On the Isonzo front, both sides suffered from the winter conditions, including ice storms and avalanches. Shelling and snipers forced both sides to work at night. The mountain troops on both sides grew more proficient at raiding and specialist weapons like flamethrowers made their first appearance. Boroevic´’s outnumbered Fifth Army still lacked enough shells but constantly improving defences and superb intelligence gave him a priceless advantage.
For the Fifth Battle of the Isonzo the Italian artillery continued to rely on area fire and not a detailed fire-plan, even after new regulations were disseminated: a 48-hour bombardment by over a thousand guns was simply more indiscriminate shellfire. Late snowfall and mist only compounded the coordination problems and the Italians were driven back with heavy losses. Alpini units, supported by their own mountain artillery, had more success. Both sides began to use mining in the high alpine passes to edge towards and under enemy positions, blasting holes in San Martino in 1916 and eventually honeycombing the Little Lagazuoi in the Dolomite Range.
Conrad von Hötzendorf was eager to punish the Italians for breaking the Triple Alliance. He could not match the strong Italian forces on the Isonzo, so he decided to shift the battle westwards to the South Tyrol and ordered Colonel-General Archduke Eugen to prepare a suitable plan for April 1916. The Fifth Army yielded some of its reserves and fresh artillery soon followed. The Italian First Army was poorly deployed and Cadorna, easily distracted by a minor thrust on the Carso, became aware of Austrian preparations too late to affect the outcome. Eugen’s infantry and artillery, supplemented by the units stripped from the Russian front, were well co-ordinated and made significant gains before they outpaced their already meagre supply system and Cadorna finally managed to stabilise the front line. The Archduke was pleased with his men and, although most of his reserves were withdrawn after Brusilov’s attack, he gave a press interview to publicise the fact that the defenders had lost more men than the attackers. Eugen believed that better defences and closer infantry–artillery co-ordination gave the Austrians a huge advantage over the Italians:
[On the Isonzo] it was demonstrated what our [Trentino] offensive has now confirmed: that our men, but not the Italians, could stand the horrors of drumfire … Specifically, the close cooperation between our infantry and our artillery, and the batteries among one another has been the main source of our success. Our artillery-based defence has cost the enemy veritable hecatombs of dead … The Italian prisoners unanimously declared the effect of our artillery fire was frightful, simply unendurable. Under cover of this artillery fire, it was possible for our infantry, with […] slight losses, to tear from the enemy, position after position … The Italian artillery answered our fire only weakly – not, as captured magazines afterward showed, from lack of ammunition, but because they were holding back for our infantry attacks …
The Sixth Battle of the Isonzo, in August, finally saw the Italians use a genuine artillery fire-plan. Colonel Pietro Badoglio, later a key figure in Mussolini’s regime, was assigned to plan the offensive and he and his staff selected a range of key targets including command bunkers, known supply dumps and artillery batteries. To show his confidence in the plan, Badoglio opted to personally lead a brigade attacking Mount Sabotino. For once the Austrians misread the situation and the size of the offensive surprised them. With only four heavy batteries and fewer than 600 light and medium guns, the Fifth Army was heavy outgunned and ran ruinously low on ammunition. The artillery bombardment cut all communications to the positions on Mount Sabotino and the Italians were able to overwhelm the defenders and trap many of them in their formidable kavernen. This time, when the inevitable counter-attack came, the Italians had enough time to establish their own defensive system. A similar success was experienced on San Michele but here the Austrians ran out of ammunition and their counter-attacks were driven back with heavy casualties. Just as a breakthrough glimmered, Cadorna lost his nerve and the Italian artillery reverted to re-arranging the geography while the Austrians strengthened the new defensive line on the Plava and received urgently needed shells. Further Italian attacks were predictably beaten back after savage fighting. Russian prisoners of war were brought into the Fifth Army sector to help construct an expanded defensive system, and as the Italians dithered, fresh artillery arrived to further strengthen the position.
Once again Cadorna returned to planning how to batter his way through to the Carso and the Duke of Aosta’s Third Army was instructed to prepare the latest assault. The fire-plan on this occasion required the artillery to soften up the front line, and to use heavy guns against the rear areas before intensifying the so-called ‘annihilation barrage’ just before dawn. The 9-hour bombardment was impressive but the Austrians held firm and their surviving gunners broke up the attacks. The bombardment of a key water pumping station that supplied the front line threatened to force the defenders to retreat but some Austrian naval flying boats destroyed the Italian long-range battery by bombing.
The new Italian tactics worked when the Austrian artillery was weak or low on ammunition. The Italians, not understanding how important artillery was to the Austrian system, did not emphasise counter-battery fire. That, combined with the strong Austrian defences, meant that too many attacks were broken up before they could make any progress. Worse, poor concealment meant that the Austrians could shatter attacks even before they commenced. Technical problems also hampered the Italians: their air force was still relatively weak, flash-spotting was difficult when the guns were in kaverne and sound-ranging was almost impossible in the mountains.
