German defences The German front line regiments in the (Wytschatete arc/salient) held areas wide with one (the , battle battalion) forward, a second (, readiness battalion) in support and the third (, rest battalion) in reserve back. About posts per regimental sector were dispersed around the defensive zone. The German defence was intended to be mobile and in
Ic the third breastwork, were to conduct immediate counter-attacks to recapture
Ia and
Ib. If they had to fall back, the support battalions would advance to restore the front system, except at Spanbroekmolen, which due to its importance was to be held at all costs (). (General
Maximilian von Laffert) held Wytschaete with the 2nd Division on a front of ; the front position was lightly held, with strongpoints distributed up to back. At the end of May, British artillery fire was so damaging that the relief of the 2nd Division was promised for June. was substantially reinforced with artillery, ammunition and aircraft and the 35th and 3rd Bavarian divisions, which had been trained as (specialist counter-attack divisions), were used to relieve the and to replace them, two divisions were transferred from , which did not know the area and had no training. The preliminary bombardment began on 8 May and intensified on 23 May. The breastworks of the front position trenches were demolished and concrete shelters on both sides of the ridge were systematically destroyed. Air superiority allowed the British artillery observation aircraft to cruise over the German defences, despite the efforts of
Jagdgeschwader 1 (JG 1, the Richthofen Circus) of the . On 26 May, the German front garrisons were ordered to move forward into shell-holes in no man's land at dawn and return to their shelters at night. When the shelters were destroyed, the shell-hole positions were made permanent, as were those of the support companies further back. Troops in the were withdrawn behind the ridge and by the end of May, the front battalions were being relieved every two days instead of every five, to maintain their battle-worthiness. The village of Wytschaete was on the summit of the ridge and the main defensive position at the north end of the plateau, having been fortified and prepared for all-round defence. A line of trenches traced the edge of the village and an inner line went round the houses at the village square and the church. The most formidable part of the defences were machine-gun nests in emplacements and house cellars along the western fringe of the village. Some troops on the ridge were convinced that their positions had been undermined and their morale was depressed further by a prisoner taken on 6 June, who said that the attack would be synchronised with mine explosions. On 1 June, the British bombardment became more intense and nearly every German defensive position on the forward slope was obliterated. British heavy and super-heavy artillery bombardments Wytschaete on 3 June and were followed up by a gas bombardment from the field artillery, which smashed many of the defensive positions in the village. Infantry Regiment 44 lost 57 men killed and 198 wounded from 1 to 6 June, Grenadier Regiment 4 and Fusilier Regiment 33 having about the same number of casualties each. The German air effort reached its maximum from when German aircraft observed counter-battery shoots. Wireless interception by the British showed that German aircraft escorted by up to seven fighters each, were directing the German artillery reply against the Second Army. British air observation on the reverse slope was less effective than in the foreground but Messines and Wytschaete villages were demolished, as were much of the and (Oosttaverne Line) although many pill boxes survived. Long-range fire on Comines, Warneton, Wervicq, smaller villages, road junctions, railways and bridges caused much damage and several ammunition dumps were destroyed.
