The first weeks of WW1 gave a deceptive impression that the war would be one of movement ..
The headlong infantry attacks and the futility of them soon became apparent to all sides , in the face of modern rifles , machine guns and artillery both sides were compelled to dig deep holes in the ground and concentrate upon breaking up attacks by their enemy . The armies remained in these holes for the next four years .
The beginning of trench warfare proper is usually given as September 1914 , when the German VII Reserve Corps turned around on the Chemin des Dames Ridge and blocked the advance of the British 1 Corps . Within a few weeks the stalemate spread down the whole battle line . This line ran from the North Sea to the Swiss frontier , a distance of 475 miles.
The German commander von Falkenhayn was the first to dig - in , deciding to hold onto the ground captured by his forces ,
The Germans occupied much of Belgium , and most of the industrially productive regions of northern France . It was thus a strategic necessity for the Allies to win back this lost ground . The Germans could afford to stand on the defensive and let the Allies exhaust themselves in attacking the strategic German positions To sum up , the trenches were defensive earthworks , deep emplacements protected by up to 50ft in depth of barbed wire to give protection for the defenders and formidable obstacles for the attacker