The author admits this himself, and often claims to be a bit baffled by his ongoing compulsion to write, given that he has no particular points to make, nor even any stories to tell. He gets up at four every morning, sits down to his desk, and starts composing as if he were still dreaming. If the results seem duly dreamlike to the reader, it's because they strike a distinctive double chord of banality and surreality that feels familiar from our own subconscious netherworlds, where domestic or prosaic scenarios give way to sexual interludes, logical impossibilities and memories both true and false, all presented matter-of-factly.
Murakami's latest novel, Colorless Tsukuru Tazaki And His Years Of Pilgrimage, spends more time in what we might call the real world than many of his past works. But it also gives more thought and weight to the idea that our dreams may be no less real, and that, as Salvador Dali suggested, our responsibilities begin there. The title character is a designer of railway stations, living an empty and lonely life in Tokyo.
As a teenager in his hometown Nagoya, he belonged to a tight circle of five friends, all of whom except Tsukuru had names that connoted different colours in Japanese (his own name means "to make" or "to build"). At the age of 19, after graduating high school, the others cut him off abruptly and completely without any given reason, leaving Tsukuru on the edge of suicide - which Murakami typically describes as an actual place, a twilight precipice with its own weather and wildlife. Now 36 and a functioning if solitary adult, he is prompted by a prospective girlfriend to track down and confront his former friends, and thereby resolve his lingering "emotional issues".
She actually uses that phrase, and a lot of the book is given over to their forthright conversations about Tsukuru's psychological baggage, rendered in a language that rarely sounds like real speech or even fictional dialogue, and sometimes wanders pretty deep into the mind, body, spirit section of the bookshop. "You can hide your memories, suppress them, but you can't erase the past that produced them …"
As ever with Murakami, it is hard to tell how much his affect has been flattened out by translation, but at this point it is surely fair to say that nobody reads him for the writing itself. In the last 10 years or so his popularity has spread from a phenomenal Japanese fanbase to a worldwide cult because of some contagious and addictive quality encoded between the lines, or in the silences between the notes.
While there is not much music to his prose there is a lot of talk about it, with Franz Liszt's Years Of Pilgrimage suite repeatedly called on to express Tsukuru's melancholy, or " … the groundless sadness called forth in a person's heart by a pastoral landscape", as the character himself says when trying to articulate the meaning of the Liszt piece Le Mal Du Pays.
And it's something like this feeling that sustains the reader through any number of mundane digressions into Tsukuru's swimming routines, travel arrangements, clothing choices and menu selections. "The croissant was too sweet, but the coffee was strong and delicious," we are informed, as our hero takes a snack break before a final reckoning in Finland.
There are many sexy dream sequences too, which seem both Freudian and Jungian, but also pathologically Murakamian.
Though as passive in the waking world as all the author's previous protagonists, Tsukuru's repressed desire and rage raise various dark suspicions in his sleep, which may or may not help explain why his old friends abandoned him.
In the end, he gets a straight and brutal answer to that question by simply asking them, but there is no resolving the bigger mysteries at stake: why do people have to change, and age, and grow apart, and die?
The grown-up answer is "just because", but Murakami has never been satisfied with this, and there is something childish or adolescent about the way he keeps on asking, and this may even hold the secret of his strange appeal.
More by intuition than design, he seems weirdly attuned to the existential aches and pains that first flare up brightly in youth, then dull to a low throb with age.
Though Murakami is now in his mid sixties, his most recent characters have been in their teens and twenties, their lives still open books, albeit cryptic ones.
But Tsukuru Tanazaki is just on the cusp of his middle years, and there's a lamentation sounding through this novel - so quietly that you don't even notice until you find yourself profoundly moved.
The oblique magic of his early work has now faded a little, but Murakami seems to know exactly what he's lost. "That amazing time in our lives is gone, and will never return," says Tsukuru's long-lost friend Kuro (or "black").
"All the beautiful possibilities we had then have been swallowed up in the flow of time."