'Polyarnaya Zvezda' was a Soviet operation, more formally known as the 'Demyansk Offensive Operation', to follow 'Iskra' in the area to the south-east of Leningrad and enlarge the land corridor to Leningrad and eliminate the Demyansk pocket (10 February/1 April 1943).

The German and Finnish siege of Leningrad had begun in the early part of the autumn 1941, and by 8 September had surrounded the city, severing all the supply routes to Leningrad and its suburbs. During 1942 the Soviets made several attempts to breach the blockade, but all of these failed. The last such attempt of 1942 was the 'Sinyavino Offensive Operation', and the defeat of this undertaking found the front line essentially unaltered, leaving a distance of 10 miles (16 km) between General Leytenant Leonid A. Govorov’s Leningrad Front in the city and General Kirill A. Meretskov’s Volkhov Front outside it.

The lifting the siege of Leningrad featured very highly on the lost of Soviet priorities, so new offensive preparations began in November 1942, only weeks after the failure of the 'Sinyavino Offensive Operation' (ii). The new operational plan was approved by the Stavka in the following month as 'Iskra'. By January 1943 the Soviets firmly believed that the strategic situation favoured them, for the Germans had been weakened by their defeat at Stalingrad, and Soviet forces were planning or fighting offensive operations across the entire front, most especially in the southern part of the USSR. 'Iskra' was schemed within this context as the first of several offensives aimed at inflicting a decisive defeat on Generalfeldmarschall Georg von Küchler’s Heeresgruppe 'Nord'.

'Iskra' was a Soviet success, albeit of a limited nature, and opened a land corridor, between 5 and 6.25 miles (8 and 10 km) wide, into the city. A railway was rapidly built through this corridor, and allowed the delivery of large quantities of supplies into the city than had been possible by the 'Road of Life', as the truck route across the frozen Lake Ladoga was called, preventing the possibility of the capture of the city and a junction of the German and Finnish forces. At the same time, however, the Stavka appreciated the fact that that 'Iskra' was not the complete solution as the corridor it had opened was narrow and lay within range of German artillery, and the important heights and strongpoint at Sinyavino were still controlled by the Germans. This led Marshal Sovetskogo Soyuza Georgi K. Zhukov, the deputy commander-in-chief of the Soviet armed forces, to order the planning, as a matter of great urgency, of a more ambitious offensive operation to extend the corridor to the south and west.

This resulted in the rapid conception of a somewhat larger 'Polyarnaya Zvezda' operation by Marshal Sovetskogo Soyuza Semyon K. Timoshenko’s North-West Front, Meretskov’s Volkhov Front and Govorov’s Leningrad Front, of which General Leytenant Vladimir P. Sviridov’s 55^th Army was a component. 'Polyarnaya Zvezda' had two primary elements: the 'Krasnoborsko-Smerdynskaya Offensive Operation' (10/13 February) to enlarge the land corridor near Mga using the Leningrad Front and Volkhov Front was the northern component, and the 'Demyansk Offensive Operation' (15/25 February) to eliminate the German salient round Demyansk using the North-West Front was the core of the southern component which in fact lasted to 1 April.

In overall terms, the northern component failed without gaining much ground, and while the southern component retook the Demyansk salient, it failed to achieve the intended encirclement of the German forces. Then, with the focus of each side drawn much farther to the south for the fighting near Kharkov and then Kursk, which demanded the commitment of both sides' reserves and reinforcements, the front near Leningrad effectively stabilised until July 1943.

The North-West Front was ordered to advance to the north-west in the direction Luga and the coast of the Gulf of Finland, thereby cutting off the whole of Generaloberst Georg Lindemann’s 18^th Army, the northernmost formation of Generaloberst Georg von Küchler’s Heeresgruppe 'Nord', in a great encirclement. Within this undertaking General Major Vladimir P. Sviridov’s 55^th Army was to break open the vital Leningrad-Moscow Highway, moving off from Kolpino in the direction of Tosno, to join with the northerly pincer attack of General Leytenant Sergei V. Roginsky’s 54^th Army of the Volkhov Front and thereby to complete the encirclement of all the German formations in the Mga sector. The highway was the single most important link between Moscow and Leningrad, and comprised a parallel road and railway. The pivot for this highway was Krasny Bor between the road and the railway line. The 55^th Army’s attack would also fall on sectors defended by other German formations to establish secure flanks and draw them into the battle.

