'Sonnenstich' was a German and Croat operation against the brigades of the 29th 'Herzegovina' Division of the partisan forces of Marshal Josip Broz Tito in the Nevesinge area of the Dalmatian coast in German-occupied Yugoslavia (18/29 July 1944).
Together with 'Draufgänger', 'Fliegenfänger' and 'Röslein', 'Sonnenstich' was part of the quartet of operations planned and undertaken by General Franz Böhme’s 2nd Panzerarmee in July 1944 to prevent the concentration of partisans in eastern Herzegovina and the Lim river area in preparation for an advance into Serbia. Originally to have been launched on 13 July and end on 24 July, the operation was led by Generalleutnant Fritz Neidholdt, commander of 369th Division, who divided the operation into four phases for the clearance of the 'Red Republic', namely the area bounded by Burmazi, Bjelojevići and Gornje Hrasno. The villages of Zagnjezđe and Udora, some 5.5 miles (9 km) to the south-west of Stolac, were to be destroyed, their male populations hanged and their women and children interned as reprisal for the partisans' execution of a German fighter 'ace', Joachim Kirschner, whose aeroplane had been shot down by US Army Air Force fighters. The operation was to have ended with remains of local partisan forces being pushed into Montenegro pursued by Četnik detachments reinforced by German troops and there destroyed in 'Rübezahl'.
From the north, in the area of Nevesinje, the Kampfgruppe 'Döll' (parts of the 3/370th Grenadierregiment [kroatisch], detachments of other units including the 3/4th Regiment 'Brandenburg', and the Četnik 'Bileća', 1st 'Nevesinje' and 2nd 'Nevesinje' Brigades) advanced to the south from 18 July, while a second Kampfgruppe (the 10th Kompanie and 11th Kompanie of the 370th Grenadierregiment [kroatisch]) started its advance from the coast in the area of Cavtat, to the north-east of Dubrovnik.
Undertaken by an Axis force of some 7,000 men (3,800 Germans and 3,200 allies), the operation was compromised before its launch as the partisans took note of the Axis regrouping, and two days before the planned start on 11 July the Germans attempted to push back the 11th 'Herzegovina' Assault Brigade from Gacka, but failed and were pushed back into the 13th 'Herzegovina' Assault Brigade, which had infiltrated deep into area between Stolac and Blagaj. The 369th Aufklärungsabteilung suffered heavy losses during the night of 13/14 July and retreated to its start line in Blagaj under pursuit by the 13th 'Herzegovina' Assault Brigade. This compelled the Germans to postpone the operation by one day.
In the fighting of 11 July, the partisans claimed 32 Germans killed including an officer carrying a copy of the divisional order for entire operation. This allowed the partisans to prepare a counterattack against the second phase of the German operation, which lasted from 23 to 29 July. This achieved no major success before being terminated, and the planned third and fourth phases of the operation were therefore cancelled.
A report by the 29th 'Herzegovina' Division on 5 August claimed that the formation had killed 511 Axis troops (433 Germans and Ustase, and 78 Četniks), wounded more than 800 men and taken 35 prisoners for its own losses of 37 men killed and 104 wounded. Axis matériel destroyed or captured included 22 horses (78 seized alive), three mountain guns, four heavy mortars, three light mortars, 20 light machine guns, 17 sub-machine guns, 120 rifles, and eight radios. Despite their lack of numbers and firepower, the partisans had made clever use of manoeuvre and infiltration over difficult terrain to prevent the Axis forces from reaching any of their objectives.