The bombardment before the Eighth Battle (although involving an even more intense barrage that destroyed 41 of the Fifth Army’s guns) made real progress because of the combination of dust and fog in the Carso sector during September. Austrian counter-battery and counter-assault fire inflicted heavy casualties but the Italians retained the advantage in both guns and ammunition. By the Ninth Battle the Italians were finally using curtain barrages to protect their hard-won advances, deluging the inevitable counter-attacks with gas and shrapnel before moving on to attack the Austrian second line. Only frenzied counter-attacks straight into the Italian advance prevented a major breakthrough. The Italians had learnt a great deal in 1916 but the Austrians were better at balancing resources and results. By comparison, the Italian success ‘bore no relation to the mighty expenditure of men and materiel that it cost’.
‘It will crush us all’: The Isonzo in 1917
On the Isonzo the morale of both armies was increasingly fragile. Cadorna ignored the growing criticism from his men and listened to the siren voices of Italian politicians (who wanted the Irredenta captured) and the demands of the Allies (who wanted constant pressure on all fronts). After considering the options, the Italian Third Army was ordered to attempt yet another attack into the Carso, but this time with more supporting artillery, including 166 new heavy batteries, but there was little sign of sophistication in the fire-planning. Even though the Italians had doubled their number of guns, they still had little more than a quarter of the numbers seen on the Western Front and the uncertain ammunition supplies meant that the rate of fire for heavy guns was a fifth of that seen in the Heavy Artillery Groups of the Royal Artillery. Field Marshal Robertson, visiting the front before the offensives of 1917, was stunned by the lack of pre-battle planning: ‘no system of co-operation existed between the artillery and the infantry in the attack; in fact the relations between the two seemed strained.’
Cadorna’s tenth offensive on the Isonzo began a few weeks after Nivelle’s offensive had collapsed and was delayed by the transfer of guns from the Trentino. On 10 May some 2,150 guns and 980 mortars blasted Austrian positions northwest of Gorizia for 44 hours. Initially the intention was to form a bridgehead at Hill 383 and then seize the Bainsizza Plateau. The Austrian artillery, firing at pre-planned sectors of the defensive system, shattered the first massed assaults. However, Italian numbers, a successful bombardment and dwindling Austrian ammunition stocks meant the Italians still managed to seize part of the Tri Santi position. Even then the Austrians reacted quickly, retaking several key positions in night attacks.
In other sectors the usual problems of coordination led to ruinously heavy casualties but the Italians grimly refocused their efforts. They shifted artillery from sector to sector and their methodical battering of Austrian positions enabled gradual progress. In some sectors intense shelling prevented either side from holding the objective. The attack on the Asiago Plateau was even less successful, with heavy rain disrupting the preparatory bombardment and Austrian machine guns slaughtering the fanti struggling through the mud and barbed wire. An Alpini captain described the aftermath: ‘the mountain is infinitely taciturn, like a dead world, with its snowfields soiled, the shell-craters, the burnt pines. But the breath of battle wafts over all – a stench of excrement and dead bodies.’ With typical petulance, Cadorna was furious with the slow progress of some units and blamed everyone but himself for the inadequacies of his own plan.
To launch the second phase of the battle, on to the Bainsizza Plateau, the Italians fired a million shells in 10 hours – approximately 20 shells for every foot of the front line. Dust and smoke from the intense bombardment covered the advancing infantry and major gains were made wherever the artillery were able to dominate the battlefield. The Austrians retained the key observation posts and utilised units released from the Eastern Front, using more flexible tactics and working more closely with their artillery support, to counter-attack and many of the Italian gains were lost. During the savage fighting both sides expended prodigious amounts of ammunition – the Austrian Fifth Army fired almost 2 million shells during the battle – a rate of expenditure that Austria’s industrial base could not support.
After a short pause, during which Cadorna displayed a ruthless disregard for the simmering discontent within the army, the Italians began planning the Eleventh Battle, which Cadorna described as a ‘general simultaneous attack’. The Second and Third Armies would take both Gorizia and the entire Bainsizza Plateau before capturing Tolmein, the Austrian Isonzo army’s main railhead. However, even if Cadorna’s plan succeeded, the Bainsizza was a rugged wilderness that would prove a poor basis for a fresh offensive, and Boroevic´ recognised this flaw in the plan for the eleventh Italian offensive far better than did his Italian opposite number. The Italians massed 3, 750 guns and 1,900 mortars, almost three times the Austrians’ total (450 heavy guns and 1,250 field and mountain guns), and four times the ammunition; the artillery duel would be the largest on that front. The barrage commenced on 18 August with the Italian guns, howitzers and mortars mercilessly hammering the entire front line. The quality of the artillery preparation was higher than in earlier battles and there were a small number of Allied batteries supporting the attack. In some sectors the defenders were rapidly cut off from headquarters and the defending corps commanders found it difficult to coordinate counter-attacks or to update the Isonzo army’s headquarters on the progress of the battle. Elsewhere the difficult terrain and poor Italian planning gave the Austrians enough time to reorganise and prevent a breakthrough.
