Pathway to Japanese Literature

1

“Hmmph—”

After clearing his throat, Dr. Kido rose from his desk and strode over to Assistant Oka Kazuo’s seat.

“This is how it turned out—”

With that declaration, he tossed three curve diagrams onto Oka’s desk with a decisive swish.

……

Startled by the doctor’s sudden approach, Assistant Oka instinctively straightened his collar and stood up—or more accurately, nearly leapt from his chair.
After all, Oka Kazuo remained the newest member at this research institute.

“Look at these three diagrams—Figure 1, Figure 2, and Figure 3.”
“Everything is clear beyond any need for clarification—indisputably clear.”

Dr. Kido neatly arranged the three curve diagrams labeled Fig. 1, Fig. 2, and Fig. 3 in English in a straight row.

“Uh—”

Assistant Oka, unable to muster an immediate reply, sent his gaze flashing down onto the diagrams like summer lightning.

*Since the measurer was listed as Kido, this had to be something the professor measured.*
*The curves formed mountain-like shapes—Figures 1 and 2 resembled Mount Fuji.*
*Only Figure 3 showed two peaks, like an enlarged version of Futamiura’s Wedded Rocks.*
*What could this possibly mean?*

Assistant Oka compared the three diagrams and tilted his head slightly.

“Crystal clear, wouldn’t you say…”

And Dr. Kido remained alone, overwhelmed by emotion.

“Uh— uh—”

(If I don’t grasp the meaning of these three curves quickly, I’d be failing him—truly failing him.) Assistant Oka strained to comprehend, burning the three curves into his retina through sheer force of focus.
(The suspects Urayama, Isoya, and Inuzuka—so this must relate to the three suspects.
The three suspects and... Hmm...)

“Hmm,” he blurted out involuntarily,

(That’s it.
It might be about the suspects from that case.) he finally recalled.

That incident—what was it?

Regarding that incident, the narrator next wished to provide a brief introduction.

2

This is a story from Manchuria, far to the north.

If you open a map and look, you will see that the East Branch Railway crosses Heilongjiang Province.

Upon closer inspection，one would see that this East Branch Railway cuts cleanly through the Great Khingan Range．
The location lay between Baktu Station and Xing’an Station．
To elaborate further，between these two stations lay a massive tunnel named the Xing’anling Tunnel，measuring three kilometers—nearly thirty chō—in length，which cut cleanly through the Xing’anling Range．
That incident indeed occurred inside this tunnel．

Now, the morning of the incident—though now somewhat old news—was a certain day in August last summer.
At precisely 7:00 a.m., the train in question departed Baktu Station, heading toward Xing'an Station.
It had been a long overnight journey, and the compartment was filled with stifling tobacco smoke, the foul breath of gluttonous passengers, and—how to put it—the musky stench of young travelers who had gone too long without female company, making for a truly unbearable night that left one choking back gag reflexes.
With the unmistakable arrival of dawn, the foulness escaped through the window that had been clattered open with a hiss, and in its place, fresh air—served in the vessel of a fresh morning and offered to all—brought a sense of relief as if we’d been revived.
Especially after the train departed Baktu, the view outside the windows revealed groves of white birch trees stretching tall and straight, their beauty on full display. Both passengers and crew had by now forgotten all else, greedily drawing the morning air into their lungs as if devouring it.

“I wonder which is whiter—the trunks of those white birch trees or women’s thighs, Ah.”

“Yeah.”
“Bwahahah!”

“Bwahahah!”

Should it be said they feared not even God? After all, this was the interior of a train racing through the remote hinterlands. Even if a group spouting such indecent words had commandeered an entire train car, there was hardly any reason to be surprised.

This group was a band of forty members who had come en masse under the guise of a development and migration group, but they were in fact a gang concealing nefarious purposes behind this noble pretext.
They differed from those greenhorn gangs that would rob banks for meager sums only to get arrested shortly thereafter—this was a highly disciplined and rigorously trained organization, what might be termed a full-fledged organized crime syndicate.
Sworn to neither faction nor creed, the group charged forward under Boss “Iwa’s” command, advancing however their leader’s fleeting whims dictated.

However, this “Iwa”—Iwaoka Iwakurou—was no mere “windblown gangster”; through his fearsome skills, he had been threatening certain powerful figures and operating quite openly and brazenly.
This becomes plausible when considering how this nefarious group boldly advanced through Manchuria in a chartered train, slipping through the tight mesh of authorities’ strict surveillance.—Though I had promised to keep my account brief, explaining the “Iwa” gang has proven quite laborious.

