On November 20, 1917, the British Army began a combined arms attack, including infantry, artillery, tanks, and airplanes, against German forces defending the critical supply point for the Hindenberg Line at Cambrai.

The British were able to penetrate several kilometers into German lines during the first day, losing only about 4000 soldiers.  However, losses of British tanks were heavy due to large numbers of mechanical breakdowns and German resistance, and only half of their tanks were available for use on the second day of the battle.  British advances after this were costly and slow.

On November 30, the German counter-offensive at Cambrai began, with the Germans using new infiltration tactics against the British.  In the end, the Germans were able to push the British off of most of their initial gains, while taking a small bite out of pre-battle British positions.   Casualties were also relatively equal, with each side losing approximately 50,000 men during about two weeks of fighting.

Cambrai was a laboratory for new tactics and equipment on both sides of the lines.  The British demonstrated growing skill at coordinating artillery with infantry attacks, while their use of massed tanks to overcome German obstacles further demonstrated the usefulness of this new weapon.  German techniques to infiltrate enemy lines with groups of specially trained soldiers, as well as their use of anti-tank tactics and weapons, were used to great effect during the last year of the war.