Operation Clausewitz (German: Fall Clausewitz) was the code word initiating the defence of Berlin by Nazi Germany during the final stage of the European Theatre of World War II. Clausewitz was established in the 9 March 1945 document, Basic Order for the Preparations for the Defense of the Reich Capital (German: Grundsätzlicher Befehl für die Vorbereitungen zur Verteidigung der Reichshauptstadt), a 33-page document containing 24 separate points. The second point of the document, in full (translated) is: "The Reich capital will be defended to the last man and to the last bullet." It has been referred to as the Nazis' last stand against the Soviets.
The document divided the city of Berlin into nine operational defense zones (A to H, as slices of the outer city of Berlin and Z, its center, corresponding to the government district). It further divided the region into four concentric rings: an outer exclusion zone, extending well past Berlin's city limits; an outer defense zone extending roughly to the city limits; an inner defense zone extending out to the Berlin Ringbahn; and the Citadel (German: Zitadelle), again, zone Z. In addition to the establishment of defense zones, this document also described the overall mechanism by which Berlin would be converted to a front line city. This included:
