
There’s something going on in this novel which bears comparison to the conceit of the Apple TV series Severance: a world of innies and a world of outies, with formally separate memory streams and a narrative process by which the two are potentially ‘re-integrated’ even as it becomes perhaps a little less clear which of the two is the actual ‘underworld’.
Modern long form TV seems above-averagely fascinated with journeys to and from an isolated, relatively constricted alternative reality or inframundo: Lost played with this scenario and a host of related motifs for six seasons, before finally settling on what was probably the most banal of available symbolic resolutions.
The ancients were of course fascinated with these transitions into mythological realities which abruptly coalesce for dramatic purposes with our own. There’s Virgil’s Aeneid, and the Cretan labyrinth of course, and over here we have the central narrative of the sacred book of the Quiché Maya — Popul Vuh — recounting the away games of Mesoamerican ball played by the hero Twins against the Lords of Xibalba.
I am fairly certain this isn’t Murakami’s best novel, but it strikes me as undoubtedly his most profound that I have read to date. However, it may well end up being hard for many to appreciate just how interesting and original it is, because it is long and packed with passages of workaday language (especially in the English translation).
Yet beneath the verbiage, Murakami’s city with its uncertain walls has a range of qualities which set it apart from other hidden worlds one might stumble across in modern literature....
1) It’s an imagined place — a story with a back-story — which sometimes assumes the properties of a real place
2) It is a hard-working multi-layered metaphor: at its simplest, for human consciousness and its processes for interfacing with the unconscious.
And in this sense the latter assumes the role of the underworld’s own underworld, with dreamland forming something like an interstitial space between the mundane world and the wobbly-walled city.
Murakami is noted for his blend of east and west — or perhaps for the western cultural patina he lays upon eastern intuitions — and here we can see how European ideas, like those of the psychoanalysts, are made to connect with native Japanese notions, such as those which emerge out of Shintoism. (The English translation, not the Spanish, works the title of Miyazagi’s film Spirited Away, into one passage, in italics.)
3) The city is seemingly subjectively-constructed, for two (apparently) distinct individuals can perceive it differently from both within and without.
Something similar is intimated — though never explicitly — in Dante’s Inferno and other western tales of descent into worlds caught between literal and figurative existence. These tend to have been rather obviously customised to the cultural perspective of the poet/author, in Dante’s case that of late medieval Florence.
Murakami also hints at a kind of Chinese Whispers effect here, whereby an individual can experience the structure and content of the city according to the misremembered or re-constructed version of another.
4) A representation of what a world might be like if somehow tailored for people who have refrained from engaging with the actual world.
5)
It is a place where time happens but has no meaning and remains somehow
'anchored', compared here to turning the pages in a book and finding
that the number never changes.
6) And lastly, it functions as a kind of laboratory for testing Murakami's notions of self-hood and perennial anxieties such as incipient transparency and/or the existential version of imposter syndrome.
I may be projecting a little here, but I detect that Murakami understands the self as variations on a theme, at least two, if not more, and not all of which may be present within the sheet music book to hand at any one moment.
Each individuality is always a multiplicity and some of our multiples may right now be away getting by in another world.
At the very least every person is a packaged duality, yet not precisely in the way Descartes saw it. Murakami himself seems a little uncertain at what he is getting at here, and the novel is better for it.

People and places have shadows, which sometimes rebut each other and on other occasions align and merge. This phenomenon is loosely mapped onto the interplay of the subjective and the objective, and this leads to a discernment according approximately with one of my own: the possibility that we might somehow, sometimes be able to project the uncanny into the world around us.
As Anaïs Nin said Nous ne voyons pas les choses comme elles sont. Nous les voyons comme nous sommes, though I don't think that's quite what she meant.
Only
one of the basic pair can cross over between realities. There is a sense here
that for some people the distinction could be more demarcated, but for others the
barrier between them is far more permeable to the extent that at any one
time a sentient human cannot be sure it is him or herself leading this
life or whether the shadow is filling in while the ‘real’ person goes off for a
metaphysical wander.
Yet these essentially fused beings are sometimes
also able to share knowledge and sentiment when apart.
Many years ago as an undergraduate I attended a fascinating series of lectures on popular beliefs in early medieval England. Inhabitants of small rural communities tended to imagine that objective reality started to blur at the physical edges of their village. They understood that certain members of their community always had one foot in this supernatural shadow reality: those whose job it was to wander, like hunters, but also some who hardly ever left home, like children. Dogs too could pick and choose which world to perceive. These ideas have been very sticky and often form the basis of Horror genre treatments in contemporary films, and in this novel Murakami also suggests that certain individuals have privileged access to existential ambiguity (though he'll swap dogs for cats). Yet the personages of this age old 'superstition' have been seemingly placed within an inherently more vague yet sophisticated cosmological geography, where the netherworld is neither simply down below us or out in the woods somewhere.
In the Afterword Murakami explains how important these fancies have always been to him. Indeed, this big book started long ago as one of his earliest short stories which appeared in the literary magazine Bunguku-kai c1980, and then, once established as a writer, he approached it five years later, from a parallel perspective, appropriately enough, in Hard-Boiled Wonderland and the End of the World, a novel I am yet to tackle.
Now he has returned to what he sees as the core conceit because he suspects he has never quite nailed it, perhaps because underlying it there is a shimmery set of convictions which one can only catch sharper glimpses of by changing perspective. The substantial and its shadow are sometimes hard to tell apart.