Operation Fall Weiss or Fourth Anti Partisan Offensive started in January 1943, ended on April 1943. Result Total Partisan Victory.The germans wanted to surround the Partisans in Bosnia, around the river Neretva, and completely destroy the Partisans. But the Partisans do just the opposite, in a meantime they takened on surprise the germans and their collaborationist forces and completely sorrounded them and force them under siege of four or three partisan divisions. The Battle resulted in Partisan total victory in April 1943. That`s the fourth hard blow on the Axis Forces on Southern European Front. Map by SAS_19 Team from Croatia.