In 1873 the British Captain John Moresby sailed HMS Basilisk into the cluster of islands off the southeastern tip of New Guinea and went ashore for a meal. He named the place Dinner Island on the spot, a casually colonial christening typical of that decade of Pacific mapping. The indigenous name - Samarai - survived Moresby's lunch, and eventually reclaimed the island entirely. Five years later the Reverend S. MacFarlane of the London Missionary Society planted a mission station on the hilltop. A British protectorate was declared over the southeastern quarter of New Guinea in 1884, and a government officer was posted. That same year a single trader arrived with sixty Papuan labourers and opened a beachfront store to sell to the steamers now pausing in the China Strait between Sydney and Hong Kong. The business made money. The traders brought more traders. The hotels followed. Within a decade Samarai had a jetty, a hospital, a rowing club, a cricket ground, and a cemetery filling quickly with men who had caught the wrong kind of fever.

Samarai's original problem was the mangrove swamp that covered most of its interior. It bred mosquitoes the way any tropical swamp breeds mosquitoes, which is to say in uncountable, lethal numbers, and malaria killed residents relentlessly through the 1880s and 1890s. In 1898 the swamp was filled in. The island, small enough that one could walk around it in twenty minutes, became properly habitable, and its commercial momentum accelerated. By the early 1900s it was, improbably, the commercial engine of the Territory. Port Moresby, the administrative capital on the mainland, handled the business of government. Samarai handled the business of business - the copra, the pearl shell, the labour recruiting, the shipping. When the Australian writer Jack McLaren worked there before the First World War, he described a boom-town crossroads where planters in from the Trobriands stood at the bar of the Cosmopolitan Hotel next to German traders, Chinese merchants, and schooner captains from every port between Singapore and Suva. For a few decades, this one-square-kilometre island looked at the century and thought it might be the future.

When the Japanese advance through the Pacific reached New Guinea in 1942, the British colonial authorities made a calculation about Samarai and came to a hard answer. If the town fell into Japanese hands it would give them a ready-made base at the eastern approaches to Milne Bay, with wharves, warehouses, a hospital and stores intact. So the British ordered Samarai destroyed. Australian demolition teams moved through the town systematically, burning and breaking, levelling the infrastructure that had taken sixty years to accumulate. The residents had already been evacuated. What was left when the troops finished looked like what it was - a small tropical island that had lost its twentieth century in a single week. The Battle of Milne Bay that followed in August and September 1942, fought thirty miles west, became the first Allied land defeat of Japanese forces in the war. Samarai was rebuilt after the war, slowly, modestly, and it continued as the provincial headquarters for Milne Bay. But the pulse had gone. In 1968 the provincial capital was moved to Alotau on the mainland, and Samarai stopped being anybody's capital.

The phrase Sorong to Samarai, sometimes shortened to S2S, travels a long way across a fractured political geography. Sorong sits at the western end of the island of New Guinea, in what is now Indonesia's Southwest Papua province. Samarai sits at the eastern end, in Papua New Guinea. Between them lies every Papuan community, every language, every highland valley and coastal village on the island. The phrase is used by Papuan independence activists on the Indonesian side to argue for Papuan unification, standing deliberately against the Indonesian national slogan "Sabang to Merauke," which sweeps from Sumatra to Papua. It is used in Papua New Guinea as an expression of Melanesian solidarity. The musician Airileke, Papua New Guinean-Australian and ARIA-nominated, released a single called "Sorong Samarai" in 2016. A small abandoned island in the China Strait lends its name, still, to a political geography that stretches two thousand kilometres and involves millions of people.

The 2014 census counted 460 people on Samarai. The number has been declining steadily. The island is split administratively into Samarai South and Samarai North wards, both in the Bwanabwana Rural Local Level Government Area, Samarai-Murua District. Two species of bat - the Lesser Papuan pipistrelle and Watts's pipistrelle - give the island its entry in mammalogy texts. In 2006 Prime Minister Michael Somare declared Samarai a National Historical Heritage Island and promised to restore its buildings and services as a tourist attraction. Some restoration has happened. The port was renovated in recent years. The old colonial buildings still stand in various states of decay, and photographs of Samarai in 1906 circulate online showing a busy commercial street that bears almost no resemblance to what a visitor finds now. The island remains reachable by small boat from Alotau, about four hours across open water. From the air it is a tight green teardrop against the pale blue of the China Strait - small, nearly abandoned, and holding history in a way that very few other places in the Pacific quite manage.