Editing Battle of Passchendaele (section)

===September–October===

{{main|Western Front tactics, 1917#The British set-piece attack, late 1917|l1 = The British set-piece attack, late 1917}}

[[File:The Battle of Passchendaele, July-november 1917 Q6416.jpg|thumb|{{centre|Derelict tank used as the roof of a dug out, Zillebeke, 20 September 1917 (Q6416)}}]]
The [[4th Army (German Empire)|4th Army]] had held on to the Gheluvelt Plateau in August but its casualties worsened the German manpower shortage.{{sfn|Sheldon|2007|pp=119–120}} Haig transferred the main offensive effort to the Second Army on 25 August and moved the northern boundary of the Second Army closer to the Ypres–Roulers railway. More heavy artillery was sent to Flanders from the armies further south and placed opposite the Gheluvelt Plateau.{{sfn|Nicholson|1964|p=308}} Plumer continued the tactical evolution of the Fifth Army during its slow and costly progress in August. After a pause of about three weeks, Plumer intended to capture the plateau in four steps, with six-day intervals to bring forward artillery and supplies.{{sfn|Edmonds|1991|p=237}} The Second Army attacks were to remain limited and infantry brigade tactics were changed to attack the first objective with a battalion each and the final one with two battalions, the opposite of the Fifth Army practice on 31 July, to adapt to the dispersed defences being encountered between the {{lang|de|Albrechtstellung}} and the {{lang|de|Wilhelmstellung}}.{{sfn|Marble|2003|loc=App 22}}

Plumer arranged for the medium and heavy artillery reinforcements reaching Flanders to be added to the creeping bombardment, which had been impossible with the amount of artillery available to the Fifth Army.{{sfn|Marble|2003|loc=App 22}} The tactical changes ensured that more infantry attacked on narrower fronts, to a shallower depth than on 31 July, like the Fifth Army attacks in August. The shorter and quicker advances possible once the ground dried were intended to be consolidated on tactically advantageous ground, especially on any reverse slopes in the area, with the infantry still in contact with the artillery and aircraft, ready to repulse counter-attacks.{{sfn|Nicholson|1964|p=308}} The faster tempo of operations was intended to add to German difficulties in replacing tired divisions through the railway bottlenecks behind the German front.{{sfn|Edmonds|1991|pp=236–242}} The pause in British attacks misled some of the German commanders and Albrecht von Thaer, the chief of staff of {{lang|de|Gruppe Wijtschate}}, wrote that it was "almost boring".{{sfn|Liddle|1997|pp=45–58}} Kuhl doubted that the offensive had ended but had changed his mind by 13 September; two divisions, thirteen heavy artillery batteries, twelve field batteries, three fighter squadrons and four other units of the {{lang|de|Luftstreitkräfte}} were transferred from the 4th Army.{{sfn|Terraine|1977|p=257}}

====German tactical changes====

{{main|Western Front tactics, 1917#German defensive changes, late 1917|l1=German defensive changes, late 1917}}

After setting objectives {{cvt|1|–|2|mi}} distant on 31 July, the British attempted shorter advances of approximately {{cvt|1500|yd}} in August but were unable to achieve these lesser objectives in the south of the battlefield, because the rain soaked ground and poor visibility were to the advantage of the defenders. After the dry spell in early September, British advances had been much quicker and the final objective was reached a few hours after dawn, which confounded the German counter-attack divisions. Having crossed {{cvt|2|mi}} of mud, the {{lang|de|Eingreif}} divisions found the British already dug in, with the German forward battle zone and its weak garrison gone beyond recapture.{{sfn|Wynne|1976|p=303}} In August, German front-line divisions had two regiments deployed in the front line, with the third regiment in reserve. The front battalions had needed to be relieved much more frequently than expected due to the power of British attacks, constant artillery-fire and the weather. Replacement units became mixed up with ones holding the front and reserve regiments had failed to intervene quickly, leaving front battalions unsupported until {{lang|de|Eingreif}} divisions arrived some hours later.{{sfn|Rogers|2010|p=168}}