British preparations The British had begun to mine under Messines Ridge in 1916; sappers tunnelled into a layer of
blue clay below the surface, then drifted galleries to points deep underneath the German front position. Canadian, Australian, New Zealand and British miners laid
26 mines with of
ammonal explosive. On the right flank of the 36th (Ulster) Division the 107th Brigade faced three mines at Kruisstraat and north was the larger Spanbroekmolen mine. The mine close to Peckham House was opposite the 109th Brigade on the left flank. The 47th Brigade of the 16th (Irish) Division was to advance into the area of the Maedelstede mine and the 49th Brigade past two at Petit Bois. On the left of the 16th (Irish) Division, the 19th (Western) Division was also to advance with the assistance of mines north of Wytschaete. The Second Army devised a centralised artillery plan of great sophistication, using field survey, gun
calibration, weather data and a new and highly accurate map, to increase the accuracy of British artillery. Wire cutting bombardments had to destroy about of barbed wire and using the new methods, all German guns within of the attack front were to be neutralised. Methodical target-finding with new sound-ranging equipment, better organisation of flash-spotting and the centralisation of command at a new Army Report Centre, based at Locre Château were introduced. Second Army
counter-battery artillery bombardments increased from twelve in the week ending 19 April, to in the last ten days before the attack. IX Corps arranged four counter-battery groups, each with one heavy artillery group and five bombardment groups, one for each of its three attacking divisions and two (with the heaviest howitzers) in reserve. A Heavy Artillery Group Commander was attached to each divisional artillery headquarters, to command the heavy artillery once the infantry attack began. The IX Corps field artillery groups and sub-groups were formed to have an artillery liaison officer for every infantry brigade, with two sub-groups, one with six batteries and one with six batteries. Surplus field artillery brigade headquarters planned forward moves for the guns and were kept ready to replace casualties. It was expected that much of the artillery would need to switch rapidly from bombardment to engaging German counter-attacks and divisional
Forward Observation Officers (FOOs) were to control the artillery which had remained in place. The reserve divisions due to advance to the Oosttaverne Line would control artillery hidden close to the front line and the guns moved forward into no man's land. Two thirds of the were to fire a
creeping barrage of
shrapnel immediately ahead of the advance, while the remainder of the
field guns and howitzers were to fire a standing barrage, further ahead on German positions and lift to the next target, when the infantry came within of the barrage. Each division was given four extra batteries of field artillery, which could be withdrawn from the barrage at the divisional commander's discretion to engage local targets. The field batteries of the three reserve divisions were placed in camouflaged positions, close to the British front line. As each objective was taken by the infantry, the creeping barrage was to pause ahead and become a standing barrage, while the infantry consolidated. During this time the pace of fire was to slacken to one round per-gun per-minute, allowing the gun-crews a respite, before resuming full intensity as the barrage moved on. The heavy and super-heavy artillery was to fire on German artillery positions and rear areas and were to fire a barrage over the heads of the advancing troops. In the week up to 7 June, and
howitzers bombarded the German trenches, cut wire, destroyed strong-points and conducted
counter-battery fire against the guns opposite, using The intensity of bombardment in the salient began to increase on 8 May, wire cutting began on 21 May and an extra two days were added to the bombardment for more counter-battery fire. The general bombardment intensified again from 23 May, smashing the German breastworks in the first position and the pillboxes on the forward slope. The main bombardment began on 31 May, with only one day of poor weather before the attack and until the infantry advance, more than 3,000,000 shells were fired on a front. The attack barrage was rehearsed on 3 June to allow British air observers to plot masked German batteries, which mainly remained hidden but many minor flaws in the British barrage were reported. A repeat performance on 5 June induced a larger number of hidden German batteries to open fire and reveal themselves. Wytschaete was subjected to a special super-heavy bombardment and the garrison from Grenadier Regiment 4 reported that the village was smashed by columns of shells dropping onto the village.
Air operations Two flights of each artillery-observation squadron concentrated on counter-battery observation and one became a bombardment flight, working with particular artillery bombardment groups for wire-cutting and trench-destruction; when the attack began, these flights undertook contact-patrols to observe the positions of British troops. German artillery positions and the were on the reverse slope and not visible to British ground observers. For observation over the rear slopes of the ridge, were concentrated in II Brigade RFC and eight balloons of II Kite Balloon Wing were placed behind the British front line. British fighter aircraft tried to prevent German aircraft observing for their artillery, by dominating the air from the British front line to the German balloon line, about beyond. The "barrage line" was patrolled all day for the week before the attack by fighters at , with more at in the centre of the attack front. The weather was
fair or
fine except for , when it was
very bad). No British corps aircraft were shot down by German aircraft until 7 June, when aircraft were directing artillery fire simultaneously. Behind the British barrage line was a second line of defence, which used wireless interception to take bearings on German artillery observation aircraft and guide British aircraft into areas where German flights were most frequent. Aeroplane compass stations and an aeroplane intercepting station, were linked by telephone to the army wing headquarters, fighter squadrons, the anti-aircraft commander and the corps heavy artillery headquarters. Areas threatened by German bombardment could be warned, German artillery-observation aircraft could be attacked and German artillery batteries fired on, when they revealed themselves. From , II Brigade had through wireless interception, shot down one German aircraft, damaged seven and stopped artillery bombardments. Normal offensive patrols continued beyond the barrage line out to Ypres to Roulers and Menin, where after German air reinforcements had arrived, large formations of British and German aircraft clashed in long
dogfights. Longer-range bombing and reconnaissance flights concentrated on German-occupied airfields and railway stations; the night bombing specialists of
100 Squadron attacked trains around Lille, Courtrai, Roulers and Comines. Two squadrons were reserved for close air support on the battlefield and low attacks on German airfields. There was a thunderstorm in the evening of 6 June but by midnight the sky had cleared and at British aircraft cruised over the German lines, to camouflage the sound of tanks as they drove to their starting points.
