The main gun would be the British Royal Ordnance L7.

In 1968, work on the STB-1 prototype started. In one year, the tank began trials, which lasted until 1970. In Ocrober of 1970, the tank was first shown in a parade of Japan's Self Defense Force. However, it did not see mass production, due to design flaws. Work on the STB project continued until 1973, when STB-6 entered service as the Type 74. However, that tank falls outside of the scope of this article.

Let us make some conclusions. Japan's tank building school was self-made, and developed quickly. From the 1930s to the end of WWII, Japan developed dozens of unique projects, most of which existed not only on paper, but in metal, even if only one or two were built. Engineers had to consider the hot climate, mountains, jungles. Japanese tanks were only inferior to those of Japan's strongest enemies: the USSR, the US, and Great Britain. Several vehicles developed towards the end of WWII could mean trouble for Shermans, Pershings, and T-34s. However, Japan lacked the industrial base to build them. When, after a forced decade-long hiatus, Japan returned to the world of tank building, the vehicles it produced were no worse than those of foreign competitors.

Original article available here: part 1 and part 2.

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