Since Busch’s mission was strictly defensive, most of the armour assigned to Heeresgruppe Mitte consisted of assault guns and self-propelled Panzerjägers. Aside from Mortimer’s 20.Panzer-Division, the only other division with tanks was Feldherrnhalle
, which had 20 Pz IVs and a battery of StuG-IIIs. Altogether, the PzAOK 3 had about 60 assault guns and one battalion of Nashorns (s.Pz. Jgr.Abt.59), the AOK 4 had 246 assault guns and two battalions of Nashorns (s.Pz.Jgr.Abt.655) and AOK 9 had 76 assault guns. This gave Heeresgruppe Mitte a grand total of 111 tanks, 382 assault guns and 100–120 tank destroyers (Nashorn and Marder).43 It is significant that Heeresgruppe Mitte had no Panthers at this point – one year after they had been introduced on the Eastern Front – and still relied upon the Pz IV as its main battle tank. Although German industry had increased the production of the Pz IV tank to 300 per month, the latest Ausf J version was a step backward, since it omitted the turret motor to save space and weight; this meant that German tankers using this model now had to laboriously crank the turret around by hand – a huge disadvantage in battle. Busch could have massed his assault guns in mobile anti-tank reserves with 50 or more StuG-IIIs kept behind each army, but he allowed these assets to be split up into penny packets, generally a battery or a platoon assigned to each infantry division.German intelligence expected that any new Soviet offensives against Heeresgruppe Mitte would likely focus on Vitebsk and Orsha, as they had in the past. However, since the OKH expected the main Soviet offensive would be against Model’s Heeresgruppe Nordukraine that is where the bulk of the German armour was deployed. Thus Busch’s army group was now like the French in 1940, expecting a predictable battle of position but getting a battle of manoeuvre for which it was unprepared.
On the other side, the Soviets had four fronts deployed against Heeresgruppe Mitte: Rokossovsky’s 1st Byelorussian Front, General-polkovnik Georgy F. Zakharov’s 2nd Byelorussian Front, General-polkovnik Ivan Chernyakhovsky’s 3rd Byelorussian Front and General Ivan Bagramyan’s 1st Baltic Front. After the liberation of the Ukraine, Stalin was eager to see Byelorussia liberated as well and he directed the Stavka to begin planning for a major summer offensive against Heeresgruppe Mitte. Zhukov was recalled to Moscow in late April and together with Vasilevsky and other members of the Stavka, they developed an outline for a grand offensive to be known as Bagration
. Unlike previous Soviet offensives, Bagration was intended to be a massive set-piece battle with the resources needed to achieve a decisive victory. This time, Stalin did not rush the professionals but allowed Zhukov and Vasilevsky the time they need to amass overwhelming combat power against Heeresgruppe Mitte. While most of the 118 rifle divisions allocated for the operation were at only 60 per cent of authorized strength, the Soviets would still enjoy a 3–1 superiority in infantry. This time, the Red Army would use all the tools of combined arms warfare in synchronization, in order to unlock the German defences. A massive amount of artillery support, including 13 artillery divisions, was provided for Bagration. Four air armies were deployed with over 5,000 aircraft, including 2,300 fighters – which would allow the VVS to completely dominate the airspace over the battlefield.