ST-A 2, the second vehicle belonged to the phase one development program of Japan’s first post-war tank.
In February, 1957 the STA 2 was completed according to the original plan. The turret and hull were built with armor plates. Compared to the STA 1, cost was increased to 112 million yen from 96 million yen.
The STA 2 was taller by 25cm and shorter by 45cm. It featured an air-cooled diesel engine, a cast turret, torsion bar suspension system, a torque converter, etc.**
Shapes of the turret, engine compartment , and the rear hull are common between the STA-1 and STA-2. But road wheels were decreased to six with the STA-2 whose hull became shorter.
Development history of Type 61
The Type 61 tank stands as Japan’s first domestically developed Main Battle Tank (MBT) post-World War II. Following Japan’s defeat in WWII, the country fell under the occupation of the Allied forces, with restrictions imposed on weapon possession and production. However, the outbreak of the Korean War in June 1950 prompted a remilitarization effort in Japan, driven by the urgency expressed by the Supreme Commander of the Allied Forces (GHQ). In 1952, during the reorganization of the National Police Reserve into the National Safety Force, Japan received weapon supplies from the U.S. military.
Notably, the M4A3E8 Sherman medium tank and M24 Chaffee light tank were predominantly provided. These American tanks surpassed their Japanese counterparts in firepower and defense, featuring an overall welded structure that showcased significant advancements in manufacturing technology. Despite their superiority, these tanks, developed during World War II, were considered outdated, as the post-war U.S. military had shifted to using the M46 Patton tank and M41 Walker Bulldog light tank as their main equipment.
The Korean War came to a ceasefire in July 1953, and a year later, in July 1954, Japan witnessed the reorganization of the National Safety Force into the Ground, Maritime, and Air Self-Defense Forces, along with the establishment of the Defense Agency to oversee and operate them. Around this time, the U.S. suggested reviving and utilizing surplus M41 light tanks and M46 tanks in various Asian countries, including Japan. This proposal gained significant support within the Ground Self-Defense Forces, anticipating the acquisition of a large number of modern tanks.
However, some members of the Ground Self-Defense Forces leadership and manufacturers like Mitsubishi Heavy Industries, involved in tank development during the pre-war era, opposed this idea. They argued for revitalizing Japan’s dormant tank development technology and domestically producing an MBT. Simultaneously, they diligently conducted foundational research on components like engines.
Their efforts bore fruit, and in 1955, the decision was officially made to develop a domestic MBT. The indigenous MBT was designated as “Chūtetsu-sha” (abbreviated as ST), replacing the “sen” (war) character with “toku” (special) to avoid implications of military strength, as stipulated by the new constitution enacted in 1947, which prohibited Japan from maintaining military forces.
By the end of January 1955, the Ground Staff Office of the Defense Agency submitted the development goals for the ST, aiming for a combat weight of 25 tons, equipped with a 90mm tank gun, a length of approximately 6.0 meters, width under 2.8 meters, and a height of about 2.0 meters. This was in response to the challenging terrain of mountainous and paddy fields in Japan, making a lighter tank more suitable for operations.
Eventually, the ST evolved into the 35-ton Type 61 tank and was officially adopted by the Ground Self-Defense Forces in December 1960. The production process faced delays, and the first production model of the Type 61 tank was delivered over a year after its formal adoption, in October 1962.
Over the course of 13 years, from 1962 to 1974, a total of 560 Type 61 tanks were produced and delivered to the Ground Self-Defense Forces. The Type 61 tank served as Japan’s MBT until the end of 2000 when it was phased out in favor of the Type 90 tank. While the Type 61 had its shortcomings, such as the lack of powerpack and automatic transmission, and being considered late for a post-war first-generation MBT, it successfully bridged the technological gap, producing a tank that held its own against similar models from other nations.
This is a suggestion for the less familiar ST-A 2 variant, the ST-A 2B, featuring unique modifications that set it apart from the ST-A 2A.
Regrettably, there is no available information or historical context explaining the features observed in the photos of the ST-A 2B. As of now, there are approximately nine images of this tank, which were uploaded to a Japanese website in 2021. The owner of these photos claims they were captured on December 13, 2000, at Kasumigaura Garrison.
The prototype ST-A2B tank, displayed at Kasumigaura Garrison as a Type 61 tank, features a Z-shaped muzzle brake that also serves as a blast deflector, rather than the original umbrella type. Due to the difference in turret shape, it appears that a makeshift shield, crafted from metal plates, was used as it cannot accommodate the standard gun shield.
In the overhead view from the top right, the ST-A2B reveals uncommon configurations on the body and turret upper surface. The single-pin tracks differ significantly in shape from the mass-produced type, resembling the pattern seen on the Imperial Japanese Army’s Type 4 tank.
Currently, I can only highlight the distinctive features of this vehicle and identify the apparent differences from the ST-A 2A.
As you likely observed upon your initial glance, the most prominent feature of this vehicle is the unusual shape of its large, flat mantlet, distinct from the curved mantlet on the ST-A 2A. The reason behind the utilization of this particular mantlet remains unknown.
Note the hole for M1919A4 coaxial machine gun is missing from this mantlet
I hypothesize that this mantlet could have been designed to accommodate the installation of the Type 61 90mm gun. It’s plausible that the original curved mantlet was incompatible with the specifications of the new gun.
Upon a more detailed examination of the interior image, a small portion of the gun breech is discernible, revealing its similarity to the gun breech of the Type 61. This lends further credence to the likelihood of a gun replacement on the ST-A 2B.
Top image is inside the ST-A 2B, Below is inside Type 61.
Despite their shared similarities, it’s crucial to highlight that the muzzle brake on the ST-A 2B differs from the type found on the Type 61.
Umbrella type has better control ability but the T-type is superior in next shell firing performance so it was adopted.
Side view shown a machine gun mount for M2 .50 cal AA gun attached to the commander hatch (ST-A 2A historically had it installed aswell).
Looking at the rear part of the chassis such as engine room it seems to be influenced by the Japanese late war tanks namely Type 4 and Type 5.
It’s worth noting the presence of a tank phone installed behind the engine muffler.
Last but certainly not least, the second significant upgrade, alongside the new gun, is the installation of an optical rangefinder. Clearly influenced by the M47 Patton, which was donated to Japan as a reference for the Type 61 development
The sign displays specifications for the Type 61, rendering the provided information irrelevant to the ST-A 2.
Fun facts: Technically, in the game, both the ST-A 1 and ST-A 2A can also be equipped with an optical rangefinder, facilitated by the rounded hood on their turrets.
Sadly it seems that this vehicle was later scrapped a few years later as it was later disappeared from the display and is instead replaced by a actual Type 61 tank (╯_╰)
General specifications (Based on already existing ST-A2 in the game):
- Hull Armor: 50/35/20
- Turret Armor: 75/75/35
- Crew: 4 (Gunner, Loader, Commander & Driver).
- Mass: 34.2 tons
- Engine: Mitsubishi DL10T 4-stroke V-type 12-cylinder liquid-cooled turbocharged diesel engine 500 horsepower at 2,200 rpm
- Max Forward speed: 45 km/h
- Max Reverse speed: 17.4 km/h
- Main Armament: 90mm L/52 Type 61
- Secondary Armament: M2 12.7mm Heavy Machine Gun
Type 61 90mm gun ammunition
From left to right: M313 WP (New color), M313 WP (Old color), M71 HE, M318A1 AP-T & M431 HEAT-T
Drawing of ST-A2: