The Belgian Army's pre-war rifle range at Polygon Wood needed somewhere safe for bullets to land. A long mound of piled earth, the butte, served as the backstop - the same simple structure shooters have used for centuries. When fighting reached this corner of Flanders in 1914, the butte was a feature on military maps, a piece of ground that meant something to artillery observers. By the autumn of 1917, when the Australian 5th Division attacked through Polygon Wood during the Battle of Polygon Wood, the surrounding pine plantation had been reduced to splinters and stumps. The butte itself, dense earth heaped many feet high, was one of the few features still recognisable from before the war. The Australians later built a memorial to their 5th Division on top of it - using, in a small mercy of irony, the labour of German prisoners of war.

After the Armistice, the Imperial War Graves Commission faced an arithmetic problem of horrifying scale: thousands of small wartime cemeteries and isolated graves across hundreds of square miles. Where possible, the dead were left in place and their resting grounds maintained. Where the small burial grounds had been destroyed, or had become impossible to access, men were brought together into larger sites. Buttes New British Cemetery, on flat ground in the north-eastern corner of Polygon Wood about eight kilometres east of Ieper, was one of those concentration cemeteries. Most of the 2,108 men buried here did not die where they now lie. They were gathered in from a sector that had seen heavy fighting through the wet winter of 1917 into 1918 - moved by working parties under canvas, identified where possible, given the names they could still be given.

More than half the burials are British soldiers. 564 are Australians of the First Australian Imperial Force - the men of the 5th Division and the units that followed them. 162 are New Zealanders. Five are Canadians. Thirty more are listed simply as of unknown nationality - men whose remains carried no badge, no scrap of uniform, nothing to say where they came from. The majority of all the burials are unknown by name. Each of those headstones bears the same words devised by Rudyard Kipling, who had lost his own son at Loos and who wrote the inscriptions used across the Commission's cemeteries: 'A Soldier of the Great War, Known Unto God.' The sentence does what it can. It says that someone is here. It admits that no one knows who.

The Flanders ground does not give up its dead all at once. Fields are still ploughed; drains are still dug. In 2006, a drainlayer working in the area uncovered the remains of five Australian soldiers. In October 2007 they were buried at Buttes New British Cemetery in a ceremony attended by Major-General Michael Jeffery, then Governor-General of Australia, and Helen Clark, then Prime Minister of New Zealand. Five graves added to the rows. Five families, somewhere, given a place to stand. Discoveries like this still happen - perhaps less often than they did, but not yet rarely. Across the Salient, the Commission and its forensic specialists work through bones turned up by farmers and construction crews, looking for shoulder titles, identity discs, a regimental button, anything that might allow a name to be cut into stone after a century underground.

The cemetery is quiet now in a way Polygon Wood has not always been. Pines have grown back, planted in regular rows by the Belgian forestry service after the war. The butte rises to the west, the Australian memorial pale against the sky on top of it. The New Zealand Memorial to the Missing - an obelisk designed by Charles Holden - stands on the cemetery's eastern boundary, listing the names of 378 New Zealanders with no known grave. The Stone of Remembrance and Cross of Sacrifice anchor the central walk. Visitors come in summer and in November, walking the rows, reading the inscriptions families chose, the ones that survived the war's grinding-down of language and still try to say something about a particular son or husband. The men under the grass are mostly nameless. The grass remembers them by being kept.