Hollidt’s AOK 6 was holding an extended front along the Mius River with nine infantry divisions in three corps. Although the rebuilt AOK 6 had not been seriously attacked along the Mius since early March, Soviet artillery had still managed to inflict 1,000–2,000 casualties per month during the lull, so Hollidt’s infantry units were well below authorized strength. Furthermore, the Mius was only a minor obstacle, averaging about 50 metres in width and not very deep; AOK 6 was dug in on the western side, behind mines and barbed wire obstacles. The German HKL (main line of resistance) was based upon company and battalion-size Stützpunkte. For anti-armour support, Hollidt had Sturmgeschütz-Abteilungen 209 and 243 with about 40–50 StuG-IIIs. German defensive doctrine at this point was based upon a well-defended HKL to slow the enemy advance and rapid counter-attacks to smash any breakthroughs. However, Hollidt’s only mobile reserve was Generalleutnant Gerhard Graf von Schwerin’s 16.Panzergrenadier-Division, equipped with 58 tanks (incl. 37 Pz III and 11 Pz IV).
General-polkovnik Fyodor I. Tolbukhin’s Southern Front intended to cross the Mius River between Dmytrivka and Kuybyshevo and smash through the centre of Hollidt’s line, held by the XVII Armeekorps. Tolbukhin massed the 2nd Guards Army and the 5th Shock Army in this sector with General-leytenant Karp V. Sviridov’s 2nd Guards Mechanized Corps (2 GMC) and General-major Trofim I. Tanaschishin’s 4th Guards Mechanized Corps (4 GMC) ready to exploit the expected breakthrough. In order to deceive von Manstein, Malinovsky’s Southwest Front would make diversionary attacks against Hollidt’s left flank along the Donets with 1st and 3rd Guards Armies. On the morning of 17 July, Tolbukhin attacked after a short, sharp artillery preparation. The 44th Army made a supporting attack against the XXIX Armeekorps to the south, but the main effort committed seven rifle divisions against the boundary of the 294. and 306.Infanterie-Divisionen of the XVII Armeekorps. The Soviet 8th Air Army had complete air superiority over this sector, providing effective close air support as Soviet infantry poured across the river. Both German divisions were hard hit by the Soviet artillery, suffering 2,100 casualties on the first day, and the Soviet rifle divisions quickly managed to seize a 4km-deep bridgehead across the Mius before local German counter-attacks began to slow the advance. The 44th Army’s supporting attack managed to gain a small bridgehead as well.
Hollidt realized that he needed to counter-attack immediately, before Tolbukhin got his mechanized corps across the Mius and before the XVII Armeekorps was overwhelmed. He appealed to von Manstein and the OKH for assistance, but decided to commit von Schwerin’s 16.Panzergrenadier-Division as soon as possible. Von Manstein had already committed part of Nehring’s XXIV Panzerkorps to deal with Malinovsky’s diversionary attacks around Izyum, but sent the 23.Panzer-Division on its way to Hollidt. Hitler ordered von Manstein to transfer two divisions from the II.SS-Panzerkorps and the 3.Panzer-Division to eliminate the Soviet bridgehead across the Mius front, but they would take time to disengage from the Belgorod sector.
