“I only need ten or fifteen minutes.”
“Can we talk while we walk?”
“Suits me.” Yukawa glanced around him. “But let’s talk here a moment first. Just two or three minutes will do. How about that bench over there?” He immediately headed toward the bench without waiting for Ishigami’s reply.
Ishigami sighed and followed his friend.
“We walked here once before together, didn’t we?” Yukawa recalled.
“That we did.”
“I remember you saying that the homeless people here had developed routines like clockwork. You remember that?”
“I do. That’s what happens when you take clocks out of people’s lives—I believe that’s what you said.”
Yukawa nodded, satisfied. “Too bad it’s impossible for you and me ever to be off the clock. Like it or not, we’re stuck in the cogs of society. Take them away, and our clocks spin out of control. Or rather, we are the cogs in the clockworks. No matter how much we might think we are off standing on our own, we’re not. It gives us a certain measure of security, to be sure, but it also means we’re not entirely free. I’ve heard that lots of the homeless don’t want to go back to living regular lives.”
“Keep chatting like this and you’ll use up your two or three minutes in no time,” Ishigami said, looking at his watch. “You’re at one minute already.”
“Okay—the world needs its cogs, all of them; and even a cog may say how it gets used. In fact, only a cog may determine its eventual meaning in the system. That’s what I wanted to tell you,” Yukawa said, staring Ishigami in the face. “Are you going to quit your teaching job?”
Ishigami’s eyes opened wide with surprise. “Why do you ask that?”
“I just thought you might be moving in that direction. You’re not planning on being the cog labeled ‘math teacher’ all your life, are you?” Yukawa stood. “Shall we?”
The two stood up and began walking along the Sumida. Ishigami didn’t speak, waiting for his old friend to say something.
“I heard Kusanagi paid you another visit. Checking on your alibi?”
“Yeah. Last week.”
“He suspects you.”
“Seems like it. Though I haven’t the foggiest clue why.”
Yukawa suddenly smiled. “To tell you the truth, he’s a little foggy on that as well. He’s only interested in you because he saw me taking an interest in you, that’s all. I’m sure it’s not my place to tell you this, but the police don’t have a bit of evidence to point them in your direction.”
Ishigami stopped. “So why are you telling me this?”
Yukawa stopped as well and turned toward him. “Because I’m your friend. No other reason but that.”
“Because you’re my friend you thought you needed to tell me about some murder investigation? Why? I have nothing to do with the crime. Why should I care if the police suspect me of anything?”
He heard Yukawa sigh—a long, slow sound. Then his friend shook his head. Something about the sadness in his expression made Ishigami feel nervous.
“The alibi’s immaterial,” Yukawa said quietly.
“Huh?”
“Kusanagi and company are obsessed with picking apart their suspect’s alibi. They think that if they keep prodding at the holes in Yasuko Hanaoka’s story, they’ll eventually find the truth, provided she really did kill her ex-husband. And they think that if you were her conspirator, then all they need to do is check out your alibi, too, and the fortress you’ve built will come crumbling down.”
“Sorry, but I haven’t the faintest idea what you’re talking about.” Ishigami frowned. “Besides, what’s wrong with detectives looking for holes in alibis? Isn’t that what they do? Assuming there really are holes to be found, that is.”
Yukawa’s mouth softened. “Kusanagi said something interesting the other day. He was talking about the way you designed the tests you give to your students, taking advantage of the blind spots created by the students’ own assumptions. Like making an algebra problem look like a geometry problem, for instance. It made sense. It’s very effective for tripping up the ones who don’t understand the underlying principles and just try to solve everything by the book. The student sees what they think is a geometry problem, so they attack it from that angle. But they can’t solve it. They get nowhere, and end up just wasting time. Some people might call it unfair, but it’s a very effective way of measuring someone’s true ability.”
“What are you getting at?”
“Kusanagi and company,” Yukawa said, his face growing serious, “think that this is a question of breaking down alibis. And why not, since their primary suspect has an alibi. Even better, her alibi feels weak. It feels like you could just keep hitting it and eventually it might break. The same thing happens all the time in our research, really. And, time and time again, we find that while we were happily swinging away at a problem, all the while we were completely off the mark. The police have fallen into that very trap. The bait was there and they took it, hook, line, and sinker.”
“If you have concerns about the direction their investigation is taking, shouldn’t you be talking to Detective Kusanagi, not me?”
“Yes, eventually, I’ll have to. But I wanted to talk to you first, for reasons I’ve just stated.”
“Because you’re my friend.”
“Yes. I might also say because I don’t want to lose your genius. I want to clear away all of this distraction and get you back to doing what you do best. You’ve got a precious brain and I don’t want it being wasted like this.”
“I don’t need you to tell me that. I already abhor wasted time,” Ishigami said. He turned away and began to walk again—not because he was worried about being late to his class, but because it had suddenly become too uncomfortable for him to continue standing in that spot.
Yukawa followed. “In order to solve this case, we mustn’t think that the suspect’s alibi is the problem. The problem lies elsewhere. A difference greater than that between geometry and algebra.”
“So, out of curiosity, what is the problem?” Ishigami asked without looking back.
“It’s not a simple thing, so it’s hard to give you a simple answer; but if I had to sum it up in one word, I’d say it’s a matter of camouflage. Subterfuge, even. The investigators have been fooled by the criminals’ camouflage. Everything they think is a clue isn’t. Every hint they uncover is merely a breadcrumb set in their path to lure them astray.”
“That sounds complicated.”
“Oh, it is. But if you simply change your way of looking at it, it becomes surprisingly simple. When an amateur attempts to conceal something, the more complex he makes his camouflage, the deeper the grave he digs for himself. But not so a genius. The genius does something far simpler, yet something no normal person would even dream of, the last thing a normal person would think of doing. And from this simplicity, immense complexity is created.”
“I thought you physicist types didn’t like talking in the abstract.”
“I can be more concrete, if you like. How are we doing on time?”
“I’m still good.”
“Still have time to drop by the lunch shop?”
Ishigami glanced at his friend before returning his gaze to the path ahead. “I don’t buy lunch there every day, you know.”
“Really? I heard you did. Well, almost every day.”
“Is that your smoking gun that links me to this case?”
“Yes and no. If you were simply buying your lunch at the same shop every day, that wouldn’t mean anything, but if you were going to meet a particular woman every day, that’s something no interested observer could overlook.”
Ishigami stopped and glared at Yukawa. “Do you think because we are old friends, you can just say whatever you like?”