When the IS-3 strutted down during the Allied victory parade along with the other 52 new tanks in Berlin on September 7, 1945, it was a stunner. The leaders of the United States and the United Kingdom were left with their mouths wide open, clearly surprised at the far more advanced arsenal of Soviet tanks that they had not seen before. In fact, a very concerned General Dwight Eisenhower was photographed during the ceremony: An indicator that something was up.

Soviet IS-3 Heavy Tanks pass the saluting base on the Charlottenburg Chaussee in Berlin during the Four Nations VJ Day parade. (No 5 Army Film & Photographic Unit, Christie J (Sergeant), Public domain, via Wikimedia Commons)


General Eisenhower had really something to be worried about, as the Soviet’s IS-3 was a game-changer and impressive, even by today’s standards. It belonged to the 71st Guard Heavy Tank Regiment of the 2nd Guards Tank Army. It appeared to be a well-thought-out piece of equipment, built from the ground up to make sure that it would have ample ballistic protection from all possible directions of assault. Its “pike nose” and new hemispherical turret were both heavily armored would ensure that there would be no weak spot that the enemies could exploit.

The IS-3 carried 28 rounds that were split between 18 HE-Frag and 10 AP. It was also fitted with a D-25T 122 mm main gun that was proven powerful and effective in killing German heavy armor during World War II. The key details of the IS-3 were included in the declassified intelligence reports from 1954 to 1958. Here are those:

  • Weight: 46 tons.
  • Crew: four.
  • Engine: 520 HP V-12 diesel.
  • Speed: 25 mph.
  • Armament: 122mm D-25T (12.7mm AA MG/7.62mm coax machinegun).
  • Armor: Glacis: 4.7 inches (119mm) angled at 55 degrees = 8.2 inches (208mm); main gun mantlet: 7.9 inches
    (201mm) curved; turret sides: 7.9 inches (201mm)

Did Not Make it WWII

The promised protection and firepower capabilities of the IS-3 meant it was in high demand, and they rushed the production. This resulted in several mechanical issues that were unresolved by May 1945, 29 of these tanks were built at Kirovksy, but only 17 had passed testing. However, no matter how rushed the production was, it did not make it to the battlezone of World War II. As Tanks Encyclopedia wrote,

Since the IS-3 differed in many points from the previous designs, for the first time a major retooling was needed. This took time, and only in May 1945, the first three pre-series vehicles rolled out of the factory, to be thrown immediately into action in Germany, in the hands of an independent Guards Battalion. However, when they arrived, peace had already been signed.

The problems of the tank in the field became obvious very quickly.  The stresses of day-to-day operations resulted in weak weld points to crack and separate.  The shock of the 120mm gun firing in such a small turret caused it to crack as well. The engine and transmission proved faulty as well. Even the tracks and road wheels were subject to premature wearing and failure. The most likely cause was a design specification to make a heavy tank on a light chassis to make it less expensive and more mobile.  It just wasn’t working.  Correcting the structural problems added 2.5 tons to its weight which further strained the drivetrain.

The Russians were well-aware of the issues that their tanks had, so from 1948 to 1952, they worked on improving the tank, not for WWII but for the Cold War. In 1957, they did the major upgrade that would become the Cold War version of the tank: the IS-3M. This modernized version of IS-3 had additional jettisonable external fuel tanks, improved hull welding, and a new anti-air machine gun.

IS-3M in the Kubinka Tank Museum (Hornet DriverCC BY-SA 3.0, via Wikimedia Commons)

These upgrades, however, did not save the bad reputation of the IS-3 when it performed poorly during the Soviet invasion of Hungary. Its reputation was so greatly damaged that even when the improved IS-3M was impressive, it too was judged as a huge failure.