It was a summer’s day 18 years ago and I was sitting in a car with my brother. We were in Kristiansand, the town my father was from, and had stopped at a junction and were waiting for a gap in the traffic so we could pull out. It was hot and overcast, and as we were waiting it began to rain. My brother switched on the wipers, I remember, and then without looking at me said: “You can write about this. No one’s going to believe it anyway.”

We were in Kristiansand because my father had died. And what my brother was referring to there in the car were the circumstances of his death. Neither of us had been in touch with him during his final years and although we were aware that a lot of strange stuff had been going on – once we were informed that he had disappeared and the police were out searching for him, only for him to turn up at a hospital a few days later, unable to walk having suffered some kind of temporary paralysis, for which reason he was sent to a treatment home for alcoholics – it all took place outside our field of vision and was therefore rather abstract. Our father drank too much, we knew that, but what that actually entailed was still something we were ignorant about. We didn’t want to know either. Our uncle called my brother one time and told us we had to do something and take care of our father, but we said no, that was out of the question, he had to look after himself. So it came as no surprise to us to receive word that he was dead. The shock came when we travelled down to Kristiansand, to the house in which he had grown up, where he had lived out his final years together with his mother, our grandmother. There were bottles everywhere, on the floors, up the stairs, on all the tables and sideboards, and the fine old home we had visited so often throughout our childhoods had degenerated completely. It looked like a squat. Our grandmother had found dad in his chair, but she was in shock. Confused, she shuffled about the house as thin as a skeleton, and when we asked her about what had happened she would tell us it had been morning when she found him, only the next moment to insist it had been evening. When we visited the chapel to see our father for the last time, his nose was broken and the pores of his face seemed to be clogged with blood which the staff of the funeral parlour had been unable to remove.

But the question of what had actually gone on in the house was totally overshadowed by the feelings it aroused. I kept crying all the time. The hatred I felt towards my father, a hatred almost as old as myself, was now completely gone. I wept and wept again – for him, for me, for us.

In the midst of this emotional chaos, one thought remained unaffected, as if contained in its own compartment, lucid and distinct regardless of what I otherwise saw or felt, and that was the realisation that I had to write about all this. That it was a great story.

I was 29 years old and in my suitcase was the manuscript of my first novel, due to be published that autumn. My brother had read it, and the first thing he said was that our father would sue me. The book was fiction, but there was enough of my father in it for him to be able to recognise himself and hit the roof, so my brother thought. This was what he was alluding to with his comment in the car.

We buried our father and carried on with our lives. My novel came out as planned, but although its publication meant I had achieved everything I had ever dreamed about, I felt no joy at the fact, because what I realised when my father died was that I had written that novel for him.

During the next five years I tried to tell the story attached to the house in Kristiansand, the story of my father’s decline and death. But it wouldn’t work. I had 800 pages of beginnings, none of which led me inside the inversion of light and dark in which I had existed during those days, none came anywhere near representing what I had experienced, neither on the personal level relating to my father, my grandmother, my brother and me, nor in what issued out of it in terms of how death affects the way a person looks on life and the world. After seeing my father lying there on a stainless steel trolley in the chapel, the very fabric of the world, the physical and material aspects of all things, seemed altered, even the people surrounding me, who suddenly appeared to me as bodies, physiology, biology.

Karl Ove Knausgaard as a child with his father and brother. Photograph: PR Image

After five years of trying, I got sidetracked into another novel, which I did complete. After it was published I returned to the story of my father, but again it resisted, I didn’t believe in it and lacked the strength to suspend my disbelief. Building a fiction room requires either great strength or great ignorance. To understand what I mean by a fiction room, one need only read Tolstoy’s War and Peace. I have read it twice and have been sucked inside on both occasions, as happens only with the greatest of novels – one invests greater and more numerous emotions in them than in real life itself, occasionally becoming aware that one is yearning for the rooms the novel opens, even for the characters it portrays. The many scene shifts, from the manors to the cities, from the ballrooms to the battlefields, and the changing viewpoints, characters developing on the basis of their various experiences and therefore continually facing each other in new ways, winding in and out of each other’s lives, without ever standing alone, yet also without knowing this to be so, since only we, the author and the reader, have access to all viewpoints at once. The last time I read War and Peace I sought to fill the void it left behind with another book from the same era and the same culture, Turgenev’s A Sportsman’s Sketches. It has practically nothing of what makes War and Peace such a great novel – no action, no intrigue, no plot, none of the grand scenes, no overall development as such, with peaks and troughs, and no central characters. A Sportsman’s Sketches is a collection of short stories, sketch-like as the title suggests, and anecdotal, revolving around a hunter’s encounters and experiences in the region in which he lives. Yet as soon as I began reading it I felt a very strong sense of proximity to the real Russia of the 1840s, a sense of the landscapes and people Turgenev describes being real landscapes and real people, that this was the way they actually were. It was as if Turgenev’s prose in some way tore through the plastic of the novel’s packaging, allowing that world to emerge in all its colour, populated by its own idiosyncratic characters. How that feeling of authenticity, or world-nearness, arises, I don’t know, but it is certainly rare and has nothing to do with Turgenev’s characters actually having existed, as opposed to Tolstoy’s, who did not. But it seems crucial that Turgenev’s characters and descriptions point nowhere other than to themselves, they are not a part of any larger series of events and are as such open in respect of everything but time and place, which comprise the very basis of our world experience. This utmost authenticity, this proximity to the world, is partially sacrificed by the novel in favour of the form itself, to make it possible to convey essential insights in relationships in particular, but also in sequences of events, psychological patterns and social structures. This must be why reading Turgenev straight after Tolstoy was such a shocking experience, coming so much closer to the landscape, the people, the culture, because that was the only place the reader is meant to go, to that particular barn, for instance, on that particular night, and it must also be why I didn’t believe in what I myself was writing all the while I was trying to tell my story in the form of a novel. I didn’t want to write about the relationship between a father and a son, I wanted to write about my dad and me. I didn’t want to write about a house where a man lived with his aged mother, like some variation on Ibsen’s Ghosts, but about that particular house and the concrete reality that existed inside it.

