The Battle of Polygon Wood (26 September to 3 October 1917) was fought during the second part of the Third Battle of Ypres in the First World War. The battle was fought near Ypres in Belgium, from the Menin road to Polygon Wood and thence north, to the area beyond St Julien. Much of the woodland had been destroyed by the huge bombardments from both sides since 16 July and the area had changed hands several times.
General Herbert Plumer continued the British general attacks with limited objectives. Lines of skirmishers advanced ahead of small infantry columns in depth (as had been adopted by the Fifth Army in August) with a vastly increased amount of artillery support, five layers of creeping barrage on the Second Army front. An advance of was planned, to stop on reverse slopes, which were easier to defend, enclosing ground which gave observation of German reinforcement routes and counter-attack assembly areas.
Preparations swiftly to defeat German counter-attacks were made, by mopping-up and consolidating the captured ground with defences in depth. The attack inflicted a severe blow on the German 4th Army, causing many casualties and capturing a large part of , the fourth German defensive position, threatening the German hold on Broodseinde ridge.
The drier weather continued to benefit the British attackers by solidifying the ground and causing early morning mists that obscured British infantry attacks at dawn. The mist cleared during the morning and revealed German (counter-attack) formations to air and ground observation, well in advance of their arrival on the battlefield. German methodical counter-attacks () from 27 September to 3 October failed and German defensive arrangements were changed hastily after the battle to try to counter British offensive superiority.
Background
Tactical developments
The preliminary operation to capture Messines ridge had been followed by a strategic pause as the British repaired their communications behind Messines ridge, completed the building of the infrastructure necessary for a much larger force in the Ypres area and moved troops and equipment north from the Arras front. After delays caused by local conditions, the Battles of Ypres had begun on 31 July with the Battle of Pilckem Ridge, which was a substantial local success for the British, taking a large amount of ground and inflicting many casualties on the German defenders. The Germans had recovered some of the lost ground in the middle of the attack front and restricted the British advance on the Gheluvelt Plateau further south. British attacks had then been seriously hampered by unseasonal heavy rain during August and had not been able to retain much of the additional ground captured on the plateau on 10, 16–18, 22–24 and 27 August due to the determined German defence, mud and poor visibility.
Haig ordered artillery to be transferred from the southern flank of the Second Army and more artillery to be brought into Flanders from the armies further south, to increase the weight of the attack on the Gheluvelt Plateau. The principal role was changed from the Fifth to the Second Army and the boundary between the two armies was moved north towards the Ypres–Roulers railway, to narrow the frontages of the Second Army divisions on the Gheluvelt Plateau. A pause in British attacks was used to reorganise and to improve supply routes behind the front line, to carry forward of ammunition above normal expenditure. Guns were moved forward to new positions and the infantry and artillery reinforcements practised for the next attack.
The unseasonal rains stopped, the ground began to dry and the cessation of British attacks misled the Germans, who risked moving some units away from Flanders. The offensive had resumed on 20 September with the Battle of the Menin Road Ridge, using similar step-by-step methods to those of the Fifth Army after 31 July, with a further evolution of technique, based on the greater mass of artillery made available to enable the consolidation of captured ground with sufficient strength and organisation to defeat German counter-attacks. Most of the British objectives had been captured and held, with substantial losses being inflicted on the six German ground-holding divisions and their three supporting divisions. British preparations for the next step began immediately and both sides studied the effect of the battle and the implications it had for their dispositions.
Prelude
British preparations
+Weather20–27 September 1917 Date Rainmm °F 200.066dull 210.062dull 220.063fine 230.065fine 240.074dull 250.075mist 260.568mist 270.067dull
On 21 September, Haig instructed the Fifth Army (General Hubert Gough) and Second Army (General Herbert Plumer) to make the next step across the Gheluvelt Plateau, on a front of . The I Anzac Corps (Lieutenant-General William Birdwood) would conduct the main advance of about , to complete the occupation of Polygon Wood and the south end of Zonnebeke village. The Second Army altered its corps frontages soon after the attack of 20 September to reduce the divisional frontages to . Roads and light railways were built behind the new front line to move artillery and ammunition forward, beginning on 20 September; in fine weather this was finished in four days. As before Menin road, bombardment and counter-battery fire began immediately, with practice barrages fired daily as a minimum. Artillery from the VIII Corps (Lieutenant-General Sir Aylmer Hunter-Weston) and IX Corps (Lieutenant General Alexander Hamilton-Gordon) in the south conducted bombardments to simulate attack preparations on Zandvoorde and Warneton. Haig intended that later operations would capture the rest of the ridge from Broodseinde, giving the Fifth Army scope to advance beyond the ridge north-eastwards and allow the commencement of Operation Hush.
