In the spring of 1918, the German Empire made a final, audacious attempt to break the stalemate on the Western Front. German troops had spent the winter learning a new style of trench warfare inspired by the successful tactics of the Russians under Alexei Brusilov two years before. The artillery barrages that preceded attacks became shorter and more precisely timed to preserve the advantage of surprise. Instead of advancing on enemy positions in mass waves, troops were instructed to cross the front in small groups and improvise once they reached enemy trenches. Initially, the offensive was a stunning success, punching a hole in the Allied line and allowing German troops to pour through it. But for the offensive to pay strategic dividends, the Germans needed to widen the hole in the enemy lines. Otherwise, the Allies could later repair the breach and cut the advancing enemy troops off from supplies and reinforcement. The key to the battle was French fortifications near the city of Reims, which is that awkward corner on the left-hand side of the German gains. If Reims had fallen, German troops might have been able to widen the breach in the French line and march down to Paris. But Reims didn’t fall, and so German troops became more vulnerable the deeper they marched into French territory. After repeated attempts to take Reims failed, the Germans were forced to abandon the territory they had taken to avoid being cut off.