Once this attack had succeeded, the plan was for follow-on forces to advance through the gap toward Tosno in the centre of the 18^th Army's defensive sector to the south of Lake Ladoga.

The attack was planned for 10 February 1943, and the 55^th Army (43^rd Division, 45^th Guards Division, 63^rd Guards Division and 34^th Ski Brigade) intended to launch a force of some 38,000 men and 30 tanks in the first wave, supported by 1,000 pieces of artillery and mortars, to be followed by a mobile group consisting of the 122^nd Tank Brigade and 35^th Ski Brigade.

At the end of January 1943, Teniente General Emilio Esteban-Infantes Martin, commanding the 250^th Division, a Spanish volunteer formation otherwise known as the División Azul (blue division), was aware of the build-up of the 55^th Army facing his division, a fact indicating the imminent launch of an offensive. To deflect it Martin ordered his reserve (two infantry companies and two batteries of artillery) into Krasny Bor on 2 February. On 9 February Martin ordered that at least one-third of his 4,500 men with all available automatic weapons were to pull back some 2,185 yards (2000 m) behind the Spaniards' main line, that his 269^th Regiment should be ready to give up one battalion when required, and that the 263^rd Regiment should give up one infantry company, two fusilier companies and a machine gun company to create a new reserve. Additional minefields were laid, and firing positions were revised.

The German command, in the form of General Philipp Kleffel’s L Corps of the 18^th Army, also promised to send an infantry regiment as well as two anti-tank companies with 75-mm (2.95-in) PaK 40 anti-tank guns and also a number of 88-mm (3.465-in) dual-role anti-aircraft/anti-tank guns, although only one of the latter arrived in time for the battle. The L Corps' other main formation was Generalmajor Alfred Wünnenberg’s 4^th SS Polizei-Division, and the corps was later able to field six Kampgruppen extemporised from five infantry divisions and one SS motorised brigade.

At 06.45 on 10 February 1943, a barrage by 1,000 Soviet guns and mortars opened on the Spanish lines, which were hit by a deluge of artillery shells, mortar bombs and 'Katyusha' artillery rockets. At 08.45 the barrage shifted from the front lines onto Krasny Bor itself, also striking the villages of Podolvo and Raikelevo located to the east and south-east of Krasny Bor respectively. At about 08.40 the 45^th Guards Division, 63^rd Guards Division and the 72^nd Division, followed by some tanks, advanced toward Staraya Mga, to the east of Krasny Bor, Raikelevo and Podolvo, where they were met by the 4,500 men of the 250^th Division holding the eastern flank of the line. Pinned by Soviet shelling, the Spanish units were unable to retreat toward the town and in many cases fought to the death as the Soviet forces overran the front-line positions.

Inside Krasny Bor, a company of 250^th Division held the October Railway Station, repulsing infantry charges and three tank charges by advancing Soviet forces. By 11.00 the company had been trimmed to just 40 effectives, yet managed to hold the factory until 12.00, when the survivors fell back into the town. From 09.00 to 10.40, isolated Spanish units fought off Soviet attacks but were cut off when the Soviets seized the October Railway. Now encircled, the units still holding the Leningrad-Moscow Highway decided to hold as long as possible, and were annihilated.

Meanwhile the 55^th Army had managed to advance despite the heavy casualties inflicted on it by the outnumbered but well emplaced Spanish troops. The Soviets took Raikelevo, which cut off Podolvo from Krasny Bor, where the Spanish artillery, engineer and other assorted stragglers came under attack by Soviet infantry and armour, and by 12.00 the 63^rd Guards Division reported the capture of Krasny Bor, despite the fact that the southern half of the town was still controlled by the Spanish. Soviet tanks opened fire on a hospital and retreating ambulances but were eventually beaten off by Spanish troops armed with 'Molotov cocktails' and hand grenades. During the afternoon the defenders received somewhat belated support from an attack by German fighter-bombers on the Soviet positions around Kolpino, east of Krasny Bor, while the 45^th Guards Division seized Mishkino.