I was a novelist, and when I made use of experiences from my own life, they were camouflaged, part of the fiction

I didn’t know any of this during the years I sat trying to write that story, to me all writing is blind and intuitive, either it works or it doesn’t, and the explanation as to how a novel turns out the way it does is always a rationalisation after the event. What works always wins over in the end, seemingly of its own accord. So when, after 10 years of trying, I sat down one day and wrote a few pages about something that happened to me, something I felt so ashamed about I had never mentioned it to a living soul, and did so using my own name, I had no idea why I went there, nor did I to begin with connect it in any way to the novel I wanted to write, it was just something I did. I sent it to my editor, who described it as “manically confessional”, and I got the impression he took a step back, so to speak, because it was so disconcerting and not good in any literary sense. But there was something there, nonetheless, and both he and I saw it.

What was it? Firstly there was freedom. If I went in that direction, simply writing down things I had experienced, using my own name, it was as if all concerns about style, form, literary devices, character, tone, distance, at once ceased to exist and the vestments of literature suddenly became unnecessary posturing: all I had to do was write. But it wasn’t only the freedom of this that now fuelled the writing, it was also the unprecedented nature of it, the fact that to a large degree what I was doing was forbidden.

I was a novelist, I wrote novels, and to the extent I made use of experiences from my own life, they were camouflaged, part of the fiction. The option of abandoning that had never existed for me as a writer. I could bring the events of the novel as close to reality as I had experienced them, but to take that final step and write, “I, Karl Ove”, “my brother, Yngve”, or “my father, Kai Åge”, was something that had never as much as occurred to me. It wouldn’t be literature any more, would it?

Knausgaard outside his home in Sweden. Photograph: Katherine Anne Rose/The Observer

When finally I did it, it felt like a huge transgression. And not in any good sense either, because writing about myself using my full name meant there no longer being anything to hide behind. Moreover, who would be interested in my life, in the things I had thought and done, or that had happened to me? I was a nobody, or anybody. This is a very fundamental doubt I think all writers know, because submitting a manuscript to an editor is in itself both transgressional and embarrassing: what do I have that could possibly make another person want to spend time and effort reading about it? A work of fiction wears a veil of generality, it takes its place in a society alongside a host of other fictions from which it draws legitimacy. But this manuscript had no such legitimacy. Who would want to know that I had stood and pissed up against a pile of snow while listening to Talking Heads on a Walkman one night in the 1980s? Why even write about it? It wasn’t that I decided to write about my actual life as such, nor even to tell the truth. It was more the fact that writing under my own name, about my own reality, had its own set of premises, and its own particular consequences. Using my own name propelled me headlong into my own world, dominated as it was by trifles and inconsequential detail. This tiny quotidian universe was not intrinsic to any story and provided no narrative drive, but it was a part of me, and therefore I had to write about it. Another premise that emerged was that I had to be true to what I actually believed. That’s not difficult in a fictional novel, the writer can put his words into the mouth of a character, but in a non-fictional novel it’s different, because everything in it becomes binding. Writing about my brother, who means so very much to me, meant also having to write about how in our student days I would feel ashamed of him in certain situations. Would I be able to do that, knowing that at some point he would read it himself? How would it make him feel? This was true for all the people I wrote about, but it felt worst in his case, and I had to force the writing into being. This was my only moral compass, the physical resistance I felt towards writing about others. When the qualms became too many, the inner turmoil of conscience too great, I refrained.