The huge bombardments from both sides had cut up the ground and destroyed roads. New road circuits were built to carry supplies forward, especially artillery ammunition. Heavier equipment bogged in churned mud and had to be brought forward by wagons along roads and tracks, many of which were under German artillery observation from Passchendaele ridge, rather than being moved cross-country. The I Anzac Corps had guns, one for every of front and many field artillery brigades with 18-pounder guns and 4.5-inch howitzers, that with the guns of the other attacking corps, were moved forward from 20 to 24 September. Assembled forward of the artillery were Vickers machine-guns of the divisional machine-gun companies, the creeping machine-gun barrage and guns for emergency barrages against German counter-attacks and to increase the barrage towards the final objective.
The frontages of VIII and IX Corps were moved northwards so that X Corps (Lieutenant-General Thomas Morland) could take over of front up to the southern edge of Polygon Wood, which kept the frontages of the two Australian divisions of I Anzac Corps to . The 39th Division took over from the 41st Division, ready to attack Tower Hamlets (at the top of the Bassevillebeek spur), the 33rd Division replaced the 23rd Division beyond the Menin road and the 5th Australian Division and the 4th Australian Division replaced the 1st Australian Division and the 2nd Australian Division in Polygon Wood. The Action of 25 September 1917 took place between the Menin road and Polygon Wood as the 33rd Division was taking over from the 23rd Division. For a time the German attack threatened to delay preparations for the British attack due the next day. Some ground was captured by the Germans and part of it was then recaptured by the 33rd Division. Plumer ordered that the flank guard protecting the I Anzac Corps on 26 September be formed by the 98th Brigade of the 33rd Division while the 100th Brigade recaptured the lost ground.
Plan
Dispersed and camouflaged German defences, using shell-hole positions, pillboxes, with much of the German infantry held back for counter-attacks, meant that as British units advanced and became weaker and disorganised by losses, fatigue, poor visibility and the channelling effect of waterlogged ground, they met more and fresher German defenders. The German defensive system had been more effective in the unusually rainy weather in August, making movement much more difficult and forcing the British to keep to duckboard tracks, easy to identify and bombard. Objectives were chosen to provide the British infantry with good positions from which to face German counter-attacks, rather than to advance with unlimited objectives. The Fifth Army had set objectives much closer than after 31 July and the Second Army methods of September were based on SS 144 The Normal Formation for the Attack (February 1917), reflecting the experience of the fighting in August and to exploit opportunities made possible by the reinforcement of the Flanders front with another before 20 September.
The methods based on the Second Army Note of 31 August had proved themselves on 20 September and were to be repeated. The extra infantry made available, by increasing the number of divisions and narrowing attack frontages, had greater depth than the August attacks. The leading waves of infantry were lightly equipped, further apart and followed by files or small groups ready to swarm around German defences uncovered by the skirmish lines. Each unit kept a sub-unit in close reserve, brigades a reserve battalion, battalions a reserve company and companies a reserve platoon. The manual (February 1917) reiterated the platoon organisation laid down in and recommended an attacking frontage of for a battalion, with wide intervals between each man, line and wave, to create a dispersed attack in depth. Where one or two objectives were to be captured, the first wave should advance to the final objective, with troops in following waves to mop-up and occupy the captured ground. Where more objectives were set, the first wave was to stop at the first objective, mop-up and dig in, ready to receive German counter-attacks, as following waves leapfrogged beyond them to the further objectives and did the same, particularly when enough artillery was present to provide covering fire for all of the depth of the attack.
The leap-frog method was chosen for the September attacks, whereas in July and August both methods had been used. Intermediate objectives closer to the front line were selected and the number of infantry attacking the first objective was reduced, since the German garrisons in the forward defended areas were small and widely dispersed. A greater number of units leapfrogged through to the next objective and the distance to the final objective was further reduced, to match the increasing density of German defences; the creeping barrage slowed as it moved towards the final objective. Particular units were allotted to mop-up and occupy areas behind the most advanced troops, to make certain that pockets of Germans overrun by the foremost troops were killed or captured, before they could emerge from shelter and re-join the battle. Increased emphasis was placed on Lewis-guns, rifle-fire and rifle-grenades. Hand-grenades were given less emphasis in favour of more rifle training. The proportion of smoke ammunition for rifle grenades and Stokes mortars was increased, to blind the occupants of German pillboxes as they were being surrounded. All units were required to plan an active defence against counter-attack, using the repulse of German infantry as an opportunity to follow up and inflict more casualties.