Now, the train carrying this group had somehow managed to navigate through twenty-seven bends winding through a beautiful birch forest,

“Wooooo”

With a blast of its whistle, it dove into the Xing’anling Tunnel—the very one said to measure thirty *chō* (approximately three kilometers) in length.

Instantly, a terrible reverberation roared through the tunnel’s interior.
The bright interior light abruptly dimmed, and darkness surged forth like black ink gushing out.

“Ah.”

Someone shouted in a low voice.

“Ah, the lights aren’t on…”

Another voice groaned.

The light streaked away like an arrow.
The faint afterglow had cut out a square shape from the window frame, but even that faded as if being absorbed by blotting paper.
And finally arrived an absolute darkness like black ink.
The demon called absolute darkness kept pressing and expanding the compartment’s space with terrifying force.

The resounding roar of wheels madly dancing across the rails flowed through the passengers’ ears—through that sensation alone, they barely recognized they were alive.

However, to be precise, there had been one passenger who could no longer recognize their own existence during this interval.

“Ugh.”

A considerable number of people had heard that low groan.

Ha—.

Before anyone could process the thought, there came a clang like the strike of a thick iron plate, followed by an unsettling vibration—a sensation that could only be described as an earthquake receding into the distance—which clatter-clatter-clattered away into the far reaches.

By the time the train had suddenly emerged into the bright world beyond the tunnel, the forty group members had somehow become thirty-nine.

Bang, bang, bang.

The door near the locomotive clattered violently, and when it finally swung open with a crash, a conductor with a bright red face rushed in, pistol in hand.

“Wh-wh-who was it?!”
“The one holding the door from the inside was….”
“Tch tch. Outrageous!”

The senior conductor—a six-shaku-tall (approximately 180 cm), sumo wrestler-like figure—was steaming with anger.

The gang members, like demons masquerading as princesses, put on prim airs, turned away, and feigned ignorance.

“The rear conductor reported an incident in the tunnel, but now I can’t even get there, can I?!”
“If this were a major incident…”

“Hey, over here!” At that moment, the rear conductor called out from the window of the rear car’s compartment.

The front conductor hurried through the car compartment and rushed to where the rear conductor stood.

“Look at that!”

The rear conductor—his face deathly pale—indicated something with the trembling muzzle of his gripped pistol.

“Whoa! They did it!”

The front conductor’s face too turned instantly ashen.

Between the train cars—whether on the steel bodywork or the couplers—bright red blood splatters clung thickly, with droplets pattering down below.
The fallen bright red spots raced backward as if flying along with the rails.

Accident?
Intentional?

The two armed conductors stealthily drew close, whispered into each other’s ears, and nodded emphatically in agreement.
Then, after splitting up to both sides, they put on innocent faces and took up positions blocking both exits of the chartered compartment.

From headquarters, a telegram had already arrived for this train instructing them to be on guard against the gang in question; coupled with the fact that upon entering the tunnel, the lights had strangely failed to come on—and now this tragedy occurring there—with all this, the conductors’ necessary course of action was perfectly clear.

Sure enough, even before the train had fully arrived at Xing’an Station, a squad of security forces had already clamorously stormed into the carriages and promptly restrained everyone’s freedom.

3

Xing’anling Tunnel Murder Case!

Assistant Oka re-examined Figures 1, 2, and 3 once again.

“Heh—”

Dr. Kido cleared his throat and—bringing his desiccated, lackluster fingertip close to Fig. 1—then declared:

“Excitation Curves—that’s what I call my research.”
“How are these curves plotted?”
“That has already been made clear in what I had published in the September 1930 issue of the Z.F.P. Journal, page 30.”
“In short, all of this can be plotted using that recording device there in the corner.”
“Broadly speaking, human beings are like oscillators of excitation—always burning their nerves on some stimulation or another twenty-four hours a day.”
“When one grows hungry, an appetite arises, and they become excited—craving beef sukiyaki or wanting to devour a tempura rice bowl.”
“When night falls, the day’s mental stimuli precipitate like dregs, and this brings about the excitation known as dreams.”
“A human being without excitation is an exceedingly rare thing.”

“Since excitation is a neurological phenomenon, it can be considered a type of electrical occurrence,”
“And since it is an electrical phenomenon, its strength can be measured.”
“Strong excitation causes the meter’s needle to swing widely, while weak excitation only moves it slightly.”
“Now then, you see—”
“As I previously published in the Z.F.P. Journal, you see, I succeeded in analyzing excitation by its types.”
“This was, after all, no mere matter of one or two attempts at effort…”

Thereupon, Dr. Kido closed his eyes fixedly, as though recalling the hardships of his research at the time, and for a while kept his hand resting upon his forehead.

