The Devotion of Suspect X (Detective Galileo, #1)

by Keigo Higashino

There were four employees at Benten-tei. Yonazawa was the manager, assisted by his wife Sayoko. Kaneko, a part-timer, was responsible for making deliveries, while Yasuko dealt with all the in-shop customers.

He was like the thin crack in her apartment wall. She knew it was there, but she had never paid it that much attention.

‘Ms Hanaoka,’ Ishigami went on. ‘It’s very difficult to dispose of a body. A woman can’t do it by herself.’

Without people to question the status quo, how can we ever hope to arrive at truly rational decisions?’

It was one of the most famous problems in mathematics, first put into print in a paper in 1879 by one Arthur Cayley, who had asked the question: are four colours sufficient to colour the contiguous countries on any map, such that no two adjacent countries are ever coloured the same?

‘That’s what happens when you free people from the restraints of time. They make their own rigid schedule.’

One thing Yasuko had discovered during her time working as a hostess was that men who were good listeners and truly cared about other people’s problems generally came from happy homes.

‘I’m sure they do. But that isn’t true for the support team for those racers. They run detailed simulations over and over to find the best places to accelerate – that’s how they work out a strategy. And in order to do that, they use differential and integral calculus. Even if they don’t know it, the computer software they’re using does.’

‘Which is harder: devising an unsolvable problem, or solving that problem?

Ishigami watched him go. A feeling rose inside him, making him queasy, as though an elaborate formula he’d thought was perfect was now giving false results because of an unpredictable variable.

‘Which would mean that Ishigami had forgotten to wipe it for fingerprints. You really think Ishigami would have made such a simple mistake? Ishigami the Buddha?’

‘Maybe you’re overthinking this. That guy might be a genius mathematician, but he’s certainly a novice murderer.’ ‘They’re the same thing,’ Yukawa stated simply. ‘Murder probably comes even easier to him.’