In July and August, German counter-attack ({{lang|de|Eingreif}}) divisions had conducted an "advance to contact during mobile operations", which had given the Germans several costly defensive successes.{{sfn|Sheldon|2007|p=184}} After the [[Battle of the Menin Road Ridge]], German tactics were changed.{{sfn|Rogers|2010|p=168}} After another defeat on 26 September, the German commanders made more tactical changes to counter the more conservative form of limited attacks adopted by the British.{{sfn|Sheldon|2007|p=184}} German counter-attacks in September had been "assaults on reinforced field positions", due to the restrained nature of British infantry advances. The fine weather in early September had greatly eased British supply difficulties, especially in ammunition and the British made time to establish a defence in depth on captured ground, protected by standing artillery barrages. The British attacked in dry, clear conditions, with more aircraft over the battlefield for counter-attack reconnaissance. It had also been found in 1916 that corps headquarters had become aware of the situation from the reports of aircrew on contact-patrol, where reconnaissance aircraft flew low over the battlefield to map the positions of British troops.{{sfn|Jones|2002|p=173–175}} Brigade headquarters had been ignorant of events and arrangements were made for the swift transmission of information forwards. Systematic defensive artillery-fire was forfeited by the Germans, due to uncertainty over the position of their infantry, just when the British infantry benefited from the opposite. German counter-attacks were costly failures and on 28 September, Thaer wrote that the experience was "awful" and that he did not know what to do.{{sfnm|1a1=Edmonds|1y=1991|1pp=294–295|2a1=Liddle|2y=1997|2pp=45–58}}

Ludendorff ordered the {{lang|de|Stellungsdivisionen}} (ground holding divisions) to reinforce their front garrisons; all machine-guns, including those of the support and reserve battalions were sent into the forward zone, to form a cordon of four to eight guns every {{cvt|250|yd}}.{{sfn|Wynne|1976|pp=307–308}} The {{lang|de|Stellungsdivisionen}} were reinforced by the {{lang|de|Stoß}} (shock) regiments of {{lang|de|Eingreif}} divisions, which were moved into the artillery protective line behind the forward battle zone, to counter-attack sooner. The other regiments of the {{lang|de|Eingreif}} divisions were to be held back and used for a methodical counter-attack ({{lang|de|Gegenangriff}}) a day or two after and for spoiling attacks as the British reorganised.{{sfnm|1a1=Sheldon|1y=2007|1pp=190–191|2a1=Wynne|2y=1976|2p=307}}{{efn|The [[4th Guards Infantry Division (German Empire)|4th Guard Division]], [[4th Royal Bavarian Division|4th Bavarian Division]], [[6th Royal Bavarian Division|6th Bavarian Division]], [[10th Ersatz Division (German Empire)|10th Ersatz Division]], [[16th Division (German Empire)|16th Division]], [[19th Reserve Division (German Empire)|19th Reserve Division]], [[20th Division (German Empire)|20th Division]], 187th Division, 195th Division and [[45th Reserve Division (German Empire)|45th Reserve Division]] took part in the battle.{{sfn|USWD|1920}}}} More tactical changes were ordered on 30 September; operations to increase British infantry losses were to continue and gas bombardments were to be increased, weather permitting. Every effort was to be made to induce the British to reinforce their forward positions with infantry for the German artillery to bombard them.{{sfn|Sheldon|2007|pp=184–186}} Between 26 September and 3 October, the Germans attacked at least {{nowrap|24 times}} and Operation High Storm {{lang|de|Unternehmen Hohensturm}}, a {{lang|de|Gegenangriff}} (methodical counter-attack), to recapture the area around Zonnebeke was planned for 4 October.{{sfnm|1a1=Terraine|1y=1977|1p=278|2a1=Prior|2a2=Wilson|2y=1996|2p=135}}

====Battle of the Menin Road Ridge====

{{Main|Battle of the Menin Road Ridge}}

[[File:Battle of Menin Road - wounded at side of the road.jpg|thumb|{{centre|Wounded men at the side of a road after the Battle of Menin Road}}]]
The British plan for the battle fought from {{nowrap|20 to 25 September,}} included more emphasis on the use of heavy and medium artillery to destroy German concrete pill-boxes and machine-gun nests, which were more numerous in the battle zones being attacked, than behind the original July front line and to engage in more counter-battery fire. The British had {{nowrap|575 heavy}} and medium and {{nowrap|720 field}} guns and howitzers, more than double the quantity of artillery available at the Battle of Pilckem Ridge.{{sfn|Edmonds|1991|pp=238–239}} Aircraft were to be used for systematic air observation of German troop movements, to avoid the failures of previous battles, where too few aircrews had been burdened with too many duties and had flown in bad weather, which made their difficulties worse.{{sfn|Jones|2002|p=181}}

