[1][2][3] Given that this was a region of valuable coal mines which were vital for the Hungarian railways, this was the area where the first Central Powers counterattack against the Romanian invasion of Transylvania was launched.

Despite German support, the Austro-Hungarian commander of the 144th Infantry Brigade, Colonel Ludwig Berger, "inexplicably" ordered a retreat.

[4][5] German General Hermann von Staabs, the commander of the XXXIX Corps which had assumed responsibility on 8 September for operations in the southern region of Transylvania, reacted quickly to the Austrian withdrawal.

On the 9th, Major Radu R. Rosetti from the Romanian headquarters stated to General Andrei Zayonchkovski - the Russian commander in Dobruja - that the 2nd and 12th Divisions "were coming from Transylvania".

[7] The German-led Central Powers force disposed of an exceedingly strong concentration of howitzers and mountain guns, amounting to an overwhelming superiority in artillery.

[12] The Central Powers force left behind to mask the Vulcan and Szurdok passes thus remained mostly Austro-Hungarian, consisting of the 144th Brigade reinforced by two German battalions and two batteries.

[13] However, sympathetic ethnic-Romanians living in the region immediately made General Culcer's headquarters aware that the bulk of the Germans had pulled out of the area.

Von Busse arrived in the Petrozsény Basin on 28 September and managed to assemble the five battalions of the Austro-Hungarian 2nd Mountain Brigade much faster than anyone thought possible.

On 19 September, Brigadier-General Ioan Muică's 11th Division abandoned the Szurdok Pass, retreating to Bumbești, back across the border.

[18] On 1 October, the Romanian forces held a line extending from west of Mount Tulișa to Mount Oboroca - running north of Hobicaurikány (Uricani) and Kimpulunyág (Câmpu lui Neag), Lupény (Lupeni) and Zsilyvajdejvulkán (Vulcan) - then continuing northeast through Petrozsény and Petrilla (Petrila).

The Romanian communique appears to be the correct one, given that post-war Austrian sources state that the fighting for Oboroca took place on 3 October.