It’s not clear where the story of Arnhem Land’s Djalu Gurruwiwi begins or ends. It just meanders infinitely, back and forth, across the land and into the sea along the songlines that tell it.

Nobody is certain when Djalu – a spiritual keeper and master craftsman of the yirdaki (didgeridoo) as well as one of its most globally respected players – was born.

Ask Djalu where he came into the world and he’ll nominate the Methodist mission at Milingimbi Island in the Arafura Sea off the coast of Arnhem Land. In the next breath he’ll name Wirriku Island. It’s hard to find Wirriku on a modern map. But it’s the same as Jirgarri, a small island at the base of the Wessel group.

The spirits of Djalu’s Yolngu people are eternal. They exist in freshwater springs until human conception, and Djalu was conceived at Jirgarri before leaving his mother’s womb at Milingimbi about 1930. It took me a week to nail this single aspect of his life – not bad, given that others who’ve known him far longer still can’t reconcile so much about Djalu with what we outsiders regard as the truth. But then Djalu is not only a virtuoso of the yirdaki; he is also an artist, a tribal lawman, reputed enforcer, a healer, and perhaps the closest thing Australia has to a guru.

Little is said about Djalu’s birth mother. But his father, Monyu, was a fierce tribal warrior whose victims still, apparently, haunt Djalu and his family.

Djalu recalls holding Monyu’s hand and looking up as the Japanese bombers delivered their payloads. There are other stories too – apocryphal, perhaps, but who can really say? – of Monyu beheading rivals, fighting the Japanese with his little boy by his side and of the boy, Djalu, negotiating alone in a canoe the shark- and crocodile-ridden waters between islands.

These incidents are all possible reference points for non-Indigenous people like me – or balanda, as the Yolgnu call us – who are compelled to map Djalu’s corporeal existence as we do our own. But for the Yolngu people they mark just a few relatively recent notes (somewhere between the arrival of the Sulawesi traders five or six hundred years ago and the Japanese bombers) in the songlines that reach back 40,000-plus years and to which Djalu’s yirdaki gives voice.

Ask Djalu or his family when something relatively recent happened and you’re likely to be told: “Oh, after the Macassans and before the Japanese.”

I am in Arnhem Land for a small, finite story inside all of this: the five-year quest of a London-based film-maker, Ben Strunin, to make a movie, Baywara (Yolngu for lightning power), about Djalu. Strunin has been resolutely shooting and directing his film since first meeting Djalu at Heathrow airport at the beginning of the Yolngu man’s month-long European yirdaki tour five years ago.

Now, with the movie close to completion, Strunin has enlisted Nick Cave as the narrator. Another Australian musician, Wally De Backer (more famous as Gotye), the acclaimed Australian visual artist David Booth (Ghost Patrol) and one of the world’s most renowned photographers of popular musicians, Denmark’s Søren (Søren Solkær), have made the pilgrimage to Arnhem Land where, if Strunin’s narrative mud map transpires, Djalu will become their creative muse for a week or so.

A boat voyage into the temperamental Arafura Sea to camp at Raragala (an improbably beautiful, unspoilt, humanly uninhabited island in the Wessels where Djalu lived as a young man) with the subject and some of his family will be among the final takes in what is effectively Strunin’s quest to decode the Djalu enigma, and Guardian Australia is along for the ride.

The wind, which had been prohibitively strong for such a journey the week before, has dropped. The sea has correspondingly calmed. And so we’re about to sail 60 treacherous nautical miles out from the Gove peninsula to an island renowned for its snakes, with a frail man believed to be in his mid-80s, his elderly sister, his wife, her two dogs, and with five children – including Djalu’s son Vernon, grandson Kevin and three nieces.

What could go wrong?

When you’re carefully calibrating time and tide, potentially lethal currents and winds, a narrow and broiling channel between islands – not to mention a cranky rainbow serpent lurking in the waters about Raragala and a giant dog that guards against strange boats from a promontory we must pass – there are numerous possibilities.

And that’s before you even contemplate the gorillas.