IX Corps preparations The 2nd Field Survey Company (2nd FSC) set up W Section for sound-ranging in the IX Corps sector, which provided targeting information for the corps counter-battery artillery. Communication was to be by visual means,
messenger pigeon, wireless,
Fullerphone, runners and SOS rockets. Two cable lines up to the front line were buried by the
Royal Engineers Signal Service for the Fullerphones and advanced bases were chosen in the German lines at Spanbroekmolen and Peckham, to be connected by armoured cables across no man's land. When the infantry reached the final objective the advanced stations were to move up to the crest of the ridge. Brigade intelligence sections were to set up observation posts at Spanbroekmolen and Peckham and battalion intelligence sections were to follow their battalions and find places to observe the infantry up to the final objective and send scouts to contact flanking battalions and establish the situation. A divisional signal station was installed on Kemmel Hill in line of sight with the brigade advanced sections to communicate via Lucas lamp. Attack training took place on ground marked to show the German defences and officers of flanking battalions attended training sessions to ensure that plans were compatible. A scale model of the ridge was built by the IX Corps Chief Engineer on the Scherpenberg Hill between
Locre and
La Clytte, with boards around the edges for about a company of men to examine the model together. To assist with communication a message map was devised with the map on one side and a form on the other containing a list of the information needed by the recipient to act on it. Supply dumps for the 36th, 16th and 19th divisions were established at Lindenhoek crossroads, on the Lindenhoek–Neuve Eglise road and beyond these was an advanced dump a brigade dump and one for each of the six attacking battalions. A pack-transport system and packs for carriers were issued, along with plans to carry up a hot meal to the front line on the midnight before the attack. Oranges, Oxo cubes, chewing-gum and lime juice were issued to each man and every fourth man had a tin of solidified alcohol for
cooking. The 16th (Irish) Division began training for the attack in April, the 49th Brigade rehearsing over a replica of the ground around Wytschaete, during which the junior officers were put under great pressure to perform. The division used the model of Messines Ridge near the Scherpenberg for everyone to become familiar with Wytschaete and the vicinity; the model was adapted to every German alteration to the defences as the British artillery smashed some and the Germans dug others. The division patrolled and raided almost nightly to gather information; a raid on 27 May consisting of took killed troops and lifted many valuable documents and reconnaissance photographs, for On 4 June, raided Wytschaete Wood, killed and captured From the 16th (Irish) divisional artillery
18-pounder field gun shells
4.5-inch howitzer rounds beyond the divisional sector from Maedelstaede Farm to the Vierstraat–Wytschaete road. The attack was to be conducted by the 47th Brigade and the 49th Brigade, in which each brigade would attack on a two-battalion front, with two battalions in support, the 48th Brigade and a brigade of the 11th Division being held in reserve.
IX Corps Plan IX Corps (Lieutenant-General Sir
Alexander Hamilton-Gordon) was to attack Wytschaete with the
36th (Ulster) Division and
16th (Irish) Division, supported by of the II Brigade, Heavy Branch
Machine-Gun Corps and the
11th (Northern) Division in reserve. IX Corps had three intermediate objectives, where fresh infantry would
leap-frog through the troops on the objective to continue the advance to the next objective, followed by an advance down the far slope in the afternoon. IX Corps was to attack on a front, which tapered to on the plateau. At the mines would be detonated and the blue line (first objective) was to be occupied by followed by a two-hour pause. At the advance to the black line (second objective) would begin and consolidation was to start by Fresh troops from reserve would then pass through, to attack the Oosttaverne Line at As soon as the black line was captured, all guns were to bombard the Oosttaverne Line, conduct counter-battery fire and place a standing barrage beyond the black line, the in reserve would join the tanks still operational and join in the advance to the Oosttaverne Line. ==Battle==