Sviridov decided to insert the mobile group into the battle late on the same day, but this force was halted by a combination of fierce resistance and a sudden thaw that stopped the ski infantry from operating away from the road. The German command meanwhile reinforced the Spanish defenders with extemporised Kampfgruppen.

The 55^th Army advanced as far as the central west part of the town, and after 15.15 managed to push a small unit into the rear of the Spanish division’s forward command post. Meanwhile the remaining Spanish troops were ordered to new positions on the Izhora river to the west of the town. Here they held out against the 55^th Army’s last attacks of the day.

After 16.30 a Kampfgruppe of Generalleutnant Hellmuth Reymann’s 212^th Division and two companies each of Flemish and Lithuanian SS volunteers were able to support the Spanish with a counterattack on the forest at Staraya Rechka, and by taking over the front between the highway and the Izhora river.

At the end of the day, the 55^th Army had advanced some 2.5 to 3.1 miles (4 to 5 km) and captured Krasny Bor, Mishkino, Staraya Mirza, Stepanovka and Popovka Station. On the 55^th Army’s left wing, the attack of the 43^rd Division and 34^th Ski Brigade had gained some measure of initial success, driving Wünnenberg’s SS Polizei-Division back onto the Tosno river. On the Ishora river sector, elements of the 72^nd Division drove the Spanish back toward the river, destroying one battalion but suffering up to 70% casualties in the process.

Forward elements of the 55^th Army were surrounded in several places on 11 February, but the army remained in control of Krasny Bor by the evening. A planned counterattack by the Spanish division and Generalmajor Albert Newiger’s 112^th Division was not finally carried out as a result of concerns about the 18^th Army's overall situation.

By 13 February the 55^th Army had lost almost one-third of its initial strength and most of its tanks, and could no longer advance. The total penetration achieved reached to a depth of 2.5 to 3.1 miles (4 to 5 km) on an 8.75-mile (14-km) front. The 55^th Army’s attack had not achieved its primary objectives, but did succeed in facilitating the flanking attack by the 67^th Army in the Sinyavino sector, which had been weakened by the withdrawal of German units from this sector. The main road to Moscow was still controlled by the 18^th Army, despite the Soviet capture of 1.85 miles (3 km) of railway line.

The Soviets launched their last major attack in this sector on 19 March 1943, and this was also beaten back with heavy losses on both sides. The failure of the 55^th Army to follow through on its initial success meant that the planned encirclement of the German forces in the Mga sector had lost its northern pincer. Failures by the other attacking armies, for similar reasons, led to the overall failure of 'Polyarnaya Zvezda'. It would be almost another year before the 18^th Army withdrew from the direct approaches to Leningrad.

On 15 February the 250^th Division reported casualties of 3,645 men wounded or killed and another 300 men missing or taken prisoner, representing a 75% casualty rate. It claimed 11,000 troops of the 55^th Army had been killed in the five days beginning on 9 February, although it must be noted that these claims were probably not verified. As a result of these heavy losses and Allied pressure on the Spanish government, the division was withdrawn to Germany and later disbanded.

A new and smaller volunteer formation, the Legión Azul (blue legion) attached to Generalleutnant Hellmuth Priess’s 121^st Division, remained in combat on the Eastern Front until March 1944, when it also was disbanded and the majority of the volunteers sent back to Spain.

The 'Kransnoborsko-Smerdynskaya Offensive Operation' achieved only the most limited of useful results, and the 'Demyansk Offensive Operation' failed even before it had started, for the German evacuation of the Demyansk salient shortened the front line enough to bring the offensive to a halt. Although Zhukov made several attempts to reinvigorate the offensive throughout March, it was clear the his fronts were too exhausted to undertake further offensive efforts, and then the arrival of the spring thaw marked the end of major combat operations on the Eastern Front until the start of July.

In the north, despite the fact that it had managed to hold its line, Heeresgruppe 'Nord' was in a poor situation. It formations were stretched very thinly and therefore could mount no offensive or even restore the blockade of Leningrad. The army group’s strength in fact continue to drop throughout 1943 even as that of the opposing Soviet forces grew, and this growing disparity in strength let directly to the collapse of the German front outside Leningrad when the Soviet forces began their 'Leningrad-Novgorod Strategic Offensive Operation' on 14 January 1944.