Chapter 65
Regarding the principles and knowledge of bombs, pure testing actually couldn't reveal much.
Anyway, Usuha Izuki could answer all the questions Hagiwara Kenji asked, solved all the problems he set, and Hagiwara Kenji even pulled out bomb models that Matsuda Jinpei had designed when bored for Usuha Izuki to defuse, which he also dismantled smoothly without any errors.
But Hagiwara Kenji's expression grew increasingly serious.
Because he vaguely realized something—Little Shinryu probably had exceptional talent in this area.
This level of testing couldn't measure the other party's true ability. He needed to try a different approach.
"...Little Shinryu." After pondering for a while, Hagiwara Kenji said, "Design a bomb. Don't worry about whether you can obtain the materials—as long as it follows principles, you can use anything. Don't hold back, let me see your level."
If the previous test measured mastery of fundamentals, then what he was testing now was how far the knowledge learned could be applied.
Some people, even if they understood bomb defusal principles, would have their thinking instantly limited to a few models when asked to design a bomb. It wasn't that they didn't study hard—they simply lacked talent in this area.
What Hagiwara Kenji needed to confirm now was precisely Samukawa Shinryu's talent in this field.
How could Usuha Izuki pass up such a good opportunity to farm suspicion values! Hagiwara Kenji was the one who said not to hold back!
So he took a blank sheet of paper and explained while drawing.
There wasn't much to discuss about the bomb casing—not many tricks could be played there. When designing bombs, most of the technology was in the control box—the part that triggered the explosion.
"—Use a metal shell for the exterior, with iron, insulating gel, and aluminum from outside to inside. If the person defusing tries to cut, the iron and aluminum will make contact, completing the circuit and causing an explosion."
"Install mechanisms under the screws like this, compressing spring contacts. If someone tries to disassemble from the screws, loosening just a quarter turn will extend the spring and complete the circuit... Pressure mechanisms are very useful and can be applied to several connecting positions to prevent violent prying of the shell."
"If it's for threats, you must prevent transfer to a safe area for detonation, so there must be a tilt detection device inside. A metal pendulum will do—PVC tubes with aluminum foil connecting two levels. Any tilting will trigger detonation..."
Hagiwara Kenji stared woodenly at the gradually taking shape design diagram.
After already preventing shell destruction, screw removal, control box prying, location transfer, and other methods, Samukawa Shinryu cautiously added water injection detonation, countdown detonation, switch detonation, decoy option detonation...
Almost as soon as a possible bomb defusal method appeared in Hagiwara Kenji's mind, Samukawa Shinryu immediately patched that method, turning the defusal action into a detonation trigger.
In the end, all the defusal methods he could think of had been anticipated and exploited by this design.
If the bomb's internal structure wasn't revealed in advance and the defuser relied on usual experience, the bomb would probably explode within a second of touching a screw.
Even using X-ray machines to scan the internal structure would only increase pressure due to the intricate design without helping defusal—at most eliminating some wrong answers. After elimination, besides surrendering to the criminal, the only option would be evacuating crowds and direct detonation.
So if this bomb were installed somewhere inconvenient for detonation, it would be virtually unsolvable.
Yet after finishing the design, Samukawa Shinryu's tone carried some regret: "This bomb isn't without flaws..."
Hagiwara Kenji was shocked: "What?"
Even like this, what are you still unsatisfied with?
"The volume is too large, and some mechanisms require on-site assembly. But for threats, the effect would indeed be good—just placing the structural diagram at the scene would let knowledgeable people know it's better to agree to my conditions."
Hagiwara Kenji: "............"
Little Shinryu, you don't need to get so into character saying "agree to my conditions"—I'll be tempted to handcuff you!
Though Hagiwara Kenji had indeed anticipated that Samukawa Shinryu should be very talented in this area, he hadn't expected a casual test to yield such terrifying results.
While this bomb had limitations in usage scenarios, once successfully installed, police would only be led around by whoever planted it.
Most terrifyingly, despite saying materials were unlimited, Samukawa Shinryu still used only the most basic materials.
He didn't choose more advanced alternatives with the same principles—the raw materials he selected were all obtainable by ordinary people, and it was purely mechanical structure. If he wanted, he could make one anytime—or rather, Samukawa Shinryu might have already planned to try making one, which was why he considered such details so thoroughly.
"Did that organization teach you this? Or is it your own design?" Hagiwara Kenji asked without hope, not even knowing what answer he hoped for.
Those deep red eyes seemed to see through his evasion: "The organization doesn't know about this design yet."
So it was his own conception.
Bombs were, in a way, also artworks from which the designer's thoughts could be glimpsed.
From this design, Hagiwara Kenji saw overwhelming meticulousness, caution, composure, and ruthlessness that used the most basic theories to design something leaving enemies no options except detonation and surrender.
...Little Shinryu indeed had great criminal talent.
But this didn't mean he would necessarily take a criminal path.
"Very good." After a moment of silence, Hagiwara Kenji took the design diagram and looked at it seriously again, even praising: "You've truly reached the pinnacle in bombs... I'm tempted to recommend you to Explosive Ordnance Disposal."
