The Soviets, too, saw temptation and opportunity at Izyum, for, just as the Germans, they underestimated their opponent. Stalin, like Hitler, drew the lesson from the winter fighting that the enemy was on his last legs and, thus, favored aggressive offensive operations aimed at delivering the fatal blow. To senior leaders on the Stavka—both the chief of staff, Shaposhnikov, and his deputy, Vasilevsky, as well as Zhukov—the most sensible approach in 1942 was to remain on the strategic defensive, continue to build Soviet strength, absorb the anticipated German blow (which was expected to be aimed at Moscow), and only then, when the Germans were exhausted, go over to the offensive. For an army whose doctrine was based on “deep battle,” however, and ruled by a dictator they were loathe to cross who favored aggressive action, it was hardly surprising that many Soviet generals proposed plans for local offensives within the overall defensive context. To Stalin, a limited offensive out of the Izyum bulge seemed especially appealing, not only because the commanding general, Timoshenko, was an old ally from Civil War days, but also because, if circumstances fell right, even a short breakthrough might have a strategic impact. Although the stated intent of Timoshenko’s operation was simply to encircle and destroy German forces at Kharkov, by implication success here might well allow the entire southern front to be rolled up. Although both Shaposhnikov and Vasilevsky were horrified at Timoshenko’s plan, which meant stuffing even more forces into a constricted space, the old warhorse convinced Stalin to approve it. Although the operation was originally scheduled to start on 5 May, difficulties in assembling his forces caused Timoshenko to postpone it until 12 May. Amazingly, then, the focus of both armies along the entire length of the Russian front had fallen on a small protrusion to the west of the Donets River.14
Despite repeated warnings by Foreign Armies East of the likelihood of an enemy attack out of the Izyum bulge and the fear expressed by Bock to Halder on 5 May that “the Russians might beat us to it and attack on both sides of Kharkov,” the Soviet offensive caught the Germans unprepared. As Bock anticipated, Timoshenko’s operation was designed as a dual pincer movement: a lesser attack to the northeast of Kharkov from the Volchansk bridgehead across the Donets would tie down German forces, while the major operation would be launched from the Izyum bulge to the southeast of Kharkov. The aim of the southern pincer was not merely to envelop Kharkov but to send forces to the west to seize Krasnograd and possibly threaten even Poltava, where Army Group South had its headquarters. Moreover, the Soviet command had learned the hard lessons of 1941 and reorganized the Red Army along German lines. Rather than rely on masses of poorly trained men, the Soviets now employed a smaller infantry component supported by massively expanded tank, artillery, and air formations. Although these new tank corps performed poorly in the spring and summer of 1942, primarily for lack of motorized infantry and antitank units, they nonetheless presaged a new style of waging war that aimed to match the Germans in shock, mobility, and coordination of the supporting arms. Significantly, as well, in planning the attack, the Soviets carefully aimed their initial blow in the north at the weak Hungarian 108th Light Infantry Division, and in the south at the poorly equipped German 454th Security Division.15
Thus, although Timoshenko severely underestimated the size and skill of his opponents, almost entirely neglecting the presence of Kleist’s forces to the south of Barvenkovo, for example, his attack achieved considerable tactical surprise. Early in the morning of 12 May, following massive artillery and air bombardments, Soviet forces struck a powerful blow against the Germans that resulted, in some sectors, in profound shock and even panic. Although the inexperienced troops of the Soviet Twenty-eighth Army struggled to make headway against the prepared German defenses, the Thirty-eighth Army ripped through the Hungarian lines. To the south, the lightly armed German security division was no match for heavy armor and quickly gave way, enabling the Soviets over the next two days to open a breach in German lines over thirty miles in depth and breadth. General Paulus, in his first action as commander of the Sixth Army, reacted hesitantly and cautiously to the Soviet breakthroughs, intending, much as the Germans had done in front of Moscow, to conduct a defense based on using bypassed units as strong-points. Paulus also demanded from Bock reinforcements, which could come only from the units designated for Fredericus. Reproached by Halder for worrying about every little “blemish” in the line, Bock exploded in anger that it was “no blemish, rather our very existence is at stake.”16
Still, although the Soviet attack had struck hard, rapid German reaction, swift movement of troops and air units, and local counterattacks had checked the enemy advance in the north twelve miles from Kharkov, even as the situation in the south remained threatening. Both sides now had to make key decisions, and, in the event, it was the Germans who acted more decisively. Having saved his armored reserves for use at the right moment, Timoshenko now, on the fifteenth, hesitated to insert them into the battle. In part, this reflected his unease at strong local German counterattacks in the north. In part, it also resulted from inexperience: Soviet forces in the south had advanced so rapidly that getting reserves to the front proved far more difficult and time-consuming than anticipated. For the Germans, the situation appeared to offer much promise: with the northern sector stabilized, substantial numbers of Richthofen’s squadrons heading north, and extensive Soviet forces to the west of the Izyum salient, a successful attack by Kleist’s tanks from the south would nab an immense haul of infantry and armor. The Soviets had thrust their head deep into the noose, practically inviting the Germans to act.17
Although it was in retrospect a brilliant tactical maneuver, at the time Bock voiced pessimism as to whether Fredericus would succeed. An operation conceived as a dual envelopment would now have to proceed with only the southern pincer and no operational reserves, so he found it “difficult to see how the attack by… Kleist… will be sustained.” Hitler nevertheless decided in favor of the thrust out of the Izyum pocket. This offensive, supported by a massive array of air power and a furious artillery barrage, kicked off on 17 May, just as Timoshenko compounded his dilemma by belatedly committing his Twenty-first and Twenty-third Tank Corps to exploiting the breakthrough in the south. The German attack, spearheaded by General Eberhard von Mackensen’s Third Panzer Corps, struck northward through totally surprised troops of the Soviet Ninth and Seventeenth Armies, seizing Barvenkovo by the end of the first day, and by the evening of the eighteenth completely caving in the southern flank of the salient.18