The Bluff is a mound near St Eloi, south-east of Ypres in Belgium, created from a spoil heap made during the digging of the Ypres–Comines Canal before the war.

The German army still had many pre-war trained officers NCOs and soldiers; the British wartime volunteers gained experience in minor tactics but success usually came from firepower; in the underground war, the BEF tunnellers overtook the Germans in technological ability and ambition.

The general aspect south of Ypres is of low ridges and dips, gradually flattening to the north into a featureless plain.

The lowland west of the ridge was a mixture of meadows and fields, with high hedgerows dotted with trees, cut by streams and ditches emptying into canals.

[2] Spoil banks had been created during the digging of the Ypres–Comines Canal, connecting the Yser lowlands with the Lys river valley.

The canal cutting runs through a low point between Messines Ridge and the higher ground south-east of Ypres, about 1.5 mi (2.4 km) east of St Eloi and near Voormezele.

The Bluff was 30 ft (9.1 m) high, steep on the west side, with a gentle slope to the east and one of the best vantage points in the Ypres Salient.

[4] In the spring of 1915, there was constant underground fighting in the Ypres Salient at Hooge, Hill 60, Railway Wood, Sanctuary Wood, St Eloi and the Bluff, which required new drafts of British tunnellers for several months after the formation of the first eight Tunnelling companies of the Royal Engineers.

[4] In November, John Norton-Griffiths proposed to sink 20 or 30 shafts, about 50–70 yd (46–64 m) apart, into the blue clay from the Bluff to St Eloi.

[7] A bigger mine was detonated on the night of 21/22 January but all this achieved was a crater about 100 yd (91 m) wide, which the British occupied and made into another defensive position.

Reconnaissance flights by the new II Brigade Royal Flying Corps (RFC) were made more difficult by the bad winter weather but 6 Squadron managed to see enough to report that a German offensive was unlikely.

[9] The 51st Brigade held a 1,300 yd (1,200 m) front with three battalions and one in reserve, half kept ready for an immediate counter-attack if the Bluff was captured.

Trench mortar and howitzer fire, which was usual before an infantry attack led the defenders to request heavy artillery support.

[11] A platoon sent to replace the men trapped in The Tunnel was killed and the Bluff was captured, as were the front trenches of the 10th Sherwood.

[12] The 76th Brigade planned to attack against the width of the lost trenches at dusk, to have the maximum time for consolidation, preferably on 29 February.

[13] German artillery bombardments slowed the work; stormy weather and then snowfalls from 27 February outlined the new trenches and on 28 February, the attack was put back to 2 March, after the cold and snow ended with a thaw which turned the ground into slush; the following days were cold and wet with sleet and snow.

Pratt wanted a long preparatory bombardment and Brigadier-General Herbert Uniacke, the corps artillery commander, proposed a surprise attack with no preliminary artillery-fire.

[15] As the front line curved eastwards north of the 17th (Northern) Division, four heavy guns were dug in and camouflaged on Observatory Ridge, to fire along the Germans trenches during the attack.

The German sentries at the Bluff were found under cover, expecting the artillery salvo after the usual two-minute pause and the rest of the garrison was in dug-outs in the western face of the large crater.

Parties which ventured further forward suffered many casualties and the survivors were pulled back to the objective where consolidation began.

[20] The raiders blew in the gallery in no man's land that led to the Bluff but those from the 172nd Tunnelling Company were killed by machine-gun fire.

The German artillery reply began at 9:30 a.m. but the intense fire did not begin until 11:00 a.m., by when the British had emptied their front line and made rapid progress in consolidation.

The German artillery continued a high rate of fire until 3:15 p.m. and severely damaged the old and new front lines, which took much work to repair.

)[21] The fighting at the Bluff was one of nine sudden attacks for local gains made by the Germans and the British between the appointment of Sir Douglas Haig as commander in chief of the BEF and the beginning of the Battle of the Somme.

For political reasons, giving up ground around Ypres in Belgium was also unacceptable, only an advance could be contemplated to improve the positions of the BEF.

A substantial cadre of German pre-war trained officers NCOs and soldiers remained; the British wartime volunteers gained experience in minor tactics but success usually came from machine-guns and the accuracy and quantity of artillery support, not individual skill and bravery.

[26] The Germans dug long galleries beneath the Bluff and on 25 July the 1st Company, 24th Pioneers blew a mine under the ridge.

[30] The Germans re-took the Bluff during the Spring Offensive of 1918 and it changed hands for the last time on 28 September 1918, after an attack by the 14th (Light) Division.