On June 28, 1916, the Vallarsa Alpine troops stormed the fort of Mattassone, and detachments of infantry carried the ridge of Monte Trappola. On the Pasubio sector Italian troops took some trenches near Malga Comagnon. Along the Posina line their advance was delayed by the fire of heavy batteries from the Borcola.
In the Astico Valley they occupied Pedescala. On the Sette Comuni Plateau the Austrians strengthened the northern side of the Assa Valley Heights on the left bank of the Galmarara to the Agnella Pass. The Italians established themselves on the southern side of the Assa Valley and gained possession of trenches near Zebio and Zingarella.
The following day, June 29, 1916, the Italian line in the region between the Val Lagarina and the Val Sugana was pushed forward still further until it reached the main Austrian line of resistance. The Italians occupied the Valmorbia line, in the Vallarsa, the southern slopes of Monte Spil, and began an offensive to the northwest of Pasubio, in the Cosmagnon region.
Farther east on the line of the Posina Valley, the Italians took Monte Maggio, the town of Griso, northwest of Monte Maggio; positions in the Zara Valley and Monte Scatolari and Sogliblanchi. Monte Civaron and the Zellonkofel, in the Sugana Valley, fell into the hands of the Italians.
The Italians continued their advance along the Posina front on June 30, 1916, despite the violent fire of numerous Austro-Hungarian batteries dominating Borcola Pass, and also Monte Maggio and Monte Toraro. Italian infantry occupied Zarolli in the Vallarsa, north of Mattassone. On the left wing, overcoming stubborn resistance, Italian troops scaled the crest of Monte Cosmagnon, whose northerly ridges they shelled to drive out the enemy hidden among the rocks. On the Sette Comuni Plateau they kept in close contact with Austrian positions. Conflicts in the densely wooded and rocky ground were carried on chiefly by hand grenades.
Between the Adige and the Brenta the Italians continued their offensive vigorously on July 1, 1916. In the Vallarsa infantry began an attack on the lines strongly held by the Austrians between Zugna Torta and Foppiano.
Italian artillery shelled Fort Pozzacchio. On Monte Pasubio the Austrians were offering stubborn resistance from their fortified positions between Monte Spil and Monte Cosmagnon.
Along the Posina-Astico line Italian forces completed the conquest of Monte Maggio and occupied the southern side of Monte Seluggio. On the Asiago Plateau there were skirmishes on the northern side of the Assa Valley.
On July 2, 1916, in the region of the Adige Valley, the Austrians directed a heavy bombardment against the Italian positions from Serravalle, north of Coni Zugna to Monte Pasubio. Some shells fell on Ala. Italian artillery replied effectively. The infantry fighting on the northern slopes of Pasubio was continued with great violence. In the Posina Valley Italian troops occupied the spur to the northwest of Monte Pruche, Molino, in the Zara Valley (northwest of Laghi), and Scatolari, in the Rio Freddo Valley. The operations against Corno del Coston, Monte Seluggio, and Monte Cimono (northwest and north of Arsiero), the main points of Austrian resistance, were continued.
On the Asiago Plateau Italian detachments were pushed forward beyond the northern edge of Assa Valley. On the remainder of this sector there was a lull in the fighting, preparatory to further attacks on the difficult ground. In the Brenta Valley small encounters took place on the slopes of Monte Civaron north of Caldiera.