A true holy man, a guru

It is the day before we are to set sail for Raragala aboard the Hama Pearl 11, a reassuringly solid 18-metre aluminium former pearling vessel, and Strunin is busy buying last minute supplies (cigarettes for the women, sugar products for his diabetes, seasickness tablets) and dealing with the seemingly indeterminate like who, precisely, will be travelling.

He has been planning this sea trip for the best part of a year. Strunin’s even temper and c’est la vie approach are rich commodities in a place like Wallaby Beach, the settlement outside the bauxite mining town of Nhulunbuy where Djalu, his family and an endless stream of visitors live. Here life just unfolds as it does. Which means rarely by the clock. Hurrying anyone can be counterproductive. Life’s rhythms are set by the yirdaki, the wind, the sea, the need to find food and money, which comes and goes like the constant parade of visitors, many from overseas, who respond to the allure of Djalu’s yirdaki like worshippers to the church bell.

Anyone who comes peacefully is welcomed; the Yolngu have little innate capacity for social exclusion. Djalu, as a revered elder – a spiritual keeper of the yirdaki and a healer – is correspondingly exceedingly generous. Which has a way of stretching already scare resources.

There is space for everyone here, Yolngu, balanda or other, and room, too, always for the beloved dogs, the music, the yirdaki-making and the painting that accompany it (both Djalu and his wife, Dhopiya, are acclaimed artists whose works – including yirdakis and occasional bark paintings – sell at the nearby Yirrkala art centre, Buku-Larrnggay Mulka).

Some of Djalu’s old acquaintances insist he is less famous and has far fewer financial rewards than he should. They say people come from everywhere and attach themselves to Djalu and his family.

One who has known and observed Djalu for many years says: “They either contribute to the upkeep or not. And everyone gets welcomed by him and then stays absolutely as long as they like. The actual instrument, the yirdaki, lures all sorts of people to Wallaby Beach: doctors from Germany, rich hippy kids from Florida in designer rags, Rastafarians from Belgium, students from Japan. There has never been any suggestion that these people would be turned away ... Australia doesn’t have Gurus in the same way as India. But Djalu is perhaps the closest thing we have to ... a true holy man. I’m talking about somebody who embodies a Christ-like, Buddha-like kindness and generosity – cultural, physical, spiritual.”

An expansive mat is spread under the trees in Djalu’s front yard and, while eleventh-hour preparations for the voyage are made, Djalu and his family invite the visiting artists – Booth, Søren and De Backer – to take part in their art.

The previous day the trio had ventured deep into the bush with Djalu, Dhopiya and their son Larry for “yirdaki hunting” – seeking out appropriately hollow trees to fell and shape into instruments. Now Booth sits on the mat with Dhopiya and holds the hollowed-out, pared-down trunk while Dhopiya paints the soon-to-be instrument.

But first Dhopiya makes a new brush, its bristles cut from the firm but supple tail fur of one of her two companion dogs – a scraggy, long-haired, blond terrier that answers to Tiger. Another lapdog, Skipper, a russet-coloured bitzer with the head and temperament of a fox and the brush tail of a corgi, follows insistently in Dhopiya’s shadow. (There are other house dogs – big brutes: mastiffs cross-bred with what look like dobermans or danes – that patrol, territorially, the edges of Djalu and Dhopiya’s house.)

She paints the yirdaki with wallabies (denoting young people) and potatoes (old) and then segments it with thin, black bands. Booth sketches, asks her why she uses three black bands in some places, two in others.

“Sometimes,” she explains, “it only needs two.”

For former Melbourne street artist Ghost Patrol the experience with Dhopiya and Djalu is about “listening as a path to understanding”. He bonds quickly, tightly, with Dhopiya, over the dogs and the art.

“I know that my experience will have a large impact on my artwork – I’m not in a hurry to produce a reaction,” he says. “I’ve put aside a large chunk of time to meditate and try and download my mind into some drawings and paintings.”

Similarly De Backer is in no rush to produce music that incorporates Djalu’s sounds or those of either of his sons, Larry and Vernon, both yirdaki players (his young grandson Kevin is also adept).

