In 4.40 on the morning of March 21, 1918, 6500 German guns and 2500 trench mortars opened up on the British lines on the Western Front in the most intensive artillery barrage of the war.
Five hours later, 32 German divisions, with 28 more in support, attacked on an 80km front, infiltrating British lines, bypassing strongpoints and thrusting deep into enemy territory.
The "Michael" offensive - the greatest German onslaught since 1914 and arguably the decisive battle of the war - had begun.
By nightfall on the 21st, the Germans had penetrated British lines to a depth of 13km, inflicted more than 38,000 casualties, including 21,000 prisoners of war, captured 500 guns, and taken nearly 260sq km of territory.
Two British armies - the Third and the Fifth - were falling back and over the next six days would retreat some 60km before the rapidly advancing Germans.
The strategic aim of the German high command was to drive a wedge between the British and French armies on the Western Front and then swing north and destroy the British army piecemeal or drive it back on the channel ports.
When the Germans struck on March 21, the New Zealand Division was in Flanders recovering from the disaster of Passchendaele five months before and a particularly grim winter in the Ypres Salient. Major-General Sir Andrew (Guy) Russell was ordered to rush his division southeast to the old Somme battlefield where the British army had already lost most of the territory won in the bloody fighting of 1916.
There, with three Australian divisions, they would attempt to plug an 8km gap between V and IV Corps of the Third Army, through which German storm troops were now rapidly moving to threaten the key railway junction at Amiens.
Getting there would involve a forced march of up to 50km in full battle order, which meant that they were without packs, blankets or greatcoats.
The New Zealanders arrived battalion by battalion on the Somme on the morning of March 26 and were thrown immediately into the gap in the line between the villages of Hamel and Puisieux-au-Mont.
By committing his battalions piecemeal to battle without artillery support, Russell was taking an unavoidable risk, but by hard fighting the New Zealanders first held and later drove back the German forces around the village of Auchonvillers.
By the morning of March 27 they had linked up with the Australians and the gateway to Amiens was closed.
The Germans counterattacked all that day in an attempt to break through, abandoning their infiltration tactics for full-frontal assaults on the New Zealand positions.
Well led by their NCOs and junior officers, the men fought back tenaciously and the line held.
Russell's message to his commanders was blunt: "Here we are and here we stay. We've wire in front, on our flanks and to our rear. No matter what happens, there's to be no retreating. The division stands firm."
Russell was well aware of what he was asking.
His outnumbered troops were fighting off repeated attacks for 36 hours without the support of their artillery, and they were short of food, shelter and warm clothes.
On the night of March 28, it began to rain continuously and the New Zealand trenches were soon knee-deep in mud and water.
On March 30 the division counterattacked and captured the high ground of La Signy Farm, which gave it clear visibility over the Ancre valley and over the German positions, along with 300 prisoners and 120 captured machine guns.
Though a small operation in tactical terms, it was the first successful offensive action taken by the British army on the Western Front since the start of the Michael offensive nine days earlier.
In the words of Australian war correspondent Charles Bean, "the news of it came in those dark days like a tonic to the whole of the British Army and to the Empire".
On April 5, 10 German divisions launched a fresh assault on the Third Army front in a last attempt to batter their way through to Amiens.
Again the New Zealanders faced heavy artillery bombardment and mass infantry attacks, and again they held on stubbornly, their machine guns inflicting heavy losses on the German troops.
A German regiment against which they fought would later acknowledge the "colossal toughness" with which the New Zealanders had held the line south of Hebuterne.
But by now the Germans had outrun their lines of supply and this, combined with the failure of their assaults on the Third Army front, brought the Michael offensive finally to a halt just 14km short of Amiens.
Among the 163,500 British and Dominion troops killed, wounded or taken prisoner in 16 days of battle were nearly 3000 soldiers of the New Zealand Division.
Jock Vennell is writing a biography of Sir Andrew Russell and would appreciate any information that would help him with the project. (04) 971-5249. jock@qualityhealth.org.nz