“It was truly a painstaking endeavor, you see.”
“However, to state the result, it is supremely straightforward.”
“Differentiating types of excitation is precisely the same as turning the dial on a radio receiver—depending on where you set the scale, different broadcast stations come through accordingly, you see.”
“When Tokyo’s First Broadcast is coming through, if you turn the dial slightly, Hiroshima FK’s broadcast appears.”
“Turn it further, and broadcasts like Sapporo IK, Nagoya CK, Niigata QK, Kumamoto GK, Shizuoka PK, Sendai HK—twenty-seven different stations—come through with just one twist of the dial.”

By merely installing a similar mechanism within the aforementioned device, one could not only differentiate between types of excitation but also discern their varying intensities.
“It’s the same as when you turn a radio’s dial to listen to different stations—Tokyo’s First Broadcast comes in strong, Hiroshima’s is very weak, Sapporo’s can’t be picked up at all, Nagoya’s next one isn’t as strong as Tokyo’s First but still quite clear… You can compare their strengths in that manner.”
“In other words, excitation A has a strength of 2, excitation B a strength of 5, excitation C a strength of 10, excitation D a strength of 7—in this manner, their intensities manifest on the meter.”
“When that is plotted on a graph, it forms a curve like Fig. 1.”
“Do you follow—”

Dr. Kido—producing a pencil as if by magic from nowhere—smoothly wrote down numbers along the edge of the diagram.

“First, A is 2.”
“Then, on the horizontal axis labeled ‘Type of Excitation,’ a point marked X is plotted at position A on this axis and at the height corresponding to the number 2 on the vertical axis indicating intensity.”
“Next, on the adjacent B, take the height of 5 representing excitation strength and mark an X.”
“Then on C—at the height of 10 representing the strongest intensity—mark an X. The points obtained through this method are numerous; connecting them horizontally with lines results in a curve like this Fig. 1.”
“At a single glance of this curve, the excitations residing within that person become as vividly clear as if held in one’s hand.”
“Thus, using the same method, I was able to plot excitation curves for the subsequent Figures 2 and 3 as well, you see.”

The meaning of these three precious curves—signed "Measurer: Kido"—had finally begun to be dimly comprehended within Assistant Oka Kazuo's mind. However—what kinds of excitations did types A, B, and C themselves indicate? Who exactly were the suspects Urayama, Isoya, and Inuzuka?

4

“Dr. Kido,” Assistant Oka called out.

“Heh—” Dr. Kido responded with a cough—though from its tone, one could discern he was irritated at having his lecture interrupted.

“Dr. Kido.
“Dr. Kido. Would this be related to the aforementioned Xing’anling Murder Case?”

“……”
Dr. Kido remained silent for a moment, his mouth working restlessly—a mannerism that could only signify “Yes” from this doctor renowned for his eccentricity.
“And so, regarding the thirty-nine individuals who shared that train car—I took these Excitation Curves of theirs, but…”
Dr. Kido’s explanation abruptly veered into experimental methodology.

For Dr. Kido, this was only natural.
Dr. Kido Nobuyuki was none other than a serious scholar; therefore, being neither a Sherlock Holmes, a Philo Vance, nor a Homura Sōroku, he had no inclination to discuss the ongoing details of the case.

This is where the author will provide a brief explanation.

Forty minus one equals thirty-nine—and thus suspicion of murder fell upon the remaining thirty-nine people.
That this was murder rather than suicide became evident from the purple bruising found in the throat area of the mangled corpse later discovered within the tunnel.
Strangulation—meaning they had constricted his throat.
Then they threw the corpse out of the window.
Though called a corpse, this still-warm body had no sooner fallen onto the rails from between the cars than they finished it off with a sickening crunch.
Blood bursting forth from the wheels and undercarriage dyed the entire surroundings crimson.

Now, under normal circumstances, this would not have become a major issue—it would have been treated as a routine criminal matter and settled once some suitable person came forward as the culprit and was executed.
But in this case alone, there were exceedingly troublesome circumstances.
The victim was a man named Shiina Sakimatsu—known as "Matsu"—who, while posing as a member of the group, had in fact been serving as an undercover agent for the relevant authorities.
The killing of Shiina Sakimatsu was perceived as a challenge to the authorities.
The case suddenly took on an increasingly complex turn of events, and for the authorities, readily accepting and executing the fabricated culprit that had emerged there would have been utterly undesirable in terms of maintaining their gang’s authority.
They absolutely needed to identify and execute the true culprit to suppress the long-festering cancer that was their gang’s overbearing dominance.

