If there's one thing history has taught us, it's that humanity doesn't always live up to its own lofty standards—or even its more lowly ones. Any of the supposed civility found in the whirring mechanics of the modern world, or crumpets shaped like cute Easter animals, fails to obscure some immutable human foibles. One of those, surely, is lying.

The biggest recent evolution in lying boils down to one phrase, the 2016 Oxford Dictionary word of the year: post-truth. Donald Trump didn't invent lying, or even the concept of weaponised fibbing—Machiavelli emphasised the ‘value’ of political misfeasance way back in the 16th century—but he did usher in the age of the untouchable buffoon. Either half of the U.S. population purposefully rejected reality four years ago, or something else is afoot. Seemingly, we're all prone to dismissing reason for the lure of sensationalism.

Our rocky relationship with the truth is a common preoccupation for filmmakers, but few have tackled it better than Akira Kurosawa with Rashomon, a film approaching its 70th anniversary this year, offering a pointed prognosis of our current political status quo. First screened at the Venice Film Festival in 1950, the film took home the Golden Lion, the festival's highest prize, and heralded Kurosawa's emergence on the international stage. Why? Rarely since the silent era had cinema so artfully matched its photography with its philosophy.

Rashomon is less a whodunnit than a whydunnit. Centring on the grisly murder of a samurai in the forests of 8th-century Japan, we first meet three travellers taking shelter under the ruins of the Rashōmon city gate. Two of them, a woodcutter and a monk, are in a state of rapt disbelief following the judicial inquiry, with the former (who found the samurai's body) reduced to repeating, "I don't understand. I just don't understand." The last to arrive, a sceptical commoner, functions as the audience surrogate.

As the film moves beyond the framing device into the trial itself, the sequence of events is explained, in turn, by the notorious bandit Tajōmaru, the samurai's wife, and the deceased samurai (as channelled by a croaky court-appointed medium). It's confirmed early on by Tajōmaru himself that he killed the samurai and raped the samurai's wife, but each person's rendition hinges on wildly differing interpersonal dynamics and tone. Less an inquisition into murder or sexual assault than a bureaucratic facade, each retelling is a performance built on appeals to existing prejudices. Sound familiar?

In recounting his day in court, the woodcutter seems particularly beside himself, frozen large in the frame with glassy eyes. We initially assume it's the gruesome, unusual contents of what he's heard, the "strange story" that has left him so shell-shocked, but the reality is far less peculiar. His existential crisis has instead been triggered by the persistent and flagrant lying of all involved, and his own inaction in correcting them; he's later revealed to have been a direct witness to the samurai’s death. Perhaps more than that, the woodcutter is shaken by the idea that his own memories may carry with them the same biases as the defendants he’s watched lie.

This shock only lands harder for modern-day viewers, since it's difficult to imagine a time when people might be so unnerved by convoluted lies. A 2019 survey of 1,000 members of the British public by JournoLink found that 45% believed they encountered fake news every single day. Far from widespread rejection, our only course of action has been to inoculate ourselves through submersion. A study in Psychological Sciencefound that the more we read the same fake headline, the more we subconsciously view it as legitimate. We value loud repetition over the truth.

So, if we can't identify authenticity with unlimited resources at our fingertips, how can we act as judge, jury and executioner based solely on ‘He said, She said’? Regardless of competency, Kurosawa frames the audience as such, positioning the camera in the seat of the silent court and forcing us to face each defendant as they make their case. In a manner remarkably similar to a social media lurker, we stare at a screen, attempting to decode fact from fiction. The farce? There is no right answer.

It's the film's two most amoral, cynical characters that will chime the loudest for contemporary viewers: Tajōmaru, played with a characteristic swagger by Toshiro Mifune, and the misanthropic vagrant whose benefit this whole tale is for. Tajōmaru flaunts his criminality so brazenly it almost seems acceptable; within seconds he confesses to being the murderer, before attributing his crime to a whimsy of nature: "If it hadn't been for that wind, I wouldn't have killed him." There's an air of the Tory drug-use confessions to his absurd frankness, though his untouchability comes from the inevitability of his fate, rather than class. You sense Tajōmaru probably wasn't trying to score points with the youth voter.

