Mud and flooded shell holes severely reduced the mobility of the infantry and poor visibility hampered artillery observers and the crews of artillery-observation aircraft.

Gough kept pressure on the 4th Army, to prevent the Germans from recovering and to enable Operation Hush on the coast, which needed the high tides due at the end of August.

[14] Training emphasised the need for units to "hug" the creeping barrage and to form offensive flanks, to assist neighbouring troops whose advance had been halted by the defenders.

[15] Operation Summer Night (Unternehmen Sommernacht) was a German methodical counter-attack (Gegenangriff) near Hollebeke in the Second Army area on the southern flank, which began at 5:20 a.m. on 5 August.

After a short bombardment, three companies of I Battalion, Infantry Regiment 62 of the 12th Division captured a slight rise 0.62 mi (1 km) north-east of Hollebeke, surprising the British, who fell back 87 yd (80 m).

The British gunners were hampered by low cloud and rain, which made air observation extremely difficult and shells were wasted on empty gun emplacements.

The appalling weather and costly defeats caused a slump in the morale of the British infantry; lack of replacements began to concern the German commanders.

[19] II Corps was to reach the green line of 31 July, an advance of about 4,430–4,920 ft (1,350–1,500 m) and form a defensive flank from Stirling Castle to Black Watch Corner.

[28] Au Bon Gite, the German blockhouse which had resisted earlier attacks, was to be dealt with by infantry from one of the covering battalions and a Royal Engineer Field Company.

[37][b] Eingreif divisions were accommodated 9,800–12,000 yd (5.6–6.8 mi; 9.0–11.0 km) behind the front line and at the beginning of an attack began their advance to assembly areas in the rückwärtige Kampffeld behind Flandern I Stellung, ready to intervene in the Grosskampffeld, for den sofortigen Gegenstoß (the instant-immediate counter-thrust).

[38][39] Opposite the French First Army (1re Armée), the Germans had counter-flooded the area between Dixmude and Bixschoote and fortified the drier ground around the waters to stop an attack across or around the floods.

[41] In an appreciation of 2 August, Gruppe Ypern correctly identified the Wilhelmstellung as the British objective on 31 July and predicted more attacks on the Gheluvelt Plateau and further north towards Langemarck.

In the 18th (Eastern) Division area, German machine-gun fire from pillboxes caused many losses to the 53rd Brigade, which was stopped in front of the north-west corner of Inverness Copse.

Providing carrying parties since the last week in July and holding ground from 4 August in the Hanebeek and Steenbeek valleys, which were overlooked by the Germans, had exhausted many men.

The advance began on time and after a few hundred yards encountered German strong points, which were found not to have been destroyed by a series of special heavy artillery bombardments before the attack.

[47] The 48th (South Midland) Division attacked at 4:45 a.m. with one brigade, capturing Border House and gun pits either side of the north-east bearing St Julien–Winnipeg road, where they were held up by machine-gun fire and a small counter-attack.

The advance continued to the final objective, which was reached and consolidated by 10:00 a.m. Patrols moved forward towards the Broombeek and a German counter-attack at 4:00 p.m., was stopped by artillery and small-arms fire.

[52] During the night of the 15/16 and the morning of 16 August, French aircraft bombed the German defences, bivouacs around Houthoulst Forest and Lichtervelde railway station 11 mi (18 km) away.

[41] I Corps crossed the Yperlee from the north-west of Bixschoote to north of the Drie Grachten bridge-head and drove the Germans out of part of the swampy Poesele peninsula but numerous pillboxes built in the ruins of farmhouses further back were not captured.

On the Poelsele peninsula the German defenders resisted until nightfall before being driven back, as the French closed up to the west bank of the Martjewaart reach of the Steenbeek.

[52] On 17 August, French heavy howitzers battered Les Lilas and Mondovi blockhouses all day and by nightfall both strong points had been breached and the garrisons captured.

From the southern edge of the inundations between Dixmude and Drie Grachten, the French line had been pushed forward to the west bank of the Steenbeek as far as the south end of St Janshoek.

French engineers had worked in the swamps and morasses to repair roads, bridge streams and build wire entanglements, despite constant German artillery fire.

[54][c] Flash spotting to find the positions of German artillery was much more successful than in previous attacks and many more flares were lit by the infantry when called for by the crews of contact aeroplanes.

Army squadrons, Royal Naval Air Service (RNAS) and French aircraft flew over the lines and attacked German aerodromes, troops and transport as far as the weather allowed.

[60] German artillery fired continuously on a line from Stirling Castle to Westhoek and increased the rate of bombardment from noon, which isolated the attacking British battalions from reinforcements and supplies and prepared the counter-attack made in the afternoon.

[73][e] Tanks to help capture pillboxes had bogged down behind the British front-line and air support had been restricted by the weather, particularly by low cloud early on and by sending too few aircraft over the battlefield.

The 56th (1/1st London) Division recommended that advances be shortened, to give more time for consolidation and to minimise the organisational and communication difficulties caused by the muddy ground and wet weather.

Like Gough after 31 July, Plumer planned to launch a series of attacks with even more limited geographical objectives, using the extra heavy artillery brought in from the armies further south, to deepen and increase the weight of the creeping barrage.

[89] On 20 August, a special gas and smoke bombardment was fired by the British on Jehu Trench, beyond Lower Star Post, on the front of the 24th Division (II Corps).