On 20 September, the Allies attacked on a {{cvt|14500|yd|mi+km}} front and by mid-morning had captured most of their objectives, to a depth of about {{cvt|1500|yd}}.{{sfn|Terraine|1977|p=261}} The Germans made many hasty counter-attacks ({{lang|de|Gegenstoße}}), beginning around {{nowrap|3:00&nbsp;p.m.}} until early evening, all of which failed to gain ground or made only a temporary penetration of the new British positions. The German defence had failed to stop a well-prepared attack made in good weather.{{sfn|Harris|2008|p=366}} Minor attacks took place after 20 September, as both sides jockeyed for position and reorganised their defences. A mutually-costly attack by the Germans on 25 September, recaptured pillboxes at the south western end of Polygon Wood. Next day, the German positions near the wood were swept away in the Battle of Polygon Wood.{{sfn|Sheldon|2007|p=165}}

====German counter-attack, 25 September====

{{main|Action of 25 September 1917}}

Two regiments of the German [[50th Reserve Division (German Empire)|50th Reserve Division]] attacked on a {{cvt|1800|yd}} front, either side of the Reutelbeek stream, supported by aircraft and {{nowrap|44 field}} and {{nowrap|20 heavy}} batteries of artillery, four times the usual amount for a division. The German infantry managed to advance on the flanks, about {{cvt|100|yd}} near the Menin road and {{cvt|600|yd}} north of the Reutelbeek. The infantry were supported by artillery-observation and ground-attack aircraft; a box-barrage was fired behind the British front-line, which isolated the British infantry from reinforcements and ammunition. Return-fire from the [[33rd Division (United Kingdom)|33rd Division]] and the [[15th Brigade (Australia)|15th Australian Brigade]] of the [[5th Division (Australia)|5th Australian Division]] along the southern edge of Polygon Wood to the north, forced the attackers under cover around some of the {{lang|de|Wilhelmstellung}} pillboxes, near Black Watch Corner, at the south-western edge of Polygon Wood. German attempts to reinforce the attacking troops failed, due to British artillery observers isolating the advanced German troops with artillery barrages.{{sfn|Edmonds|1991|pp=282–284}}

Plumer ordered the attack due on 26 September to go ahead but reduced the objectives of the 33rd Division. The 98th Brigade was to advance and cover the right flank of the 5th Australian Division and the 100th Brigade was to re-capture the lost ground further south. The 5th Australian Division advance the next day began with uncertainty as to the security of its right flank; the attack of the depleted 98th Brigade was delayed and only managed to reach Black Watch Corner, {{cvt|1000|yd}} short of its objectives. Reinforcements moved into the 5th Australian Division area and attacked south-westwards at noon as a silent (without artillery support) frontal attack was made from Black Watch Corner, because British troops were known to be holding out in the area. The attack succeeded by {{nowrap|2:00&nbsp;p.m.}} and later in the afternoon, the 100th Brigade re-took the ground lost north of the Menin road. Casualties in the 33rd Division were so great that it was relieved on 27 September by the 23rd Division, which had only been withdrawn on the night of {{nowrap|24/25 September.}}{{sfn|Edmonds|1991|pp=286–287}}

====Battle of Polygon Wood====

{{Main|Battle of Polygon Wood}}

[[File:Australian infantry small box respirators Ypres 1917.jpg|thumb|upright|{{centre|Australian infantry with [[small box respirator]] gas masks, Ypres, September 1917}}]]
The Second Army altered its Corps frontages soon after the attack of 20 September, for the next effort {{nowrap|(26 September – 3 October)}} so that each attacking division could be concentrated on a {{cvt|1000|yd}} front. Roads and light railways were extended to the new front line, to allow artillery and ammunition to be moved forward. The artillery of [[VIII Corps (United Kingdom)|VIII Corps]] and [[IX Corps (United Kingdom)|IX Corps]] on the southern flank, simulated preparations for attacks on Zandvoorde and Warneton. At {{nowrap|5.50&nbsp;a.m.}} on 26 September, five layers of barrage fired by British artillery and machine-guns began. Dust and smoke thickened the morning mist and the infantry advanced using compass bearings.{{sfn|Edmonds|1991|p=284}} Each of the three German ground-holding divisions attacked on 26 September had an {{lang|de|Eingreif}} division in support, twice the ratio of 20 September. No ground captured by the British was lost and German counter-attacks managed only to reach ground to which survivors of the front-line divisions had retired.{{sfn|Edmonds|1991|p=293}}