In an effort to energize the offensive, Sokolovsky committed Zhuralev’s 68th Army six hours after the beginning of the operation, but this only made the battlefield a more target-rich environment. In the north, the 31st and 39th Armies struck the XXXIX Panzerkorps near Yartsevo, but barely advanced 2km in the first two days. The 31st Army tried to commit an ad hoc mobile group comprised of Podpolkovnik Viktor F. Kotov’s 42nd Guards Tank Brigade (22 T-34, 7 KV-1, 4 T-70 amd 18 T-60s), a motorcycle regiment and an anti-tank unit, even though no breakthrough had been achieved.{168} The German 113. Infanterie-Division, rebuilt from cadres that survived Stalingrad, had deployed 27 heavy anti-tank guns in its sector and was fortunate to be provided with the new RSO tractors; the German anti-tank defences knocked out 35 of Kotov’s tanks.{169} Von Kluge reacted very quickly to the Soviet offensive, transferring a Kampfgruppe from 2.Panzer-Division and the entire 36.Infanterie-Division (mot.) to Spas-Demensk and sending the 18.Panzergrenadier-Division to reinforce the Yartsevo sector. Heinrici committed these units and Sturmgeschütz-Abteilungen 270 and 667 to local counter-attacks, which repeatedly repulsed the Soviet shock groups.
Even though Suvorov was making little progress, Sokolovsky ordered 10th Guards Army to commit Volkhov’s 5 MC. On 12 August, Volkhov’s corps conducted a 130km roadmarch to the front, under heavy attack by the Luftwaffe, but was ready to join the battle on the morning of 13 August. Leytenant Dmitry F. Loza commanded a company of Matilda tanks in the 233rd Tank Brigade of 5 MC and he recalled that the sudden appearance of Lend-Lease tanks in this sector caused a fratricide incident when his brigade launched a local attack against a German position, then returned to its start line, within sight of a Soviet artillery unit.
The three lead Matildas appeared from behind a hillock and came straight across the field. A minute later we were staggered by what we saw: the muzzle flashes of artillery fire and two burning tanks. The guns were firing direct lay. Three men from my company rushed over to the artillery unit. While they were running in that direction, the artillery unit managed to fire off a second volley. A third Matilda was stopped in its tracks, the rounds having disabled its suspension. The crews of Knyazev’s company reacted appropriately, firing high explosive rounds. Two artillery pieces were turned into twisted heaps of metal, their crews killed.{170}
Loza’s brigade lost a platoon of tanks in this incident because Soviet artillerymen were unfamiliar with the Matilda and assumed them to be German tanks. Nevertheless, the commitment of 5 MC added impetus to the 10 GA attack and Spas-Demensk was liberated on the same day. Yet it was not the commitment of more armour that gradually weakened Heinrici’s defence, but the relentlessly pounding of the Soviet artillery which ground up the German infantry. Between 7–21 August, AOK 4 suffered over 28,000 casualties, including 7,239 dead or missing. After the capture of Spas-Demensk, the Western Front continued to slowly grind its way through the German defences, but the offensive was temporarily suspended on 21 August in order to resupply and replenish depleted units. In 14 days of heavy combat between 7–21 August, the Western Front had advanced only 35–40km – roughly equivalent to what Hoth achieved during Zitadelle.
At this point, the Stavka realized that the Western Front could not hope to seize Smolensk in a single push and decided to restructure Suvorov as a multi-phase operation that would gradually slice up the German defences into digestible pieces. The next logical objective was Yelnya, in the centre of AOK 4’s line. Despite the fact that the Yelnya sector was heavily wooded and marshy, Sokolovsky asked for – and received – additional armoured support. Polkovnik Aleksei S. Burdeiny’s 2nd Guards Tank Corps (2 GTC) was transferred from Voronezh Front to reinforce Sokolovsky. After a week of refitting, the Western Front recommenced Suvorov on the morning of 28 August with a 90-minute artillery barrage, accompanied by airstrikes from 1 VA. Soviet artillery tactics were improving and the German front-line defences were badly chewed up. Attacking on a 25km-wide front, the 21 A, 33 A and 10 GA were able to penetrate 6km on the first day and extended the penetration to 12km on the second day. At that time, Burdeiny’s 2 GTC was committed and his tanks advanced 30km in a single day. On 30 August, the battered German forces were forces to abandon Yelnya. Sokolovsky continued pushing until his troops reached the Dnepr River, then halted the offensive on 7 September for another week.
Hitler had grudgingly authorized the creation of the Panther Stellung (line) on 11 August, directing it to be a line of fortifications running behind the Dnepr and extending all the way up to the Baltic, intended as a bulwark against further Red Army advances westward. However, the Panther Stellung was primarily a propaganda soundbite at this point and in the Heeresgruppe Mitte sector engineers were only just beginning to lay out defences west of Smolensk, centred on the cities of Mogilev, Orsha and Vitebsk. Von Kluge needed to buy time for the engineers to actually begin work on the Panther Stellung, so he took measures to reinforce Heinrici’s AOK 4. He ordered Model to transfer the s.Pz.Abt.505 from his AOK 9 to reinforce AOK 4 as soon as possible, although the battalion did not actually arrive until 17 September. However, before the Tigers could reach the front, Sokolovsky resumed the offensive. Having penetrated the outer defences of AOK 4, the Stavka now wanted Sokolovsky to push on to the main objectives – Smolensk and Roslavl. On 14 September, the Kalinin Front attacked first, followed by the Western Front on 15 September. This time, the Soviet shock groups made much better progress and it was clear that AOK 4 was no longer able to repulse large-scale Soviet attacks. Yartsevo was captured on 15 September, followed by Dukhovshchina on 17 September. On the same day, the Bryansk Front recaptured Bryansk from Model’s AOK 9. By 19 September, Heeresgruppe Mitte’s centre had been pierced and AOK 4 was in retreat. Von Kluge ordered Heinrici to fall back to the Panther Stellung, even though construction had just begun. On 25 September, the Western Front’s 5th Army fought its way into Smolensk and later in the day Roslavl was also liberated. It was only the fact that the Western Front’s forces were severely depleted and that there was no large mobile exploitation force available that prevented Suvorov from leading to the collapse of Heeresgruppe Mitte in 1943. Instead, von Kluge’s forces were able to withdraw to the putative Panther Stellung and established a new defensive line around Vitebsk, Orsha and Mogilev, which were heavily fortified during the winter of 1943/44.
Operation Suvorov accomplished its primary objectives of liberating Smolensk and pushing Heeresgruppe Mitte back over 150km. Sokolovsky’s Western Front used armour primarily in an infantry support role and had only two large armoured units available for exploitation. Nevertheless, the Red Army had lost 863 tanks during Operation Suvorov, about 63 per cent of the total engaged.{171} Although Soviet progress through the Heeresgruppe Mitte defensive belts was slow and costly, it did teach them a number of valuable lessons that would improve tank-infantry-artillery coordination for the 1944 campaigns. On the German side, von Kluge and Heinrici only had limited amounts of armour available and they used it in small but powerful local counter-attacks to restore the AOK 4’s deteriorating HKL. The problem was that there were fewer and fewer infantry to man the HKL, even if it could be restored.