While Booth and Dhopiya paint, De Backer goes into the studio at Yolngu Radio in Nhulunbuy to meet Larry and listen to his songs. It’s gospel music – odes to Jesus and dead relatives, played on the electric piano and sung by Larry in Yolngu.

With a decidedly non-rock’n’roll modesty that defines his time with Djalu and his family and greatly endears him to them, De Backer asks: “Is there something you could please teach me – a song that I could sing with you?”

Larry chooses Balay Balay, a song created by his father about the life and recent death of Djalu’s brother. Larry’s voice – rich, syrupy, high – is redolent of Geoffrey Gurrumul Yunupingu’s. This surprises nobody who knows Larry; his mother, Dhopiya, is from the Yunupingu clan of Arnhem Land artists and musicians (Djalu’s clan is the Galpu).

De Backer quickly beats in on the drum kit, lends his equally evocative, unmistakable voice to Balay Balay. Larry can’t write music or words. It’s all in his head. De Backer listens intently, mimics. And soon there’s sweet harmony.

Larry explains: “This song is based on a songline. My old man Djalu gave this song to me when his brother died. It’s the songline that’s my father’s brother’s ... He followed the land and he walked all along that songline and just then, in the end, I was singing about the water he crossed and then he came back and he followed his land again. Then he went out to Elcho [Island], across the water again, and that is the end of the song.

“The very last line in Yolngu is, ‘And he follow his father into the sea.’ ”

Larry and De Backer are both beaming as they leave the studio.

In the late afternoon, having helped pack the Hama Pearl 11 at nearby Ski Beach, Melbourne-born Strunin explains how he first learnt about Djalu from a friend in London who was organising the Yolngu man’s tour of Britain and continental Europe in 2009. The friend – who described Djalu as a “spiritual guru” about whom he’d “been having dreams” – suggested Strunin make a movie about the old man’s life.

Strunin met Djalu at Heathrow. They took a stretch limousine into central London. During the ride Djalu entrusted Strunin to make the movie. Strunin began by filming the month-long tour, which involved five-star hotels and sell-out houses in London, Germany, the Netherlands, France, Belgium and Italy. They shared hotel rooms and stories. Eventually Djalu and his family “adopted” Strunin.

“I think he wanted a film made about him being overseas and about him being treated with great reverence and like a rock star and like a guru by all these adoring fans in Europe, not for himself but that so that we could show the footage to the kids back at home ... So here we were [on tour] hanging out, exchanging stories and songs and jokes,” says Strunin. “And Djalu just seemed to be an incredible, generous person ... when it came to sharing his culture.

“What I started to understand quite quickly is that it’s not easy to understand Djalu when he tries to talk English and not all of these stories make sense instantly. You have to listen really hard. And he taught me to listen ... But I also saw the way he developed techniques to connect with balanda, to connect these two worlds in such a seamless way.”

Strunin says that even Djalu refers to himself as “the mystery man” because there is so much speculation about his past including that he, like his father, was a tribal warrior and enforcer.

During my few days around Djalu many of those who know him well stated – without ever offering proof – that he had been, as a younger man, a violent enforcer of tribal law. Certainly there are suggestions that his belief in the inviolability of tribal law has clashed, at times, with the orthodoxies of balanda civic culture.

Adding to the Djalu mystique is the embrace by him and Dhopiya’s clans (like so many Indigenous Australians who were touched by mission life) of Christianity. Djalu frequently officiates, with his yirdaki, at Christian occasions; his wife, sister Dhanggal Gurruwiwi, sons, daughters and grandchildren often refer to scripture, God and Jesus.

Many before Strunin have tried and failed to demystify Djalu. That’s partly because it’s hard to understand Djalu in either Yolngu or English owing to a speech impairment caused (again the mystery) by illness, an injury resulting from a tribal dispute – or perhaps even, some suggest, an enemy’s spell.

Strunin’s film will be subtitled and his translations are based on the work of Dhanggal, a teacher and interpreter who appeared on the ABC’s Q&A program from the Garma Festival in Arnhem Land. In an interview with Strunin late last month Djalu explained how he – metaphorically or literally; again, who can tell? – had an epiphany.

