'That's VC up there,' said Cobra One. He pointed to a series of ridges that grew, off in the distance, into hills. 'You could say 80 per cent of the country is controlled by the VC, but that doesn't mean anything because they only have 10 per cent of the population.'

'I was up there,' said Dial. I kept forgetting that Dial had been a Marine. 'We were on patrol for about three weeks. Christ, we were cold! But now and then we'd luck out and get to a village. The people would see us coming and run away, and we'd use their huts – sleep in their beds. I remember a couple of times – it really killed me – we had to burn all their furniture to keep warm. We couldn't find any firewood.'

The mountains had begun to rise, acquiring the shape of amphitheatres with a prospect of the China Sea; eerie and bare and blue, their summits smothered in mist, they trailed smoke from slash-and-burn fires. We were on the narrow coastal strip, moving south on the patchy shoreline that still belonged to the Saigon government, between the mountains and the sea. The weather had changed, or perhaps we had finally been dragged free of the drizzle that was constant in Hue. Now it was sunny and warm: the Vietnamese climbed up to the roofs of the coaches and sat with their legs hanging past the eaves. We were close enough to the beach to hear the pounding surf, and ahead in the curving inlets that doubled up the train, fishing smacks and canoes rode the frothy breakers to the shore, where men in parasol hats spun circular webbed nets over the crayfish.

'God, this is such a beautiful country,' said Cobra Two. She was snapping pictures out the window, but no picture could duplicate the complexity of the beauty: over there, the sun lighted a bomb scar in the forest, and next to it smoke filled the bowl of a valley; a column of rain from one fugitive cloud slanted on another slope, and the blue gave way to black green, to rice green on the flat fields of shoots, which became, after a strip of sand, an immensity of blue ocean. The distances were enormous and the landscape was so large it had to be studied in parts, like a mural seen by a child.

'I had no idea,' I said. Of all the places the railway had taken me since London, this was the loveliest.

'No one knows it,' said Cobra Two. 'No one in the States has the slightest idea how beautiful it is. Look at that – God, look at that!'

We were at the fringes of a bay that was green and sparkling in bright sunlight. Beyond the leaping jade plates of the sea was an overhang of cliffs and the sight of a valley so large it contained sun, smoke, rain, and cloud – all at once – independent quantities of colour. I had been unprepared for this beauty; it surprised and humbled me in the same degree the emptiness had in rural India. Who has mentioned the simple fact that the heights of Vietnam are places of unimaginable grandeur? Though we can hardly blame a frightened draftee for not noticing this magnificence, we should have known all along that the French would not have colonized it, nor would the Americans have fought so long, if such ripeness did not invite the eye to take it.

'That's the Ashau Valley,' said Cobra One, who until then had been doing an amusing imitation of Walter Brennan. The ridges mounted into the mist; below them, in the smoke and sun, were deep black gorges marked by waterfalls. Cobra One was shaking his head: 'A lot of good men died there.'

Dazzled by the scenery, I walked through the train and saw a blind man feeling his way to the door -1 could hear his lungs working like a bellows; wrinkled old ladies with black teeth and black pyjamas clutched wicker bales of spring onions; and soldiers – one ashen-faced in a wheelchair, one on crutches, others with new bandages on their hands and heads, and all of them in the American uniforms that suggested travesty in its true sense. An official moved through the coaches checking the ID cards of civilian males, looking for draft evaders. This official got tangled in the piece of string held by a blind man and attached to the waist of a child leading him. There were many armed soldiers on the train, but none looked like escorts. The train was defended by concentrations of soldiers at those bridge emplacements, and this is perhaps why it is so easy to blow up the line with command-detonated mines. These mines are slipped under the rails at night; when the train goes over one of them, a hidden man – who might be a Viet Cong or a bomber hired by a trucker in Danang – explodes the charge.

Twice during that trip, at small station sidings, children were offered to me by old ladies; they were like the pale-skinned, light-haired children I had seen in Can Tho and Bien Hoa. But these were older, perhaps four or five, and it was strange to hear these American-looking children speaking Vietnamese. It was even stranger to see the small Vietnamese farmers in the vastness of a landscape whose beautiful trees and ravines and jade crags – these launched from cloud banks – hid their enemies. From the train I could turn my eyes to the mountains and almost forget the country's name, but the truth was closer and cruel: the Vietnamese had been damaged and then abandoned, almost as if, dressed in our clothes, they had been mistaken for us and shot at; as if, just when they had come to believe that we were identified with them, we had bolted. It was not that simple, but it was nearer to describing that sad history than the urgent opinions of anguished Americans who, stropping Occam's Razor, classified the war as a string of atrocities, a series of purely political errors, or a piece of interrupted heroism. The tragedy was that we had come, and, from the beginning, had not planned to stay: Danang was to be proof of that.

The train was under the gigantic Hai Van Pass ('The Pass of Clouds'), a natural division on the north side of Danang, like a Roman wall. If the Viet Cong got past it, the way would be clear to Danang, and already the Viet Cong were bivouacked on the far slopes, waiting. Like the other stretches between Hue and Danang, the most scenically dramatic mountains and valleys were – and are still – the most terrible battlefields. Beyond the Hai Van Pass we entered a long tunnel. By this time I had walked the length of the train and was standing on the front balcony of the diesel, under the bright headlights. Ahead, a large bat dislodged itself from the ceiling and flapped clumsily this way and that, winging against the walls, trying to keep ahead of the roaring engine. The bat swooped, grazing the track, then rose – more slowly now – as the end of the tunnel came into view, flying closer to the engine with every second. It was like a toy of wood and paper, its spring running down, and at last it was ten feet from my face, a brown panicky creature beating its bony wings. It tired, dropped a few feet, then in the light of the tunnel's exit – a light it could not see -its wings collapsed, it pitched forward, and quickly tumbled under the engine's wheels.

'The Street without Joy' was above us as we raced across a treeless promontory to the Nam Ho Bridge, five dark spans secured against underwater sappers by great rusting wreaths of barbed wire. These were the outer wastes of Danang, a grim district of supply bases that has been taken over by ARVN forces and squatters; shelters – huts and lean-tos – made exclusively with war materials, sandbags, plastic sheeting, corrugated iron stamped U.S. army, and food wrappers marked with the initials of charitable agencies. Danang was pushed next to the sea and all the land around it had been stripped of trees. If ever a place looked poisoned, it was Danang.

Raiding and looting were skills the war had required the Vietnamese to learn. We got out at Danang Station and after lunch drove with an American official to the south side of the city, where GIs had been housed in several large camps. Once there had been thousands of American soldiers; now there were none. But the barracks were filled to bursting with refugees; because there had been no maintenance, the camps were in a sorry condition and looked as if they had been shelled. Laundry flew from the flagpoles; windows were broken or boarded-up; there were cooking fires in the roads. The less lucky refugees had set up house in wheelless trucks and the sewage stink was terrible – the camps could be smelled two hundred yards away.