linguistic:paraphrasing, information:extraction, information:filtering
The great withdrawal and defending the Western Front

On the Western Front, the Third OHL deduced the German Army's huge salient between the valley of the Somme and Laon obviously was vulnerable to a pincer attack, which indeed the French were planning. The new Hindenburg line ran across its base. Subsequently, On 16 March, Hindenburg authorized Operation Alberich whereby German forces were ordered to move out all able-bodied inhabitants and portable possessions to this line. In the process, they destroyed every building, leveled all roads and bridges, cut down every tree, fouled every well, and burned every combustible. In 39 days the Germans withdrew from a 1000 mi (2,590 km) area, more ground than they had lost to all Allied offensives since 1914. The cautiously following Allies also had to cope with booby traps, some exploding a month later. The new German front called the Hindenburg line was 42 km (26 mi) shorter freeing-up 14 German divisions.

On 9 April, the British attacked at Arras and overtook two German lines while occupying part of a third as the Canadians swept the Germans completely off the Vimy Ridge. When the excitable Ludendorff became distraught over such developments, Hindenburg reportedly calmed his First Quartermaster-General by "pressing his hand" and assuring him, " We have lived through more critical times than today together. " Ultimately, the British tried to exploit their opening with a futile cavalry charge but did not press further. In the battle's aftermath, the Third OHL discovered one reason behind the British attack's success was that the Sixth Army commander, Ludwig von Falkenhausen, had failed to properly apply their instructions for a defense in depth by keeping reserve troops too far back from the front lines. As a result of this failure, Falkenhausen along with several staff officers were stripped of their command.