On October 17, 1927, HMAS Adelaide slipped into Sinalanggu Harbour on the island of Malaita in the British Solomon Islands Protectorate. Aboard the light cruiser was an extended crew of 470 sailors with extra arms and ammunition, primed to quell a “native uprising”. The vessel had been dispatched by the Australian government at the behest of the British.

Several weeks earlier, a party of 15 local policemen had accompanied Australian-born District Officer William Bell and his assistant Kenneth Lillies to a village on the harbour shore to collect a tax. The “head tax” had been levied on every able-bodied Solomon Islands man to force them into labour – because the British needed workers on their plantations – but the Kwaio people of central Malaita, proud and independent, were determined to resist. Some had been blackbirded and forced to tend Queensland’s sugarcane fields, and were fighting against re-enslavement. The tax collectors were expecting trouble and came armed with the latest rifles. But the skilful Kwaio, despite being equipped largely with Stone Age weapons, attacked the party and managed to kill almost all of them, including Bell, while losing just one of their own.

As the Adelaide anchored in the calm harbour the Kwaio leader, Basiana, who had planned and led the attack, was watching from a ridge 900 metres above. The sailors had also been joined by a ragtag civilian militia from the nearby British administrative capital of Tulagi, eager to join a suppression of the natives. Their lacklustre contribution to the arduous expeditions up the mountainside, in search of Basiana’s stronghold, earned them the sobriquet “the breathless army” in the history books. But even the professionals were thwarted as the Kwaio melted into the jungle, and the Adelaide returned to Australia having failed to find their man. When they heard what had transpired, the British, infuriated at the impasse, decided to arm some north Malaitans who were then in conflict with the Kwaio, giving them carte blanche to kill. Not only did the north Malaitans murder dozens of men, women and children, they also desecrated the Kwaio’s ancestral shrines.

Faced with a genocide, Basiana and his most loyal supporters made the ultimate sacrifice, walking to the coast and giving themselves up to be publicly hanged. Basiana’s body was never returned to his people: there was no closure for the Kwaio. Instead they became enmeshed in enmity with the north Malaitans and Australians, and a series of payback killings rolled on for 91 years. One of the last Australian victims, a 60-year-old missionary, was beheaded in 2003.

I first visited Kwaio country in 1987, at the invitation of Wailamo. His father, Folofou, had been a youth in 1927 and recalled vividly the events of that year. High in the mountains, the Kwaio were cut off from the world. Refusing Christianisation, and indeed most outside influences, they continued to live largely as their ancestors had done for thousands of years. The visit left a deep impression on me.

In 2015, when the chance to fund a community conservation project in the Solomon Islands presented itself, I immediately thought of the Kwaio. Through public health researcher David MacLaren, I contacted Chief Esau Kekeubata, explaining that a European charitable foundation was willing to support his people to protect forests and manage their biodiversity by eliminating feral cats and monitoring endangered species. The timing was perfect: loggers were just moving into the last of the Kwaio forest. Despite the project’s great success, in February 2018 Esau explained that there was a problem: our researchers were not safe. A traditional reconciliation ceremony was needed to deal with the events triggered in 1927. Seeking acceptance of the ceremony by the Kwaio, Chief Esau and his son Tommy travelled for weeks between the scattered communities, eventually convincing 90 per cent of the Kwaio to agree to it.

A reconciliation demands participation from both sides, and Esau had invited the Australian and British high commissioners, as well as myself (in my official capacity as 2007 Australian of the Year) to accept compensation for the European deaths. But when I arrived at the foot of the Kwaio mountains last July to begin my ascent to Basiana’s realm, I discovered that I was the only invitee who had accepted.

Chief Esau is waiting for me in a typical “banana boat” – an open vessel with an outboard motor – at the ramshackle, mangrove-ridden shanty port of Atori. The bodies of William Bell and Kenneth Lillies lie buried a kilometre or so offshore, on the small island of Ngongosila. The island is not Kwaio country, and Esau has to request permission to visit the sombre granite headstones. We pay our respects and, in the failing light, set out again south-eastwards, into the teeth of a gale, a great, rolling swell tossing our boat like a dry leaf. As we approach a reef, the sound and spectacle of the swell bursting on jagged coral is awful. It is pitch dark by the time we reach a tiny islet called Gala, only a few metres off the mainland across a mangrove channel, where in a bush-materials guesthouse I meet David MacLaren and Esau’s son Tommy. Biologist Tyrone Lavery, cinematographer Ben Speare and David’s son Hamish make up the rest of the party.

As we eat together – boiled sweet potato, roast taro and greens – Esau seems nervous. There are a few who can’t put their thirst for revenge aside, he says. Later that evening Esau tells me about himself. He was expelled from school in Grade Two and became a bank robber in Honiara. He had also stolen 87 pigs. “When you reach 100, you have to kill a man,” he says in pidgin English, in reference to the rules of the Ramo (a Kwaio strongman). Unwilling to kill, he decided to change his ways and is now an outstanding leader. But such was his reputation that in 2002 he was invited to hunt and kill Harold Keke, a notorious warlord on the island of Guadalcanal who was implicated in the murder of 50 people, including a cabinet minister and an Anglican priest. The prime minister had put up a reward – a bounty in the eyes of the Kwaio. Esau declined the mission, but the 10 Kwaio who accepted were all killed by Keke’s henchmen.

I haven’t slept well. We take the banana boat in heavy rain to a landing place where we are met by a “security” contingent: sullen young men armed with bows and arrows, bush knives, axes and clubs. The rain is unrelenting, the river so furious I begin to wonder whether the ancestors want this reconciliation. We start walking and by midday I’m exhausted, but the track just keeps rising. After feeling our way across a submerged log bridge it’s just up, up and up, through mud covering irregular limestone. Steep. Constant slips and falls.