Weak planning left the Italians unable to capitalise on their gains. Despite their collapsing defences, the Austrians could choose to withdraw or to feed troops into the meat-grinder. Boroevic´ was assured by the High Command that a counter-offensive was being planned and commenced a series of skilful Austrian withdrawals that delighted the Italians but ensured that he was able to consolidate on new positions on the eastern edge of the plateau. The end result was that the Italians secured most of the Bainsizza Plateau but stalled in front of Boroevic´’s new position, unsure of how to proceed. Monte Santo was taken by coup de main but desperate assaults on San Gabriele by massed columns were torn apart by artillery and machine-gun fire. Desperate counter-attacks, supported by heavy artillery, prevented the last of the Tri Santi from falling; the mountain is said to have lost 10 metres in altitude due to the near-continuous bombardment by guns of calibres of up to 420mm. Angelo Gatti, a staff officer in the supreme command, described his mounting despair: ‘I feel something collapsing inside me; I shall not be able to endure this much longer, none of us will; it is too gigantic, truly limitless, it will crush us all.’ The Austrians looked as if they had suffered a major defeat but, after Cadorna’s grimly pyrrhic victory, the tide was about to turn.
There are excellent British sources on the quality of the Italian artillery at this stage of the war. Lieutenant Hugh Dalton served with the B2 Heavy Artillery Group assigned to the Isonzo sector while Lieutenant-Colonel Archibald Moberly commanded B1 Heavy Artillery Group. Dalton was particularly impressed with the individual technical skills of the Italian artillery and their incomparable mountain engineers but noted that local commanders were very keen to secure Royal Artillery support. While the total number of shells appears impressive on the Isonzo Front, Dalton noticed that the ammunition levels were lower than those in France and Flanders and noted that this was reflected in the rates of fire, RA ‘ordinary’ rate being 30 rounds per hour, five times Italy’s fuoco normale. Dalton also noted that the proportion of heavy guns was one quarter of what he had experienced in France. The abundance of good observation post sites astonished the Royal Artillery officers. Depending on the sector, there were kavernen, mountain huts or treetop hides, all under cloudless skies. Such luxury delighted one of Dalton’s colleagues, who gleefully described Italy as a ‘gunner’s heaven’. The no. 101 fuse was almost as effective as the no. 106 in Italy due to the impact advantage of hitting solid rock. Wire-clearing was relatively simple but a great deal of fire was required to destroy rockhewn trenches or kavernen – Moberly and his Italian colleagues naturally preferred enfilade fire to lobbing shells straight into the enemy’s defensive line and both Dalton and Moberly were impressed by the ‘man-killing’ effect of high explosive in the mountains (as at Gallipoli, the rocky terrain increased the effectiveness of the artillery).
Moberly was equally impressed by the Italian engineers but rather less impressed with the higher levels of command. The lack of telephone wire for communications surprised him, particularly as the observations posts that had so impressed Dalton tended to be distant from the battery and thus required even more wire than usual. Italian HAG equivalents, the raggruppamenti, were allotted to sectors, not to particular assault or defensive units, and Moberly was surprised by the fact that there was no expectation that he would meet with the commander of the division he was supporting. During the first operation supported by B1, Moberly noted the Italians were still grappling with technical issues that had been identified and solved on the Western Front years before, particularly regarding communication between the assault units and the supporting artillery, a situation aggravated by the smoke and dust created by the bombardment obscuring the target. He was also troubled by the lack of specific missions assigned to his men and the concentration on planned but uncoordinated support for attacks.
Moberly noted that the ineffectiveness of Italian counter-battery fire was due to the HAGs assigned to the task being allocated to army and not corps command and thus lacking tactical coordination in the battles. As a result the counter-battery staff soon lost touch with the progress of the battle and found it difficult to coordinate fire. Moberly even received orders to shell positions that his own observation posts had reported as silent for days. Commando Supremo had made counter-battery work a priority for ammunition allocation, but had not realised that numbers did not equal results. Counter-battery orders criss-crossed the chain of command, bypassing the heavy artillery raggruppamenti and going to the field artillery groupes, a system that naturally led to some confusion and to errors that made counter-battery fire ineffective. Attempts to solve problems created others: the deliberate simplification of orders, for example, speeded up their transmission across scratchy telephone lines, but sometimes led to requests for a handful of shells so even a timely request lacked enough power. The only aspect that impressed Moberly was that counter-battery officers spent four days out of every eight at front-line observation posts and thus established a close relationship with the Forward Observation Officers.