When Operation Barbarossa began, the Red Army was equipped with 508 new KV tanks. So effective was its armour that the Germans were incapable of destroying it with their tanks or anti-tank weapons and had to rely on 88 mm anti-aircraft guns (flak) or 105 mm guns to knock them out. Only a few of these tanks were used to good effect, but one event of the Battle of Raseiniai was a notable example. On 23–24 June, a single KV-2 effectively pinned down elements of the 6th Panzer Division–the spearhead of Panzergruppe 4–for a full day at the bridgeheads of the Dubysa river near Raseiniai, Lithuania, playing a prominent role in delaying the German advance on Leningrad and destroying around two dozen German tanks.
On 14 August 1941, the vanguard of the German 8th Panzer Division approached Krasnogvardeysk (Gatchina) near Leningrad (now known again as Saint Petersburg), and the only Soviet force available in an attempt to stop the German advance consisted of five well-hidden KV-1 tanks, dug in within a grove at the edge of a swamp. KV-1 tank No. 864 was commanded by the leader of this small force, Lieutenant Zinoviy Kolobanov.
German forces attacked Krasnogvardeysk from three directions. Near Noviy Uchkhoz settlement the geography favoured the Soviet defenders as the only road in the region passed the swamp, and the defenders commanded this choke point from their hidden position. Lieutenant Kolobanov had carefully studied the situation and readied his detachment the day before. Each KV-1 tank carried twice the normal amount of ammunition, two-thirds of which were armour-piercing rounds. Kolobanov ordered his other commanders to hold their fire and await orders. He did not want to reveal the total force, so only one tank would expose itself at a time and engage the enemy.
On 14 August, the German 8th Panzer Division's vanguard ventured directly into the well-prepared Soviet ambush. Kolobanov's tank knocked out the lead German tank with its first shot. The Germans wrongly assumed their lead tank had hit an anti-tank mine, and failed to realize they had been ambushed. The German column stopped, giving Kolobanov the opportunity to destroy the second tank. Only then did the Germans realize they were under attack, but they failed to find the source of the shots. While the German tanks were firing blindly, Kolobanov knocked out the trailing German tank, thus boxing in the entire column.
Although the Germans correctly guessed the direction of fire, they could not spot Lieutenant Kolobanov's tank, and now attempted to engage an unseen enemy. German tanks moving off the road bogged down in the surrounding soft ground, becoming easy targets. Twenty-two German tanks and 2 towed artillery pieces fell victim to Kolobanov's tank before it ran out of ammunition. Kolobanov ordered in another KV-1, and 21 more German tanks were destroyed before the half-hour battle ended. A total of 43 German tanks were destroyed by just five Soviet KV-1s (two more remained in reserve).
After the battle, the crew of No. 865 counted a total of 135 hits on their tank, none of which had penetrated the armour. Lieutenant Kolobanov was awarded the Order of Lenin, while his driver Usov was awarded the Order of the Red Banner. Later on, former Captain Zinoviy Kolobanov was again decorated by Soviet authorities, despite having been convicted and downgraded after the Winter War for "fraternizing with the enemy." After the end of World War II, Lieutenant Kolobanov served in the Soviet occupation zone in East Germany, where he was convicted again when a subordinate escaped to the British occupation zone, and was transferred to the reserves.
The battle for Krasnogvardeysk was covered up by Soviet propaganda. A monument dedicated to this battle was installed in the village of Noviy Uchkhoz in 1980, at the place where Kolobanov's KV-1 was dug in, due solely to the demands of the villagers. Unfortunately it was impossible to find a KV-1 tank, so an IS-2 heavy tank was installed there instead.
The Soviet victory was the result of a well-planned ambush in advantageous ground and of technical superiority. Most of the German tanks in this battle were Panzer IIs, armed with 20 mm guns, and a few Panzer IIIs armed with 37 mm KwK 36 L/46.5 guns. The German tank guns had neither the range nor the power of the 76 mm main gun of a KV-1, and the narrower track width of the German tanks caused them to become trapped in the swampy ground.
Some KVs remained in service right up to the end of the war, although in greatly diminishing numbers as they wore out or were knocked out. The 260th Guards Heavy Breakthrough Tank Regiment, based on the Leningrad front, operated a number of 1941-vintage KV-1s at least as late as the summer of 1944 before re-equipping with IS-2s. A regiment of KVs saw service in Manchuria in August 1945, and a few KV-85s were used in Crimea in the summer of 1944. The Finnish forces had two KV-1s, nicknamed Klimi, a Model 1940 and Model 1941, both of which received minor upgrades in their service, and both of which survived the war.