But the German commanders were no despicable antagonists. In Flanders the nature of the ground did not permit of the kind of defence which they had built on the Somme. Deep dug-outs and concrete trenches were impossible because of the waterlogged soil, and they were compelled to employ new tactics. Their solution was the "pill-box." This was a small concrete fort situated among the ruins of a farm or in some piece of shell-torn woodland, often raised only a yard or two above the ground-level, and bristling with machine-guns. The low entrance was at the rear of the pill-box, which held from eight to forty men. Such forts were easy to make, for the wooden or steel framework could be brought up on any dark night and filled with concrete. They were placed with great skill, and in the barbed-wire defences alleys were left so that an unwary advance would be trapped and exposed to enfilading fire. Their small size made them a difficult mark for heavy guns, and since they were protected by concrete at least 3 feet thick they were impregnable to ordinary field artillery.
The enemy's plan was to hold his first line—which was often a mere string of shell craters—with few men, who would fall back before an assault. He had his guns well behind, so that they would not be captured in the first rush, and would be available for a barrage if his opponents became entangled in the pill-box zone. Lastly, he had his reserves in the second line, ready for the counterstroke before the attack could secure its position. Such tactics were admirably suited to the exposed and contorted ground of the Salient. Any attack would be allowed to make some advance; but if the German plan worked well this advance would be short-lived, and would be dearly paid for. Instead of the cast-iron front of the rest of the battleground, the Flanders line would be highly elastic, but after pressure it would spring back into position with a deadly rebound.
The action began on 31st July, and resulted at first in a brilliant success. But with the attack the weather broke, and so made impossible the series of blows which we had planned. For a fortnight we were compelled to hold our hand; till the countryside grew drier, advance was a stark impossibility.
The second stage began on 16th August, and everywhere fell short of its main objective. The ground was sloppy and tangled; broken woods impeded our advance; and the whole front was dotted with pill-boxes, against which we had not yet discovered the proper weapon. The result was a serious British check. Fine brigades had been hurled in succession against a solid wall, and had been sorely battered. They felt that they were being sacrificed blindly; that every fight was a soldier's and not a general's fight; and that such sledge-hammer tactics could never solve the problem. For a moment there was a real wave of disheartenment in the British ranks.
Sir Douglas Haig took time to reorganize his front and prepare a new plan. Sir Herbert Plumer was brought farther north, and patiently grappled with the "pill-box" problem. He had them carefully reconnoitred, and by directing gun fire on each side enabled his troops to get round their undefended rear. Early in September the weather improved, the mud of the Salient hardened, and the streams became streams again, and not lagoons.
On 20th September the third attack was launched, and everywhere succeeded. It broke through the German defence in the Salient, and won the southern pivot, on which the security of the main Passchendaele Ridge depended. Few struggles in the campaign were more desperate or carried out on a more gruesome battlefield. The maze of quagmires, splintered woods, ruined husks of pill-boxes, water-filled shell-holes and foul creeks, which made up the land on both sides of the Menin road, was a sight which to most men must seem in the retrospect a fevered nightmare. The elements had blended with each other to make of it a limbo outside mortal experience and almost beyond human imagining.
But successful though the advance was, not even the first stage of the British plan had been reached. During the rest of September and October, however, attack followed attack, though the main objective was now out of the question. It was necessary to continue the battle for the sake of our Allies, who at the moment were hard pressed in other areas; and, in any case, it was desirable to complete the capture of the Passchendaele Ridge so as to give us a good winter position.
The last stages of this Third Battle of Ypres were probably the muddiest combats ever known in the history of war. It rained incessantly, sometimes quieting to a drizzle or a Scots mist, but relapsing into a downpour on any day fixed for our attack. The British movements became a barometer. Whenever it was more than usually tempestuous it was safe to assume that some hour of advance was near. The few rare hours of watery sunshine had no effect upon the irreclaimable bog. "You might as well," wrote one observer, "try to empty a bath by holding lighted matches over it."
On the 30th October our line was sufficiently far advanced for the attack on Passchendaele itself. On that day the Canadians, assisted by the Royal Naval Division and London Territorials, carried much of the Ridge, and won their way into the outskirts of Passchendaele village. Some days of dry weather followed, and early in the morning of 6th November the Canadians swept forward again and carried the whole main ridge of West Flanders. By this achievement the Salient, where for three years we had been at the mercy of the German guns, was no longer dominated by the enemy position.
The Third Battle of Ypres was strategically a British failure; we did not come within measurable distance of our main purpose. But that was due to no fault of generalship or fighting qualities, but to the malevolence of the weather in a country where the weather was all in all. We reckoned upon a normal August, and we did not get it. The sea of mud which lay around the Salient was the true defence of the enemy.