For a purveyor of crime and espionage fiction, it seems fitting that Mai Jia should be so difficult to sum up and pin down. Some critics have called him China’s answer to John le Carré. Others, in what is surely a backhanded compliment, hail him as China’s Dan Brown. Muddying the water further, the writer Tash Aw claims Mai’s style is a blend of Kafka and Agatha Christie.

It is fair to say his books – all huge bestsellers in China – are a composite of all of the above. However, his first novel, a thriller published in China in 2002 and published in English in 2014 as Decoded, had definite le Carré leanings. (Like le Carré, Mai worked in a previous life in the secret world. Also like le Carré, Mai Jia is a pseudonym – the writer’s real name is Jiang Benhu.) In the Dark, his latest novel to appear in English, is another foray into the cloak-and-dagger realm, specifically a return visit to Special Unit 701, the cryptography department of China’s secret service.

The book’s prelude comprises a classic thriller conceit: a man in the wrong place at the wrong time. A businessman – who, we are told, is called Mai Jia – flies to Beijing and, on landing, is questioned by police about the two passengers he shared a row with on the plane. Some days later, those two men make contact with him and ask him to visit them at their work facility out in the mountains. The wrong man becomes a singled-out man. He makes the journey and arrives at the shadowy Unit 701 on “Declassification Day”, a day on which he is able to search archives and listen to personal accounts of covert missions. What follows are his findings: four tales about four intriguing intelligence operatives.

The first and second stories are the strongest, and deal with the recruitment and varying success of two remarkable individuals. In “Wind Listeners”, a spy tracks down and enlists a blind, simple-minded man who has exceptional hearing. He is “able to distinguish accurately the parentage and sex of anonymous dogs by their barking, to listen through the dense web of airwaves and pick out those frequencies we needed to find”.

In “Wind Readers”, the longest and most substantial tale, a brilliant mathematician is brought on board during a period of intense cross-straits tension with Taiwan and tasked with breaking a complex, high-level code. Both recruits save the day and safeguard the nation, but go on to meet tragic ends.

Mai’s third story features another talented eccentric, this time an old man who can crack codes in his sleep. The final tale, “Wind Catchers”, is subtitled “A Vietnamese Ghost Story”, and is likely to appeal only to readers who have no truck with the following line: “From here on, what I’ll tell you about happened after I died.”

In the Dark has all the hallmarks of a thriller. It comes with short punchy chapters, imagery that veers from no-frills to trite (“these events kept twisting through my mind like a snake”) and a glut of smokescreens and betrayals, false identities and faked deaths.

And yet for all that, it doesn’t thrill, at least not in the sense that we are tearing through pages while biting nails down to the quick.

Instead, its immense readability derives from the pervading air of mystery, the Orwellian depiction of Chinese state security (“whosoever entered our division … would become part of the nation, part of the People, but they would cease to exist as individuals”) and a range of exotic insights, from Chinese history and proverbs to delightfully arcane cryptography terminology.

All four stories lack what Graham Greene called the human factor, but this is clearly a deliberate ploy of Mai’s. His creations are indoctrinated spies, slaves to the regime, some of them “revolutionary orphans” brought up by the Party; all toil in their cocoons, have little time for friendships and believe marriage is “an adjunct to your work”. Mai’s mathematician is the only character that professes love for another, but her advances are rebuffed. A romantic relationship, she learns, is “bourgeois corruption”.

Fascinating rather than gripping and all the better for it, In the Dark satisfies as a twisting, riddling and compellingly original exploration of thwarted geniuses and restricted lives.

Malcolm Forbes is a freelance writer based in Edinburgh.