Knowing more than criminals—wouldn't that better prevent crime? Who said having criminal talent meant you had to commit crimes?
Samukawa Shinryu answered: "I'm not very interested in bombs. I'd rather go to the front lines."
"Mm." Hagiwara Kenji pretended to be calm as he folded up the design. "Perfect. Since the Mobile Investigation Unit just reorganized and needs people, you can go directly with Mobile Investigation during your internship. You definitely won't be assigned to a local police box after graduation anyway—you'll certainly be recommended to Metropolitan Police."
Samukawa Shinryu nodded.
"...You should try to hide your abilities there and not expose how capable you are." Hagiwara Kenji couldn't help bringing this up. "If you really encounter situations that are hard to refuse, definitely come tell me. Maybe two people can think of a solution."
"Alright, don't worry. As long as I don't want to do something, the organization won't force me for now."
Hagiwara Kenji sighed: "I hope you're not just saying that to comfort me..."
"It's true."
Hagiwara Kenji didn't believe it.
Someone like Little Shinryu was exactly the kind of talent illegal organizations would go crazy for. Having finally found a way to threaten him into joining, how could they not use it?!
Speaking of which, which organization was so brazen as to directly recruit from the Police Academy?!
Returning to Explosive Ordnance Disposal wouldn't give him access to this kind of information.
He really should become a detective.
Though Little Shinryu told him not to investigate, he'd never been an obedient personality. How could he do nothing knowing his friend was in danger?
After seeing off Samukawa Shinryu, Hagiwara Kenji routinely returned to the office to handle documents, had a normal dinner, and went back to his dormitory to rest.
At 2 AM, unable to sleep, he opened his eyes and painfully photographed the design diagram to send to Matsuda Jinpei.
[Little Jinpei, take a look at this bomb. What level is this?]
Matsuda Jinpei wasn't on duty tonight, but due to the day's events, he had nightmares at midnight—dreaming that there was no Samukawa Shinryu to catch the bomber, and the building where Hagiwara Kenji was located exploded before his eyes...
After waking from the nightmare, Matsuda Jinpei couldn't sleep at all. He simply got up to look at his phone and happened to see Hagiwara Kenji's email, so he casually opened it.
Due to network speed and phone model limitations of the era, the photo didn't load immediately—he only saw the text.
He and Hagiwara Kenji used to design bombs and give each other problems for fun, so initially Matsuda Jinpei didn't think much of it, just feeling somewhat annoyed—Hagi still had the mood to design bombs! He completely ignored what was said during the day!!!
But after the photo loaded, Matsuda Jinpei's attention was completely captured by the design diagram.
The resolution wasn't high and somewhat blurry, but he was indeed amazed.
Matsuda Jinpei was excited by what he saw and called Hagiwara Kenji directly: "What's the annotation on the left? Can't see clearly, and that line below..."
Hagiwara Kenji explained everything to Matsuda Jinpei, who became increasingly alarmed as he listened.
This thinking didn't seem like Hagi's.
Only then did he notice the handwriting was wrong: "...Wait, is this Samukawa's design?!"
"Uh..."
Not denying meant admitting.
Matsuda Jinpei stared at the design for a long time: "How did you teach this?"
Hagiwara Kenji deflected, still helping Samukawa Shinryu hide things: "I think at this level, it's no longer a matter of what can be taught."
"You're right. This is completely about natural talent." Matsuda Jinpei frowned. "This kind of bomb can only be detonated—it's a perfect bomb... Tsk, I wouldn't want to see this kind of bomb at a scene."
"Little Shinryu wouldn't do such things."
"You shouldn't have taught him in the first place! It's not like you can't be a police officer without knowing bomb defusal! Look how he dared to directly handle bombs as soon as he learned—what wouldn't he dare do!"
Matsuda Jinpei held his forehead: "He was already easily misunderstood, and today he almost got beaten by Mobile Investigation people because of the bomb defusal. If he'd just helped evacuate crowds like last time, this wouldn't have happened."
"What?" Hagiwara Kenji exclaimed. "He almost got beaten? By Mobile Investigation people? That's going too far..."
Matsuda Jinpei: "...Your priorities... Are you being too protective of Samukawa? He's not a child anymore!"
"But he's very worrying." Hagiwara Kenji sighed. "You don't know—the instructor has celebrated several times that I came as Assistant Instructor, otherwise his hair would all fall out."
"Even that old devil has such days..." Matsuda Jinpei absentmindedly responded, unable to resist looking at the design again and again, liking it more each time. "I want to make a model of this."
"No, how would you explain it if someone saw?" Hagiwara Kenji immediately said. "Delete this email right now."
"I'll say it's something an acquaintance heard about from the FBI—isn't it normal for America to have bomb criminals? Just pick a random case to attribute it to." Matsuda Jinpei began making excuses. "It would be good for training everyone too. Keep it internal and confidential. Anyway, this thing is so complex to install that even if people knew about it, they'd probably be reported during installation."
Hagiwara Kenji felt Matsuda Jinpei was getting a bit too excited now. He thought this reasoning wasn't great, but didn't want to directly dampen his enthusiasm, so he could only take a roundabout approach.
"...I'll ask Little Shinryu."