Strunin recounts how Djalu explained “I was a bad man” but “I fell off a cliff” and then “was captured by the hand of God” and that “expelled the bad man”.

The truth about the past, says Strunin, is relevant only to a point, especially considering Djalu’s life today as a Christian facilitator, a community leader, a bridge between Yolngu and balanda, a gentle healer and a keeper of the yirdaki.

“It’s a sacred instrument. It’s a powerful instrument that can be a healing instrument – it can share their knowledge, it can tell stories, it carries encyclopedias’ worth of information about the culture which, as part of a holistic system – including the songlines and the clapsticks – is central to an oral tradition, so nothing is written down,” Strunin says.

In a place where stories are incarnate in landscape, it is not surprising that such an old man is the subject of so many. Or, perhaps, that others – which may or may not be based on verifiable incidents – tend to perpetuate.

Like that one about the gorilla, which apparently survived a shipwreck – some time between the European occupation and now – and made it to shore on Raragala. There are multiple variations of the story. By some accounts the gorilla, touched by the magical sands on one part of the island, mutated into a giant. By others, it multiplied. Regardless, some in Arnhem Land know that a gorilla – or gorillas – live on the island. And that is reason enough to be wary of the place.

We return to Wallaby Beach at sunset after packing the boat in preparation for a 3am departure. Strunin disappears inside the house. His producer, Ben Pederick, says Djalu, it seems, may be having second thoughts about the voyage.

His reluctance is not because he is afraid of anything – he’s just tired, wary of travelling and fearful that he won’t be able to meet his commitments to his community if he leaves.

But Strunin manages to easily reassure Djalu. And so Djalu, Dhopiya and her two dogs, Dhanggal, the children, the nieces, the film-maker, the balanda artists and I all sail into the black Arafura at 4am, just as the first luminous hints of dawn threaten to crack the horizon.

If you know the song, you can find your way

Many Australians have tried to understand and explain the songlines.

At the most basic conceptual level, perhaps think of the songlines as the oral archives of Indigenous history that chart the very creation of the land and sea by the Dreaming totems (animals), and the various marks – trees, waterholes, rocky outcrops and creatures – along them. The songlines also hold the stories of the people and the eternal spirits who inhabit them. Because melodic variance is used to describe the land, the songlines – which also manifest in artworks, dance, the yirdaki and clapsticks – transcend language. The songlines or tracks transcend the language groups. If you know the song, you can navigate.

If you know the song, you can find your way from one end of the track to the other, even though the songline may pass through lands inhabited by many different people who speak a variety of languages.

An Englishman, Bruce Chatwin, presented one of the most detailed non-Indigenous accounts in his remarkable 1987 book The Songlines, writing that “... the melodic contour of the song describes the land over which the song passes ... certain phrases, certain combinations of musical notes, are thought to describe the actions of the ancestors’ feet. An expert song man … would count how many times he has crossed a river or scaled a ridge – and be able to calculate where, and how far along, the songline he was ... A musical phrase is a map reference. Music is a memory bank for finding one’s way about the world.”

On board the boat Djalu and his family sleep in the bunkroom while the rest of us stretch out on deck until the tequila sunrise fills our starboard skyline. The sea is blindingly glassy as we pass Cape Wilberforce and head towards the English Company Islands and on to Raragala. To reach the north-western side of island the captain, Kim Wilkinson, must negotiate the “hole in the wall” – a narrow passage between Raragala and neighbouring Galuwuri Island that, according to one of the songlines, appeared to put an end to a long war between neighbouring clans.

As we pass Cape Wilberforce Dhopiya points out the dog (a towering piece of bright red rock embedded in the cliff) that guards from strangers the waters we travel through.

“The dog is watching out here – it is part of one of our clan songs,” she says. “You see how smooth it is on the water today? Well that is because we are guiding you through. If you don’t ask our permission to come through this water here, because this is our country, then the sea is very rough.”

The wind picks up with the morning and as we approach the hole in the wall – which some of the passengers seem anxious about – the sea begins to chop up a little.

