The Soviet T-34 tank is often credited as being one of the top tanks used in WWII. It was the end result of a design process going back to the mid 1930s. The first two prototypes were created in January 1940. The T-34 was intended to replace a plethora of Soviet light and medium tanks then in service. As was common in the Soviet Union, there was intense political pressure to continue building the old tanks or to cancel the new tank entirely. The poor performance of the existing Soviet arsenal in the Winter War with Finland provided the push needed to get production going. The T-34 used the Christie coil-spring suspension with a slack track tread system. It was one of the first combat tanks to use well sloped armor and used wide tracks to give it very low ground pressure. The tanks appearance on the front delivered a large shock to the Germans. In 1941 T-34s armor could defeat all German antitank weapons except the 88mm flak gun at normal combat ranges. Its 76.2mm main gun could penetrate the frontal armor of any 1941 German tank. While the T-34 was a great step forward in tank design there were several problems with it. The 2 man turret was a major drawback forcing the commander to act as the gunner as well. The commander's battlefield visibility was also poor; the forward opening hatch forced him to observe the battlefield through a single vision slit and traversable periscope. There were also severe mechanical problems and reliability issues. During one road march in June 1941 the 8th Soviet Mechanized Corps lost half of its vehicles to breakdowns. By 1943 the 76.2mm could not penetrate the Panther's frontal armor and was out-ranged by its 75mm gun and by the Tiger's 88mm gun both of which could penetrate the T-34s armor at all combat ranges. The T-34 / 85 introduced a new 85mm main gun, a new 3 man turret and some improvements to reliability. The new turret finally allowed the commander to focus on running the tank and the 85mm gun, while still inferior to the Panther and Tiger, allowed the T-34 to remain competitive. Like the M-4 Sherman, the T-34 main advantage was the huge numbers produced. By the end of 1945 more than 57,000 T-34s had been built (34,780 T-34 / 76 and 22,559 T-34 / 85) with production continuing until 1958 in Poland (1,380) and Czechoslovakia (3,185). This makes it the second most produced tank in the world (after the T-54/55). The T-34 / 85 was armed with a 85 mm ZiS-S-53 canon and two 7.62mm DT machineguns. This model shows a T-34 / 85 with the 7th Guards Tank Corps, 55 Guards Tank Brigade in Berlin in April 1945.