Under the plan code named Operation Alberich, the Germans abandoned their old positions in a staged series that began in late February. The majority of their movement occurred between March 16 and 21, and the full German withdrawal to the Hindenburg Line was completed on April 5. The German withdrawal included numerous efforts to deceive the Allies, among them night movements and skeleton crews who remained behind to provide screening fire from machine guns, rifles, and mortars. The deception activities proved generally successful, and Germany completed its withdrawal to the Hindenburg Line largely unmolested.