The widely read and rarely seen crime writer Keigo Higashino said in a rare interview five years ago that his work is driven by “the old-fashioned Japanese sense of loyalty and concern for human feeling.” This is his USP, really. It’s a theme that runs diligently through all his novels, at least the ones in translation, and it’s almost comforting. There is a strange sense of calm even as someone is murdered, rarely any explicit violence, certainly no political incorrectness, and none of the X-rated stuff that charges a lot of the dark contemporary crime fiction.

Reading a Higashino mystery is like watching censored cinema. You won’t be scarred. You could let your teen read it. You may even feel quite a bit of empathy for the killer. You won’t have nightmares of deranged killers.

So, you won’t feel a serious depth in Higashino’s writing. But you will feel a rush of crime-solving vigour. And that’s how it goes even in his newly translated murder mystery, A Midsummer’s Equation, part of the Detective Galileo series featuring the eccentric physics professor Manabu Yukawa and his detective friends Shunpei Kusanagi and Kaoru Utsumi. There’s a murder, lots of scientific experiments to fill in crucial evidence, a very humane killer, some chuckle-worthy banter, a reasonably convincing plot, a decent twist. Higashino is dependable like that.

A bit formulaic? Sure. But still quite thrilling.

The murder

A former cop is found dead at the bottom of some cliffs at a summer beach resort, Hari Cove, a few hours from Tokyo. Who would want to kill a seemingly noble cop with no real enemies? Yukawa, the tall, bespectacled professor you will remember from novels like Salvation of a Saint and The Devotion of Suspect X happens to be at the same resort town, attending a conference on a planned underwater mining operation. The mining business has got the otherwise jaded and fallen-on-hard-times town buzzing, and the natives are divided on whether the operation could save their economy, or ruin the pristine waters of Hari Cove.

We learn early on that the death of the cop, Masatsugu Tsukahara, was caused not by falling on the rocks but by carbon monoxide poisoning, and, gradually, the suspects are lined up. What was the former cop’s connection to the mining operation? Could he have been killed by Senba, the man whom the dead cop put behind bars years ago? Or by his wife? Perhaps by someone at the family-owned Green Rock Inn at Hari Cove, where he was staying? Or even by Sawamura, the journalist-activist passionate about Save the Cove?

As is standard procedure in most Higashino novels, the past is thoroughly dug up, and what happened some 15 years ago seems to be the key to this mystery. The cops are soon making connections between suspects who didn't seem at all related at first glance.

The investigations

This is a mystery neatly laid out, like setting a table out for guests. It’s also more populated and fragmented compared to Higashino’s previous novels, with the plot unravelling gently across a number of investigating centres. Several different teams of detectives are on the trail of the murderer at Hari Cove and Tokyo, where some of the clues lead to, while Yukawa is busy working his genius mind at ground zero, close to where the former cop was found dead.

Much of Yukawa’s time is spent puzzling over how the man was killed exactly, and the science behind it. In the process, he plays his part of the professor-mentor gamely, indulging in some quirky, complicated experiments with the novel’s most likeable protagonist, the pre-teen Kyohei. The young boy, nephew of Green Rock Inn’s owners, is at Hari Cove for the summer, sent over by his very busy parents back in Tokyo.

We read part of the novel through Kyohei’s perspective, which is one of its most intriguing strands, resting on a child’s slightly vague point of view – innocent, only mildly curious about the death, yet deeply involved at a subconscious level. Kyohei finds Yukawa both the weird guy who obsesses over how stuff works and the only one at Hari Cove who really gets him. A sort of unlikely playmate, a proxy parent, without really treating him like a kid.

Kyohei tells Yukawa about his motion sickness, which makes it impossible for him to get on a boat to go 300 metres out at sea, where the clear water allows the most wondrous sights of Hari Cove at the bottom of the ocean. In his trademark there-has-to-be-a-way style, Yukawa makes science work, demonstrating a customised experiment, and gets Kyohei a glorious view of exactly what he wanted, without even stepping away from the beach. The sea fills the novel with deep human connections – between the pre-teen and the scientist, a father and a daughter, the natives of the town and their past and future.

This mystery has a slow burning energy, with few threads to pick on early in the book. Once the detectives track down Senba, the man the dead cop once arrested and seemed to have a strong personal connection with, the pace quickens. The core mystery is sort of easy – and a bit predictable – to sniff out many pages before the big revelation, yet Higashino holds a few cards close to his chest, so there are some surprises in store, some clues we miss.

Yet, the novel lacks the intense psychological play of Malice, about the death of a writer and an unreliable narrator, which has some nifty structuring and solid twists. This one is also far less complex than The Devotion of Suspect X, with few tense moments and none of its outrageous plotting and inventiveness. For a Higashino novel, this is good, but certainly not among his best.

A Midsummer’s Equation, Keigo Higashino, Translated by Alexander O Smith, Little, Brown.