Case White (German: Fall Weiss), also known as the Fourth Enemy Offensive (Serbo-Croatian: Četvrta neprijateljska ofenziva/ofanziva) was a combined Axis strategic offensive launched against the Yugoslav Partisans throughout occupied Yugoslavia during World War II. It was one of the most significant confrontations of World War II in Yugoslavia. The offensive took place in early 1943, between 20 January and mid-to-late March. The Axis operation prompted the Partisan Supreme Command to enact its plans to drive toward eastern Herzegovina, Sandžak and Montenegro. In order to do this, Tito formed the so-called Main Operational Group, which eventually succeeded in forcing its way across the Neretva in mid-March 1943, after a series of battles with various hostile formations. Other Partisan format