Our protagonist, or at least the first of several “MEs”, is Hitoshi Nagano, a slacker who sells cameras in a superstore rather than pursue his dream of being a photographer. Self-centred and passive, his character is summed up in the moment he watches his furious mother exit his flat: “Reason told me to follow her, but my indifference won out.”

Similar apathy marks the novel’s jumping-off point: “I stole the cell phone on nothing more than a spur-of-the-moment whim, without any sense of wanting to do anything with it.” Hitoshi is in a McDonald’s when he encounters Daiki, a bumptious businessman whose carelessness causes him to lose track of his phone (he is busy boring two subordinates with a tirade on eco-bags and his bowel movements).

Having read a few of Daiki’s messages, Hitoshi decides, with a characteristic lack of logic, that “I really couldn’t ditch the mobile phone without pulling off some sort of prank”. Driven by a glimmer of sympathy for his victim, he decides to hoax Daiki’s mother: both, he concludes, have “overprotective and meddlesome” matriarchs.

Being Hitoshi, he dithers over the exact nature of the trick. Should he e-mail news of Daiki’s bowel movements or some­thing else? The decision is taken out of his hesitating hands when Daiki’s mother calls.

The ensuing conversation is a scrambled version of ore ore. Daiki’s mother mistakes the voice that answers, gives health advice (“stick to your vegetables”) and offers extra­vagant financial aid. Instead of exulting in his criminal triumph, a paranoid Hitoshi feels the tables have been turned on him, pointing out that “at some point the joke had turned real, and I missed the point of no return”.

Here begins the fun Hoshino has with Hitoshi’s identity. “Even when the conversation was over, the sense of not being myself lingered,” he says. “Feeling removed from my normal reality, like a cat in a strange house, I kept waiting for another call from mother.”

When she does eventually phone and asks him to visit, Hitoshi destroys the phone, either from fear or conscience, and gains brief existential respite: “I had the distinct sensation of having regained my true self.”

It doesn’t last long. Hitoshi returns to work, argues with his overbearing boss, and then goes drinking with colleagues, complaining to them about his demanding parents. Returning drunk to his flat, he discovers none other than Daiki’s mother waiting to interrogate him in the belief that he is Daiki. When a panicked Hitoshi thinks, “Get me back to reality”, the reader shares his sense of disturbance.

From here, the cases of mistaken, shaken and shifting identity multiply with a speed that feels at once surreal and, thanks to Hoshino’s clear-sighted narrative, inevitable. By adopting someone else’s identity, Hitoshi feels a strange release from his own, and gains “a measure of self-confidence”, he notes with no little irony.

This is quickly undercut when Daiki’s mother shows him a photograph of her son – and he sees not Daiki but himself. In case your brain isn’t tilting by this point, the set-up has a final sting in the tail. Prodded to visit his own mother “with as much cheeriness as he could muster”, Hitoshi finds someone waiting for him: “It was the man I’d been seeing no end all day. It was a ME.”

That indefinite article proves significant, as Hitoshi begins to encounter other appa­rent­ly like-minded MEs, and not just the ones competing for possession of his own soul. “It was me and yet had nothing to do with me,” he says.

In one respect, the novel’s exploration of authentic selfhood is as old as literature itself. I found myself regularly reminded of Book III of Ovid’s Metamorphoses and Narcissus’ declara­tion upon recognising that he loves his reflection: “I am he.”

Hitoshi is certainly guilty of self-love, but mostly self-loathing, as he struggles to reconcile his own desires, ambitions and limitation with “the unreasonable expectations imposed upon him” by parents, society and his own perception of parents and society. “Family is definitely other. Families are where otherness begins,” he argues.

It’s not hard to read ME as a critique of contempo­rary Japan. In what feels like a pointed motif of cultural schizophrenia, Hitoshi’s iden­tity crisis includes regular, guilt-ridden visits to McDonald’s. Hoshino’s central theme, however, is treading a path through crises of indivi­dualism, masculinity and nationalism.

Hitoshi’s sense of self steadies, again with unacknowledged irony, by finding others – young, male, dissatisfied – who share his frustration with life: parents who “saw only what they wanted to see – and that was the image of successful people in their midst. To them being an individual simply means some­one who has come up in the world”.

The resulting formation of a “ME” society, in which “MEs” share “perfect mutual understanding”, is under­stand­able – and, by definition, doomed to failure: the inescapably human fissures, contrasts and contra­dictions that comprise each individual identity cannot but break the commune to pieces.

Hoshino is not unsympathetic to his characters or their plight: Hitoshi’s loneliness and sense of powerlessness over his life are felt by many millions across the world. The genera­tional angst tearing at Japanese society is also present in China, Trump’s America and Brexit-rattled Europe, as the young complain that their future has been sold by an oblivious ageing population.

It is hard to resist Hitoshi’s idealistic hope to be “part of a truly larger self, always with the full, shared range of our human feelings and thoughts. As long as that condition held, WE would endure.” Yet the first part of that final sentence (“As long as that condition held”) rings the death knell for his ambition. As Hitoshi later hints, such communal feelings require either narrow political solidarity or a kind of robotic obedience: “We were supposed to be comrades, in sync with each other twenty-four hours a day.”

Hitoshi, like any 21st-century tech obsessive, would love life’s chaos to mimic the programmed order of a computer or camera. He explicitly views identity as something he can switch on when it suits him or off when it unnerves him.

The triumph of ME is to satirise the frustrations of Hitoshi’s narcissism (his isolation, selfishness, sadness, apathy) without losing sight of the human condition that underpins it. Life is hard, Hoshino seems to say, in part because people are complex. And, really, would we want it any other way?