Battle of Kharkov
In May 1942, Timoshenko, with 640,000 men, launched a counter-offensive (the Second Battle of Kharkov) which was the first Soviet attempt to gain initiative in the springtime war. After initial Soviet successes, the Germans struck back at Timoshenko's exposed southern flank, halting the offensive, encircling Timoshenko's armies, and turning the battle into a major Soviet defeat.