Operation Iskra (), a Soviet military operation in January 1943 during World War II, aimed to break the Wehrmacht's siege of Leningrad. Planning for the operation began shortly after the failure of the Sinyavino Offensive. The German defeat in the Battle of Stalingrad in late 1942 had weakened the German front. By January 1943, Soviet forces were planning or conducting offensive operations across the entire German-Soviet Front, especially in southern Russia; Iskra formed the northern part of the wider Soviet 1942–1943 winter counteroffensive.
The operation was conducted by the Red Army's Leningrad Front, Volkhov Front, and the Baltic Fleet from 12 to 30 January 1943 with the aim of creating a land connection to Leningrad. Soviet forces linked up on 18 January, and by 22 January, the front line had stabilised. The operation successfully opened a land corridor wide to the city. A railroad was swiftly built through the corridor and allowed more supplies to reach the city than the Road of Life, across the frozen surface of Lake Ladoga, which significantly reduced the possibilities of the capture of the city and of any German–Finnish linkup.
The success led to Operation Polyarnaya Zvezda less than two weeks later, which aimed to decisively defeat Army Group North and to lift the siege altogether. Polyarnaya Zvezda failed by achieving only minimal progress. Soviet forces made several other attempts in 1943 to renew their offensive and to lift the siege completely, but they made only modest gains in each one. The corridor remained within range of German artillery, and the Red Army did not finally lift the siege until a year later, on 27 January 1944.
Background
The siege of Leningrad started in early autumn 1941. By 8 September 1941, German and Finnish forces had surrounded the city, cutting off all supply routes to Leningrad and its suburbs. However, the original drive on the city failed and the city was subjected to a siege. During 1942 several attempts were made to breach the blockade but all failed. The last such attempt was the Sinyavino Offensive. After the defeat of the Sinyavino Offensive, the front line returned to what it was before the offensive and again separated Leonid Govorov's Leningrad Front in the city from Kirill Meretskov's Volkhov Front.
Despite the failures of earlier operations, lifting the siege of Leningrad was a very high priority, so new offensive preparations began in November 1942. In December, the operation was approved by the Stavka and received the codename "Iskra" (Spark). The operation was due to begin in January 1943.
By January 1943, conditions were improving for the Soviets. The German defeat in the Battle of Stalingrad had weakened the German front. The Soviet forces were planning or conducting offensive operations across the entire front, especially in southwestern Russia. Amidst these conditions, Operation Iskra was to become the first of several offensive operations aimed at inflicting a decisive defeat on Germany's Army Group North.
Preparations
The area south of Lake Ladoga is a heavily forested area with many wetlands (especially peat deposits) close to the lake. The forest shielded both sides from visual observation. Both factors greatly hindered the mobility of artillery and vehicles in the area, providing a considerable advantage to the defending forces. The Sinyavino heights were a key location, with terrain higher than the surrounding flat terrain. Because the front line had changed very little since the blockade was established, German forces had built an extensive network of interconnected trenches and obstacles, interlocking artillery and mortar fire. The Neva River was partially frozen, allowing infantry to cross.
German preparations
The Germans were well aware that breaking the blockade was very important for the Soviet side. However, due to the reverse at Stalingrad and the Soviet offensive at Velikiye Luki to the south of Leningrad, Army Group North was ordered to go on the defensive and was stripped of many troops. The 11th Army, which was to lead the assault on Leningrad in September 1942, and which had thwarted the last Soviet offensive, was transferred to Army Group Center in October. Nine other divisions were also reassigned to other sectors.