I was trying to get words down on paper, before I started to get critical, before I started to think how stupid I was

So there I was, in an apartment in Malmö, with a wife and three children, writing about myself, flaring with shame and a burning sense of freedom. Only rarely did I think about anyone ever reading what I wrote. Mostly, I was trying to get words down on paper as fast as I could before I started to get critical, before I started to think about how stupid I was and how stupid the novel was, trying to exist within myself the way I was when I wasn’t writing. It was the only way to bring it about, to write without an audience, without readers, in a room on my own.

The purpose of the novel, its very reason and core, the death of my father, was still a matter I was unable to write about. The biggest problem with writing about something from one’s own life is perhaps exactly that – that you’re dealing with something that actually happened. An event is only true as it occurs, such an important part of its experience consisting in the fact that we are in the middle of it rather than outside, unable to see the overall picture, never knowing where it will lead.

What makes a novel feel vital is when it comes into being as it is written, in much the same way as the moment occurs as it is lived. So what I was doing was writing blindly, unknowing of what would come next. I started with something that happened when I was 16 and I was going to a New Year’s Eve party with a friend. The story could have been told in two sentences – we had a lot of trouble trying to get our hands on some beer, when we got it we hid it in the snow for a few days, and when finally we arrived at the party we were turned away at the door. But in the book that episode took up a 100 pages. While at the time I had no idea what I was writing or why, it is abundantly clear to me now: I was writing about life the way it appears to an uninformed 16-year-old, in all its enormous banality, and only when I had done so was it possible for me to write about my father’s demise, about death in all its enormous banality. I could then enter the house along with my brother, I could describe what we saw and what we did, because now those events represented nothing more than themselves, being so much a part of my own trivial experience. I was no longer looking at Death, but at death. The person who died wasn’t my Father, but dad. And Yngve was Yngve, not my Brother, not Abel.

I was unprepared for the storm that broke. My father's family wanted the book stopped

The novel was to have ended there, but it felt like I had described only the smallest fragment of life, at the same time as I had found a language for my non-narrative, day-to-day existence, and so I carried on, letting the text slip inside the life that was all around me, at a time when I had become a father myself, because that experience was quite as defining as death, and its natural counterweight. That’s how I experience life, as an ocean of quotidian existence in which meaning is diffuse and difficult to grasp, and then comes death with its unprecedented concentration of meaning, or else love or birth. By the time I delivered the book to the publisher it amounted to some 1,200 pages. They suggested putting it out in 12 parts, one a month over the course of a year. I loved the idea, not least because it reminded me of the rock band the Wedding Present releasing 12 singles in 12 months, but it turned out to be too complicated and too much of a risk, so we landed on six novels in a year. I could split the existing manuscript into six, but decided instead to divide it into two and write four more, to be published consecutively the same year. In that way, at pistol point, I could immerse myself in childhood, then pass through youth and my student days to approach, as if from below, the crux of the novel, my father’s death, which in the course of such a long sequence of events would have totally altered character and taken on a completely different significance than originally envisaged.

Knausgaard with his brother Photograph: 1996-2001 AccuSoft Co., All righ/PR IMAGE

I sent copies of the first volume in manuscript form to the people I had written about, expecting some to be annoyed or angry, but the storm that broke was one for which I was quite unprepared. My father’s family wanted the book stopped, and the ensuing conflict became public. No one knew what a court case might entail, and the publisher hired a firm of solicitors to read everything I wrote about anyone who wasn’t me. The book I had written about myself, which I had seen as an experiment in realistic prose, infinitely dull and uninteresting to others, became a media story for some months in Norway. My picture was all over the front pages, a moral debate raged, and everyone wanted to read what I had written. I closed my doors, kept away from the papers, TV, radio. I told friends and family to keep me in the dark, I needed to write, to retain that space for myself, something I only partially succeeded in doing. Reporters were contacting everyone I had written about. They loitered outside the houses of my friends, waiting for them to emerge. They knocked on the door of my mother-in-law and scared the life out of her. They phoned her ex-husband, a man of more than 80 years living a secluded life in a forest, wanting to know his reactions to what Karl Ove had written about him. It was ironic. What I had written about were my thoughts and feelings, the most private part of any person’s life, only for them to be exposed in that most superficial of realms, the media.

The sixth book in the series was about the consequences of the first five, the reactions of those I had written about, the response of the media, the impact on me and my family. That book came to more than 11,000 pages. Four years have now passed since it came out in Norway, and I have travelled around the globe and talked about it as its translations have appeared in each new country. It is a soul-devouring task, the division between me and my literary self being so slight. One thing I know is that I will never do anything like it again. My plan now is to write something completely different. I may even visit the villages of Russia and see what the last 160 years have done to reality there since Turgenev tramped around with his rifle.

• Translated by Martin Aitken. Some Rain Must Fall: My Struggle Book 5 is published on 3 March. To order a copy for £14.39 (RRP £17.99) go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99.