The afternoon is well advanced when Esau announces that the reconciliation ceremony cannot happen today: we must spend the night in the village under guard, and without ritual protection.

Just before dark we emerge out of the forest onto a ridge, where we ditch our sodden clothes and don traditional male Kwaio attire: a cane belt and leaf pubic cover. We walk into the village preceded by young men playing panpipes.

Next morning, in pouring rain, a party of senior men escorts us to an ancestral shrine deep in the forest. There we will hold a sacred ceremony that cannot be filmed or recorded – this is the realm of the ancestors, an eternal and immediate reality for the Kwaio that is perhaps impossible for secular Westerners to comprehend. We enter a surreal region of abrupt sinkholes, limestone boulders and gnarled, moss-covered trees. I am led by Kwaio elder Waneagea. As we approach a cave entrance he wails, and tears fill his eyes. It is Basiana’s hiding place, never before revealed to outsiders. Emotions are breaking out everywhere on the usually stoic Kwaio faces.

Several hundred metres upslope is a sinkhole where the bodies of murder victims and the bones of stolen pigs are disposed of. The horrible black void yawns just off the track. A few metres on I see three men standing in the pouring rain. It is ritual leader Diifaka with his brother and a son. The others fall behind me, leaving a long gap.

Diifaka is a shortish, muscular man with a square face and the most startling eyes I’ve ever seen. He is wearing a necklace strung with human teeth, and his body is quivering with nervous tension. For six months he hasn’t slept with his wife, eaten food cooked by a woman or entered a house: he is tabu. He motions me to stand a few feet from him. Everyone else assembles a good distance behind me. Diifaka’s brother is holding a black piglet, barely a week old. It is lying in his hand, atop two heart-shaped leaves. The creature is silent but shivering violently in the cold. The brother hands the piglet to me and I clasp it to my chest. My heartbeat and warmth seem to calm it almost instantly.

After a few moments Diifaka motions for the piglet. As I pass it over he lets out a deep wah!, and recites words I don’t understand, except for “Australia”, “England” and “Kwaio”. He hands the pig to his son, who touches it on the head with a sop of leaves. The brother then brushes it with a whisk before handing it back to me. This is done 90 times, once for each victim of the conflict, with each name inserted into the chanted formula. As Diifaka recites one name, his face contorts with emotion and he bursts into tears. I hear sobs behind me as other names are called out. It dawns on me that the moment an ancestor’s name is called, descendants are grieving as if the atrocities were committed just yesterday. The momentous occasion of the reconciliation is hitting home. After nearly a century we stand together to resolve a situation – according to Kwaio custom – that many thought was impossible.

After two hours standing in the rain, Diifaka takes the sop of leaves and brushes the bodies of everyone at the ceremony. He then takes a bush knife and divides a betel nut, giving me half. We both chew our portions. We are two halves of a whole – our tribes have had a violent history – but we are now chewing one betel nut as friends. The ancestral spirits now recognise us. Kwaio and Australian can continue as friends, as partners.

I follow Waneagea downslope. A rough sapling I’m holding to steady myself rips into the palm of my hand, leaving a diagonal gash. Waneagea abruptly turns upslope and onto another path. Behind me, Diifaka tosses the living piglet into the great sinkhole. I hear nothing, but visions of the tiny thing haunt me for days.

Morning brings mud and rain that never seems to end, but at midday we get a brief break and I see Waneagea and a second man standing before our hut, holding a long string of shell money on a stick. David MacLaren, Tyrone Lavery and I line up opposite them, and each of us is handed a piglet. The spirits of the Kwaio warriors hanged in 1927 need to be directly acknowledged: this exchange will conciliate them. A senior man named Laete’esafi, naked except for his cane belt, stands opposite me. As instructed, I say to him: “I give this pig for the ‘Ai’eda clan, and Basiana.” After days in his spiritual presence, I find it hard to say the name. David gives his pig for the Furi’ilia clan, Tyrone for the Ngudu YY clan.

Waneagea steps forward with the shell money. “I give you this for Mr Bell,” he says in Kwaio. Another senior man, Agumae, gives symbolic recompense to David “for Mr Lillies”. As he speaks, a cold, hard rain pelts down, and we run for shelter. We return to a hut where speeches are made, the last by a man who swings a club as he orates. All eyes are riveted on him, and as he finishes there’s a huge release of energy: a young man plays the pipes while men, women and children clap, dance and make celebratory speeches.

The following morning we head back to the coast. After a few hours we come to a clearing, where an old man sits, waiting for us. He explains that he never married, has no children, and will die soon. “No matter,” he says, as he gives David and me the most valuable of his shells. Then something incredible happens: a Sanford’s sea eagle, a rare bird I’ve seldom seen, soars overhead, circles us, then flies in the direction we are about to take. The bird is the totem of Malaita: every eye is on it as it vanishes into the haze.

A day later, over breakfast in the provincial capital of Auki, David tells me that our contingent of “security guards” was made up of the worst criminals in Kwaio. Their leader was the man who had beheaded the Australian missionary in 2003. Back then, Basiana had come to him in a dream, confirming that hostility between Australia and Kwaio remained. The reconciliation ceremony changed this in an instant. The man was also the one who gave that final speech, banging his club into his hand: “The time of blood is over.”

The ceremony was a catalyst. Kwaio leaders now actively discuss reconciliation with leaders across Malaita, including the north Malaitans. Even tribes within the Kwaio harbouring old enmities are now reconciling. Could this be a model to address historical enmities and right historical wrongs, both within Solomon Islands and beyond?