In September 1942, Blumentritt was made Chief of Staff to Rundstedt, overall commander of German forces in the west (OB West). In this capacity, he was responsible for much of the planning to defend France against Allied invasion, and in 1943 he sent a memo to the OKH expressing his concern about the depletion of German forces along the Atlantic Wall as the Eastern Front continued to bleed resources from the West. During the invasion of Normandy in 1944, he and his commander were taken by surprise at the location of the landings on the Cherbourg peninsula, later saying, "The disposition would more truly be described as ′coast protection′ rather than ′defense′! As we did not anticipate that any landing would be made on the west side of the Cherbourg peninsula, that sector was held very lightly—we even put Russian units there."