And here I ask Vernon Gurruwiwi about the gorillas.

“Who told you that?” he demands.

“Many people refer to stories about the gorillas on the island,” I say.

“No! There’re no gorillas. There’s just the rainbow serpent. That’s the totem of me and my dad. You see that point back at the very beginning of the channel there? Well, there’s a big cave up there and in there he lives, the giant rainbow serpent.

“He’s bigger than this boat, I’m telling you. If you don’t get permission before you go through here from the rainbow serpent and you go too fast he’ll come up from under the boat and tip you up. We got permission because he is our totem. Now that is the truth.”

Djalu sits on the forward deck as we round the coast of Raragala – long, low, flat, brown and crowned with green shrubs and trees.

He says he doesn’t know why the Hama Pearl 11 is taking so long to get us there; as a young man he canoed from Yirkkala on the Gove peninsula to Raragala and Elcho, where he found his wife, in just an hour or two. Then he talks about the Japanese airmen who bombed him during the war, and about how he helped the Japanese pearlers who came to Raragala after the war and how, more recently, he has taken some tourists from Japan yirdaki hunting.

I think of my uncle, who fought the Japanese in the Pacific, and spent a long lifetime thereafter hating them.

Djalu says he doesn’t know why the boat needs all of this navigational equipment, sonar and satellite instrumentation.

“You just have to follow the tracks, the songs, across the sea. You just have to remember them and you find your way. The tracks are in here,” he says, barely audibly, in English, pointing to his head. Then Djalu laughs. He keeps talking about his past as a younger man on Raragala. I want to ask him about those stories in his past – of dispensing and enforcing tribal law and so on. But the wind picks up and smothers his flimsy speaking voice. And I’m left, like everyone else, wondering.

We anchor. Djalu and his family and the artists are first ashore a beach that is equal parts sand and pinkish midden, thanks to centuries of shellfish cracked and eaten here.

Within half an hour Vernon has speared a shark and three other fish in shallows that teem with life, including clams that the women gather. A fire is lit, lunch cooked and the black snakes, which Skipper insists on chasing, assiduously avoided.

That afternoon the family and the artists explore another part of the island where they harvest dozens of cricket-ball-sized mussels, wild honey and more fish.

Just before dusk, as the aluminium dinghy heads back to the mother boat, Djalu notices a man holding a spear standing on the shore, looking back intently at him. Vernon sees him too.

Later Djalu explains: “Last night we seen the old person. He was standing there with the spear. He was there from my father. My father kill him and cut his head off.”

... part of another song.

Even by Arafura standards the sunset is a spectacularly vivid orange. Dhanggal worries because it doesn’t look or feel right.

She doesn’t say anything at the time, as the tents are pitched on shore at Rargala. For a while the darkness is eerie, dense and all enveloping. There’s not a breath of wind. But then, suddenly, we are lit by a pointillist blanket of stars, if not warmed by the smouldering fire upon which the mussels are baked.

Djalu sings to the campfire in a voice far more muscular than that in which he speaks. He claps his sticks while Vernon plays yirdaki. A customs aircraft circles overhead and inquires by radio of the boat’s captain who we are. De Backer, meanwhile, records it all, Søren shoots portraits and Ghost Patrol watches intently, creating mind images.

The next morning Dhanggal sits on a rock and fishes. I ask her where and how the Christian God fits into the story of her people.

Emphatically, she says: “God was there in the beginning and we always believed in the spirit. God the creator was always there and he is there in the songlines and in the stories of the land. And he has been reintroduced to us again through the missions. It’s not complicated for us.”

As we leave Raragala and sail back towards the hole in the wall, the wind begins to howl and the sea boils up into alarming criss-crossing waves and troughs. It’s going to be a rough crossing. For Dhangaal the sea is another sign – although of what, precisely, she is presently unsure.

Hama Pearl 11 threads back through the hole in the wall, the water a morass of intersecting whirlpools and the steep rocks on either side bearing curious graffiti: Dean and Shane, HMAS Wollongong. At the other end of this tunnel the sea dramatically churns up, and the boat begins repeatedly skipping and then smacking its hull down over the swell.