After candidly recounting his atrocious acts and motives, there is, however, a moment of regret for Tajōmaru. "I totally forgot about it. That was foolish. The biggest mistake I ever made!" he roars with a glint in his eye, when pressed on the location of an errant dagger with a pearl inlay. Tajōmaru might be totally morally bankrupt, but there's a bizarre honesty to his darkly comic act. The vagrant, too, has no qualms about owning up to his own disreputability, remarking bluntly, "I don't care if it's a lie, as long as it's entertaining." He might as well be reading the Twitter bio of a diehard MAGA believer.

If even the most dastardly characters in Rashomon are too transparent to be analogous to Trump, then who offers the closest parallel? As a rampant narcissist, the politician is more in tune with the supposed victim: the dead samurai. Both occupy trusted, prestigious positions in society, and yet their behaviour is mostly superficial. Much as Trump places an undue onus on performative masculinity—yanking arms during handshakes; referencing the genitalia size of other world leaders—so too does the samurai's trial from beyond the grave only serve to assert his masculine honour, contorting the tale so it ends with righteous suicide rather than a plea for his life. The fact that no-one questions the legitimacy of the medium channelling his spirit isn't a million miles from Trump's poorly policed online slander.

Ever the auteur, Kurosawa was aware that the sticky moral quagmire of Rashomon was more relevant to contemporary quandaries, stating in an interview with Bert Cardullo, "I, Kurosawa, live in modern society. Thus it is normal that my 'historical' films contain 'modern' dimensions." With Rashomon, the filmmaker made it abundantly clear that he thought anyone and everyone was subject to lying. Accordingly, he didn't trust any of his characters to symbolise the search for a higher truth, not even the pious Monk. Instead, he chose the sun.

As the audience investigates each storyteller, we stare at them from a shady covering as they're framed against the stark white of the sunlit stones, even if the sun doesn't prove all that illuminating. The glaring sunlight doesn't embody objective truth, but instead signals clarity and scrutiny in the face of manipulative spectacle. In his autobiographical account of filming Rashomon, Kurosawa wrote:

“I decided to use the Akutagawa ‘In a Grove’ story, which goes into the depths of the human heart as if with a surgeon’s scalpel, laying bare its dark complexities and bizarre twists. These strange impulses of the human heart would be expressed through the use of an elaborately fashioned play of light and shadow.”

Everything pivots on this interplay of light and dark. In the ambiguous pall cast by the trees, men are more prone to act out their base desires. In the light, they pause.

Kurosawa shows this early on with one of his most famous shooting innovations; pointing the camera squarely at the sun, albeit obstructed softly by the forest overhead. The light blooms and diverts, scattering amongst the leaves. Once freed from its probing rays, we see man devolve into pure id: raping, murdering, kidnapping, thieving, and lying about all of the above. It's a simplistic message, but a potent one: that article you scanned over earlier, or that tweet you're itching to retweet, try exposing it to the cold, hard light of day, and see if it loses its lustre.

What Kurosawa realised above anything else is that storytelling is an appeal to emotion, for better or worse. Throughout history we've frequently been led by our hearts over our minds, but the explicit rejection of experts by right-wing figureheads the world over has come at a pivotal point, as the negative effects of capitalism, climate change, and even the mundane everyday hang ever heavier over us. In this sense, post-truth politics act as a shrewd inversion of cinema. Where the best films distort and exaggerate reality to provide pathos, the greatest manipulators in a post-truth era use simplistic, inflammatory rhetoric to goad our worst fears and impulses. Sadly, there's not always a humble woodcutter there to set things straight.

Rashomon is currently streaming on BFI Player