The second Schweinfurt raid, also called Black Thursday, was a World War II air battle that took place on 14 October 1943, over Nazi Germany between forces of the United States 8th Air Force and German Luftwaffe fighter arm (Jagdwaffe). The American bombers conducted a strategic bombing raid on ball bearing factories to reduce production of these vital parts for all manner of war machines. This was the second attack on the factories at Schweinfurt. American wartime intelligence claimed the first Schweinfurt–Regensburg mission in August had reduced bearing production by 34 percent but had cost many bombers. A planned follow-up raid had to be postponed to rebuild American forces.