The family and the dogs go below deck. Many – including one of the dogs – are seasick as the weather and the seas continue to worsen. The captain, Kim, says that while conditions are taxing and demand caution, there’s no need at all for concern.

Then a few of us are invited into the bunkroom where the family elders stand solemnly in a tight semi-circle.

Djalu, in a Yolngu language, leads his wife and sister in prayer.

“God the almighty who controls power ... give us all and our visitors too a safe crossing over our waters and back to our land. Praised be to God and hallelujah.”

Hallelujah.

It’s many hours before the conditions subside and more, still, until the boat anchors back off Wallaby Beach. The family goes home and the rest of us sleep on board. It’s agreed that we will meet Djalu and his family at 9 o’clock the next morning when the men and boys will paint themselves in ochre and perform the West Wind ceremony. It is hoped that I will get more time with Djalu – an opportunity, perhaps, to ask him more about his past.

Djalu just gives and gives

We are on time this morning. But Djalu and his family are gone. Earlier a car drove through the Wallaby Beach settlement, tooting its horn – meaning somebody was dead (two members of the local Yolngu community have, in fact, died overnight).

We wait and eventually they return, having viewed and prayed over the body of one of the dead locals. The Yolngu men and boys, most stripped to the waist, are painted. So, too, are De Backer and Booth. Djalu chants, the yirdaki and the clap sticks sound and the men dance in a tight circle the sequences of the West Wind ceremony. The dogs seek shade. The women sit away and watch.

The ceremony celebrates the story – the song – of the sound leaving the yirdaki and going out to the island where Djalu was born, where it forms a big rock. The sound returns to its source as the healing west wind. It incorporates the songline about the yirdaki that De Backer had pondered.

Of his experience with the Yolngu, De Backer says: “Spending time with the Yolngu people you get a sense of the measured rhythms of things. For someone who is as relentlessly busy as I am, and who is always thinking ‘what’s next?’ it has been very instructive just to simply be where everyone else is without making plans constantly and maybe missing the core of things as they happen.”

A family member, Susan, asks me to drive her up to Ski Beach to collect Dhanggal, who is still sitting with and praying for one of the dead. As we drive I ask about the dead man.

“Oh, he was a very old man. He was very sick from the drinking and so on,” she says.

How old?

“Maybe 50. Very old.”

We collect Dhanggal and return to Wallaby Beach. She says the eerie orange sunset on Raragala, the wind and terrible seas on the return voyage were a sign, perhaps, that the two people would die.

“I’m not saying that I knew. I’m just telling you how I felt,” Dhangaal says. “And you have to take notice of what you feel.”

For my part I feel like I’ve barely scratched the surface of Djalu’s story. But that wasn’t really my task, and I understand completely why it’s taken the young director Strunin five years to make this film. He says that having interviewed Djalu many times now, he will be in a position to give a more factual account of his life in the movie, which he hopes will be released late next year.

“He’s referred to as the mystery man. He even refers to himself as the mystery man ... There’s a lot of speculation about his past. And I don’t think a lot of people know the exact details about his past. And I don’t really want to speculate about them ... because I might get them completely wrong. But one of the aims of this trip is to discover more details about his past and to hear more stories from him.

“I think what makes Djalu stand out to me, as a film-maker and just in general, in life, is that he’s just so generous in his attitude to sharing his culture – more than other keepers of sacred knowledge are. He’s like, ‘I will share this information with balanda and let the world know what we’re about.’ ”

Last night, just before he left the boat, Djalu performed a healing ceremony for all of us balanda. He blew into the yirdaki, while we individually held the other end to our chests and shut our eyes.

Afterwards, as he smiled his crooked smile and nodded, I could do nothing but hug the old man. Because whatever his past, these days he just gives and gives.

And now the day has denied me another opportunity to talk to – to interview – Djalu. It’s time for me to go.

I say goodbye to the enigmatic old man with his flowing white beard and long, wispy hair.

He holds both my hands, and says, “Please come back.”