The most western sector, that of Valtellina which descended as far as the Asiago and Folgaria plateaus, was the only one that had been ordered to adopt defensive tactics or, at least, to maintain its position. The First Army led by General Roberto Brusati had in fact to prevent any action by Austro-Hungarian troops to descend towards the plains of Veneto: if this was allowed to happen, the four other armies would have found themselves encircled.
Despite all this, even to keep high the morale and the enthusiasm of the soldiers deployed at this difficult frontline, the Supreme Command allowed the option of launching attacks in the case of situations that would evidently be favourable.
Single actions that were organized in the Lombardy sector were always marked by slow and dangerous movements. Some peaks on the southern side of Passo del Tonale, between Val Camonica and Val di Sole, were occupied but most trails and paths in the midst of perennial snows were mainly kept under surveillance from afar. There was slightly more action in the areas of Val Daone, Valle del Chiese and in Alto Garda. Abandoned by the Austro-Hungarians, some Italian divisions succeeded in pushing towards the inhabited villages of Bezzecca, Storo and Pieve di Ledro while the villages on the lake remained well guarded by Habsburg soldiers.
On the other hand in the Vicenza Prealps there were greater chances of attack by either side thanks to the accessibility of some valleys. For this reason the Austro-Hungarian troops, in definitely smaller numbers when compared to Italian forces, had to retreat so as to strengthen their defensive lines with those of the Folgaria Plateau that was excellently protected by the recent construction of efficient and modern forts with cannons and howitzers pointing towards Asiago.
The soldiers of the third corps of the First Army entered Vallagarina and occupied (with hostilities that continued till late autumn) Mount Baldo and the ranges of the Little Dolomites and of Pasubio up to Col Santo. The advanced line succeeded in pushing forward up to Castel Dante and San Colombano, less than two kilometres from the important city of Rovereto. Here the push stopped and the positions remained unchanged till May 1916.
In the Asiago Plateau the Italian troops had the chance to advance into enemy territory after only four days. The Austro-Hungarian fort of Luserna had already surrendered on 28th May and hoisted the white flag on its roof. The soldiers, however, were unable to occupy this fort: besides their characteristic slowness there was also the reaction by nearby forts that directed their shots towards Luserna as they waited for the white flag to be removed and for the men in the fort to take up again their duties.
On 12th June action on land by Austro-Hungarian soldiers succeeded in gaining possession of Mount Coston, a peak between Folgaria and Tonezza del Cimone, while in the following weeks the clashes continued especially by means of bombs and grenades that were fired by the respective forts (it is no wonder that this phase of the war has also been referred to as "the war of the forts".)
On 24th August 1915, after a long bombardment on the Austro-Hungarian fortifications in Verle and Pizzo Vezzena, a new offensive was launched. The military commanders were convinced that the troops would only meet a large heap of ruins. However, the forts had remained intact and the clashes that took place around the Vezzena Pass were one of the first massacres in the sector of the First Army. The arrival of abundant snowfalls towards the end of October blocked the greater part of these initiatives until the following spring.
