Mechanised corps (Soviet Union)
A mechanised corps was a Soviet armoured formation used prior to the beginning of World War II and reintroduced during the war, in 1942. Pre-war development of Soviet mechanised forces. In Soviet Russia, the term armored forces (thus called "Bronevyye sily") preceded the mechanised corps. They consisted of the autonomous armored units ("avtobroneotryady") made of armored vehicles and armored trains. The country did not have its own tanks during the Civil War of 1918–1920. In January 1918, the Russian Red Army established the Soviet of Armored Units ("Sovet bronevykh chastey", or "Tsentrobron’"), later renamed to  Central Armored Directorate and then once again to Chief Armored Directorate ("Glavnoye bronevoye upravleniye"). In December 1920, the Red Army received its first light tanks, assembled at the Sormovo Factory. In 1928, it began the production of the MS-1 tanks ("Malyy Soprovozhdeniya 1", 'Small Convoy 1'). In 1929, it established the Central Directorate for Mechanisation and Motorisation of the Workers’ and Peasants’ Red Army. Tanks became a part of the mechanised corps at this point. During this time, and based on the experience of the Civil War with its sweeping movements of horse-mobile formations, Soviet military theorists such as  Vladimir Triandafillov born in Pontus of Greek parents and Konstantin Kalinovsky elaborated the principles of combat use of armored units, which envisioned a large-scale use of tanks in different situations in cooperation with various army units. In the mid-1930s, these ideas found their reflection in the so-called deep operation and deep combat theories. From the second half of the 1920s, tank warfare development took place at Kazan, where the German Reichswehr was allowed to participate. In 1930, the First Mechanised Brigade had its own tank regiment of 110 tanks. The formation of two mechanized corps was authorized in  1932. The first two corps formed were the 11th Mechanized Corps in the Leningrad Military District and the 45th Mechanized Corps, formed in the Ukrainian Military District. That same year, the Red Army established the Military Academy of Mechanization and Motorization of the Workers’ and Peasants’ Red Army (which existed up until 1998 as the Military Academy of Armored Units named after Rodion Malinovsky). Mikhail Katukov had his first major command as acting commanding officer of the 5th light Tank Brigade of the 45th Mechanized Corps in 1938. In 1931–1935, the Red Army adopted light, medium, and later heavy tanks  of different types. By the beginning of the 1936, it already had four mechanised corps, six separate mechanised brigades, six separate tank regiments, fifteen mechanised regiments within cavalry divisions and considerable number of tank battalions and companies. The creation of mechanised and tank units marked the dawn of a new branch of armed forces, which would be called armored forces. In 1937, the Central Directorate of Mechanization and Motorization was renamed to Directorate of Automotive Armored Units ("Avtobronetankovoye upravleniye") and then to Chief Directorate of Automotive Armored Units ("Glavnoye avtobronetankovoye upravleniye"), headed by Dmitry Pavlov. This was carried out under  Marshal Tukhachevsky, one of the generals shot in June 1937 in the Great Purge. Soviet armored units gained some combat experience during the Battle of Lake Khasan (1938), the Battle of Khalkhin Gol (1939) and the Winter War with Finland (1939–1940). But these operations and also observation of the Spanish Civil War, led People’s Commissar for Defence Marshal Voroshilov to the conclusion that the mechanised corps formations were too cumbersome. A decision was taken to disband them in November 1939, and to distribute their units among infantry. This was a mistake, as the success of German panzer divisions in  France showed, and in May 1940 Voroshilov was replaced by Marshal Timoshenko. Future Marshal Zhukov had drawn different conclusions from his own experience at Khalkhin Gol and from the other battles. The decision was reversed, and on 6 July 1940 the NKO ordered the formation of nine new mechanised corps, and in February and March 1941, began forming an additional 20. By June 1941, 29 existed in the Red Army, although the degree of staffing they had significantly varied. However, there was not enough time before the German attack in June 1941 to reform the mechanised corps units fully and  for them to reach their former efficiency. Period 1940–41. In June 1941 there were twenty-nine mechanised corps in various stages of formation. The plan was for each of them to have about 36,000 men and 1,000 tanks, and a few approached that strength level by the time war with Germany broke out . Of this number, two formations especially stood out: 4th and 6th Mechanized Corps. On 22 June 1941 each of these was fully formed, armed with more than 900 operational tanks, and stationed not further than 100–300 kilometers from the border. Considering the armor qualities, each of these  formations had a substantial concentration of the T-34 and KV-1 tanks. Both of these formations, having more than 350 of the T-34 plus KV-1, could be reasonably expected to break through any German Panzer Corps of the time, not to say Army Corps. Such estimation is based on sheer number of concentrated tanks, their main armament, the thickness of their armor, their actual failure rate, the eventual losses to aircraft, and normal scheduled maintenance. What it does not count are human-related factors. That being said, during the war against the Axis, all mechanised corps stationed in frontline areas were  destroyed during the early phase of the invasion of the Soviet Union (including 4th and 6th), and less than a month after the attack, the Red Army formally abolished the Mechanised Corps as a formation type. Remaining tanks were concentrated in smaller formations that were easier to handle. Period 1942–46. In September 1942, the General Headquarters ("Stavka") authorized the formation of a new type of mechanised corps which was to become the main operational mechanised formation for the remainder of the war. They were about the same size as a German panzer division, and designed as a true combined-arms  formation with a good balance of armor, infantry, and artillery. Mechanised corps were not to be used in breakthrough battles, but only in the exploitation phase of an operation. They shared with the new Tank Corps a four-manoeuvre-brigade structure – three mechanised brigades and one tank brigade, plus an anti-tank regiment, artillery, and other support units. The new tank corps had three tank brigades and one mechanised brigade. A total of thirteen mechanised corps were formed during the war against the Axis nations, nine of them becoming guards mechanised corps. A further corps, the 10th Mechanised Corps, was  formed in June 1945 and saw action during the Soviet invasion of Manchuria. The 1st, 3rd, and 9th Guards Mechanised Corps were equipped with Lend Lease tanks, Sherman M4A2. The mechanised corps were converted to mechanised divisions relatively quickly after the war – by 1946 in most cases. Composition of a mechanised corps (1941). Total The formation was seen as very tank-heavy, lacking sufficient infantry or artillery to support the tank formations. The 1942 order of battle was much more flexible. Composition of a mechanised corps (1944). Total: List of Soviet mechanised corps. The listing and data here are drawn  from Keith E. Bonn, Slaughterhouse: Handbook of the Eastern Front, Aberjona Press, Bedford, PA, 2005, and V.I. Feskov et al., The Soviet Army during the Period of the Cold War, Tomsk University Press, Tomsk, 2004 (mostly pages 71–75).