On July 5, 1943, the long-awaited German assault began. Despite the arrival of the powerful new German tanks, the Soviets ground their advance down to a crawl thanks to the stiff fortifications they'd had time to lay in place. The Germans planned their assault for July 5, 1943 but a defector warned the Soviets and denied them the element of surprise. Even without the warning, General Zhukov had found plenty of time to fortify Kursk with layer upon layer of pillboxes, minefields, and more. He planned to bloody the Germans with this staunch defense and weaken them for later. The new German tanks, such as the Tiger, arrived only to find themselves outnumbered by numerous Soviet T-34s and ill-supported by maintenance crews who were stretched too thin by the number and variety of new tanks being deployed. General Manstein ordered his strongest tank unit to push through, targeting the small town of Oboyan, but although he made the most progress along the line of the assault, even he had not expected resistance on this scale. By the next day, the Germans had barely reached the second line of Soviet defenses, and while they hadn't been forced to retreat anywhere, they were distinctly behind schedule. Hitler needed them to win. It wouldn't win the war, but he hoped that it would force the Soviets to withdraw, leaving him free to concentrate on the Western front and the threats from the United Kingdom and the United States.