In spring 1918, Germany realized that time was running out. It prepared for the decisive strike with new armies and new tactics, hoping to win the war on the Western front before millions of American and British Empire soldiers appeared in battle. General Erich Ludendorff and Field Marshal Paul von Hindenburg had full control of the army, they had a large supply of reinforcements moved from the Eastern front, and they trained storm troopers with new tactics to race through the trenches and attack the enemy's command and communications centers. The new tactics would indeed restore mobility to the Western front, but the German army was too optimistic.