On the morning of 18 July, von Schwerin’s division attempted to attack the left side of the Soviet bridgehead, but soon ran straight into Sviridov’s 2 GMC, which had crossed the Mius. Intense Soviet anti-tank and artillery fire broke up the German attack and von Schwerin retreated after losing 20 tanks. Once the German counter-attack had been repulsed, the 5th Shock Army continued to advance and captured the towns of Stepanovka and Marinovka. By the end of the second day, Tolbukhin’s bridgehead across Mius had been enlarged to 30km deep and 45km wide. Upon learning of von Schwerin’s defeat, Hollidt requested that Generalleutnant Nikolaus von Vormann’s 23.Panzer-Division move up quickly and launch another counter-attack against the bridgehead on 19 July. Kampfgruppe Sander, which included I./Pz.Rgt.201, a company of Marder tank destroyers and a reconnaissance company, moved out on the evening of 18–19 July and conducted a 170km night road march, with the rest of the division following. Amazingly, von Vormann’s division was able to begin an attack toward Stepanovka at 0700 hours on 19 July, but quickly ran into strong anti-tank defences, supported by tanks from 2 GMC and 4 GMC. The 16.Panzergrenadier-Division conducted a supporting attack with its 20 operational tanks. Despite some Stuka sorties and an artillery preparation, two attacks on Stepanovka were repulsed. The I./Pz.Rgt.201 lost 11 tanks destroyed and all four company commanders were killed or wounded. Altogether, 23.Panzer-Division suffered 369 casualties, including 112 dead or missing. Von Vorman claimed that his division had knocked out 14 enemy tanks and 20 anti-tank guns, but the Soviet line was barely dented.{140} Following this failed attack, both the 16.Panzergrenadier-Division and the 23.Panzer-Division shifted to the defence from 20–29 July, assisting the XVII Armeekorps’ defence. Although Tolbukhin’s infantry and armour pounded on the thin German line around the bridgehead on 20–21 July and even gained a little more ground, they could not break out. On the afternoon of 22 July, Tolbukhin committed Tanaschishin’s 4 GMC against the 16.Panzergrenadier-Division sector southwest of Stepanovka. Tanaschishin advanced with more than 140 tanks in a large formation, while von Schwerin only had a few tanks left and the assault guns of Sturmgeschütz-Abteilung 236. Once again, it was Luftwaffe batteries of 8.8cm flak guns that saved the day, destroying much of Tanaschishin’s armour before it could overrun von Schwerin’s frontline positions – the 4 GMC attack collapsed.{141}
Following the repulse of 4 GMC’s breakout attempt, a brief lull settled over the Mius Front, as Tolbukhin regrouped for another offensive. Nehring’s XXIV Panzerkorps arrived in sector and took command over both 16.Panzergrenadier-Division and 23.Panzer-Division, as well as the attached Sturmgeschütz-Abteilungen. Nehring concentrated the remaining 33 tanks and 47 assault guns into mobile reserves to help hold the HKL, which was desperately short of infantrymen. Meanwhile, Hausser’s II.SS-Panzerkorps and the 3.Panzer-Division were en route by rail to make an all-out counter-attack. Hitler decided that he wanted the LSSAH sent to Italy, so Hausser was left only with the Das Reich and Totenkopf. These forces did not arrive in Hollidt’s AOK 6 area until 27–29 July, at which point Hollidt began preparing for his major counter-attack against the bridgehead, designated Operation Roland.
Hollidt’s plan was essentially a broad-frontal attack against the entire perimeter of the Soviet bridgehead, with the main effort against the hills around Stepanovka by Totenkopf, Das Reich and 3.Panzer-Division. Hausser had a total of 119 operational tanks (including about 15 Tigers) and about 30 assault guns in his two divisions, but even after acquiring LSSAH’s remaining armour when it departed for Italy his formations were about 30 per cent below strength.{142} Generalleutnant Franz Westhoven’s 3.Panzer-Division, which had lost half its armour during Zitadelle, was able to put 37 tanks in the field, mostly Pz IIIs. Nehring’s two divisions would attack from the southwest with a total of 55 tanks, 28 assault guns and 17 Marder tank destroyers. The German XVII and XXIX Armeekorps would each also contribute one infantry division and a few assault guns to make supporting attacks on the flanks. Altogether, AOK 6 was committing five mechanized divisions with almost 300 AFVs against the Mius bridgehead. However, these German divisions could not count upon their traditional help from the Luftwaffe, which had suffered heavy losses during Zitadelle and depleted its limited fuel reserves. Fliegerkorps VIII had lost over 300 aircraft, including more than 50 Ju-87 Stukas, so close air support assets were in particularly short supply. Indeed, Zitadelle cost the Stuka squadrons eight of their best pilots, all holders of the Ritterkreuz des Eisernen Kreuzes.{143}