This was a German, Italian and Croat three-stage offensive against the partisan forces of Josip Broz Tito, and known to the Yugoslav forces as the 'Fourth Enemy Offensive', in Axis-occupied Yugoslavia (20 January/April 1943).
The Axis partners in fact launched a series of five offensives as a result of Adolf Hitler’s Führerweisung Nr 47 of 28 December 1942, which established a south-eastern theatre in the Balkans under the Oberbefehlshaber ‘Südost’, Generaloberst Alexander Löhr, who was answerable directly to Hitler. In this directive Löhr was ordered to undertake the ‘final pacification of the hinterland and destruction of the rebels and bandits of all kinds, in conjunction with the Italian 2nd Army’, and decided that the first step in this programme required the elimination of the partisan forces in Croatia and Bosnia.
‘Weiss’ (ii) was initiated to secure this objective, and for the task Löhr gathered a force of six German, three Italian and two Croat divisions as well as a number of anti-communist Četnik and Ustaše units. Under the command of Generalleutnant Rudolf Lüters, the Befehlshaber der Deutschen Truppen in Kroatien, an extemporised corps command controlled SS-Gruppenführer und Generalleutnant der Waffen-SS Artur Phleps’s 7th SS Gebirgsdivision ‘Prinz Eugen’ at Karlovac, Generalleutnant Fritz Neidholdt’s 369th Division (kroatisch) at Banija, one regiment of Generalleutnant Josef Brauner von Haydringen’s 187th Reserve-Division, Generalleutnant Karl Eglseer’s 714th Division, Generalleutnant Benignus Dippold’s 717th Division at Sanski Most, and the Croat Home Army’s 2nd and 3rd Home Defence Mountain Brigades. Generale di Corpo d’Armata Mario Robotti’s Italian 2a Armata provided Generale di Divisione Pietro Scipione’s 57a Divisione ‘Lombardia’, Generale di Divisione Furio Monticelli’s 12a Divisione ‘Sassari’ and Generale di Brigata Giovanni de Bonis’s 13a Divisione ‘Re’, and the Axis force was completed by some 20,000 Četniks. The Axis forces could thus deploy some 150,000 troops against the considerably smaller partisan strength.
The operation was schemed in three stages as ‘Weiss I’ (20 January/15 February) involving attacks on the partisan-held areas in western Bosnia and parts of central Croatia, ‘Weiss II’ (25 February/mid-March) involving operations in western and south-western Bosnia, forcing the partisans to retreat as far to the south-east as the Neretva river, and ‘Weiss III’ (launched in March by Italian forces) centred around the areas of northern Herzegovina, though the targeted partisans managed to breakout from an encirclement into northern Montenegro, and the third phase was not successfully completed.
At first, all went well for the Axis forces, the Germans pushing to the south from the Sava river into the Grimec Planina as the Italians advanced to the north from the coast to trap the partisans. Tito and his partisan forces were forced to pull back into Herzegovina and Montenegro, but then the Axis partnership began to fail, the Italians slowing and preferring to leave matters to their Croat satellite formations. As a result the Axis pincer failed to trap the partisans, who escaped into the valley of the Neretva river and played havoc with the important bauxite mines near Mostar.
By the end of March, the Axis forces had killed about 8,000 partisans and taken another 2,000 prisoner, but despite these heavy losses and the Axis forces’ tactical victory, the partisans had secured their command and their all-important hospital, and were able to continue operations. In fact, once they reached the eastern parts of Bosnia and Herzegovina, the partisans had to face only the Četnik forces, and in turn almost entirely incapacitated them in the area to the west of the Drina river. The Germans and Italians now fell out about the latter’s use of the anti-partisan Četnik movement headed by Colonel Draža Mihailovic.
Here matters stagnated, and while the Axis forces attempted to pin down the partisan forces in the Neretva river valley Tito organised major risings elsewhere in the theatre, the most significant efforts being made in Albania, Serbia, western Croatia, and the area to the north of the Sava river.