However, when it came to investigating traces of the crime, the officers found themselves compelled into perplexity.
The reason lay in all thirty-nine individuals who had ridden together belonging to the same faction; under Boss Iwa’s orders they coordinated communications and resolutely refused to utter any inconvenient truths.
Yet this was not all.
After all, this was an incident within an utterly lightless tunnel.
There existed no tangible matter requiring investigation.
For during those five minutes encompassing the crime’s occurrence and aftermath—complete darkness reigned.
Dispatching skilled investigators from Japan proper at this juncture likewise proved futile.
With evidence being vanishingly sparse and thirty-nine men versed in villainy conspiring toward its obliteration—to seek discovery verged on impossibility.

With all measures exhausted, they had no choice but to call upon Dr. Kido to take charge.
Dr. Kido himself did not possess overwhelming confidence, but after deliberation he made some modifications to his research apparatus and resolved to proceed with the investigation.
Thus excitation curves were taken for the thirty-nine surviving gang members.
From the thirty-nine curves, the three that Dr. Kido ultimately extracted were those obtained from Urayama Eijiro, Isoya Kyosuke, and Inuzuka Hyokichi.
The three were still confined in Dr. Kido’s laboratory.
The other thirty-six individuals were released; some departed again for Manchuria, while others abandoned their efforts and turned their steps elsewhere.

“...Among them, what captured my attention were those of these three suspects: Urayama, Isoya, and Inuzuka.”

Thus Dr. Kido explained.

“To begin with, while I can distinguish between types of excitation curves—A, B, C, et cetera—it’s not as though every letter corresponds to clearly defined excitations.”
“I’m still researching this matter—it remains incomplete.”
“Yet it suffices perfectly for resolving our current problem.”
“You see, this C-excitation pertains to categories like hatred or jealousy—only these three exhibit it so markedly.”
“As murder motives go, one cannot act without sufficient excitation of hatred or jealousy—that’s fundamental.”
“We found C-excitation present solely in these three.”
“Should murder occur in past, present or future—it must come from among them.”

“Now then—Fig.1 and Fig.2 for suspects Urayama and Isoya are passable for now.”
“What demands attention is Fig.3 of suspect Inuzuka.”
“This shows what should be termed F-excitation with extraordinary prominence, does it not?”
“As for what this F-excitation signifies—according to my research findings, it indeed represents murderous excitation!”

“Then does this mean Inuzuka is the murderer?”

Assistant Oka exclaimed in astonishment at the strikingly clear result.

“That’s right—Inuzuka Hyokichi strangled Shiina Sakimatsu and threw him from the train.”

“Ah, even so…”
Assistant Oka had profoundly felt the joy of being admitted to Dr. Kido’s mentorship.
“This detestably towering murder excitation curve?”

“If one examines this, no villain—however cunning—can fully conceal their crime.”

“Dr. Kido. What if we promptly mass-produce this device and distribute it to all courts and police stations nationwide? By abolishing wasteful interrogations and immediately revealing the facts, I believe this would constitute a monumental reform for the judiciary.”

“But however—”
“Hm-hm,” Dr. Kido shook his head from side to side.
“Taking these excitation curves requires great skill.”
“Even you, who graduated from graduate school, shouldn’t be able to take them this skillfully.”

5

For Assistant Oka Kazuo, who had received the Bachelor of Science degree and completed three years of graduate research, the remark Dr. Kido had made—however much he revered Dr. Kido—was not something he could let pass.
Thereupon, he earnestly pleaded with Dr. Kido and requested permission to use the device to measure excitation curves from the suspect.

“Very well, you may attempt it.”

Dr. Kido finally relented and granted Assistant Oka’s request.

Assistant Oka pulled Inuzuka out from the detention room and placed him on the platform in the laboratory.
And after moving the device close to his body, he manipulated the complex switches, resistors, and dials to observe numerical values for producing excitation curves.

And the curve he finally completed was the one shown in Figure 4.
He did not forget to enter "Oka" in bold strokes in the measurer field.

“Hmm...” Dr. Kido lined up the submitted Fig. 4 with Fig. 3—which he had previously created for the same Inuzuka—and uttered a peculiar sound.

Whether he was being laughed at or praised remained entirely unclear to Assistant Oka for a short while.

“This is rather remarkable,” declared Dr. Kido as he removed his pince-nez.
“The C-excitation and F-excitation are distinctly evident.”

“Ha ha...”
Assistant Oka was initially relieved.

“But now,” declared Dr. Kido as he tapped Oka’s curve diagram with his pince-nez. “You’re still too green for real-world application. Look here—take C-excitation, for example. In my results as well, while this Inuzuka has the lowest among the three, it nevertheless exceeds 8. However, yours is only about 5.5. The crucial F-excitation is also appearing absurdly severe. At first glance, the shape of the curves also differs considerably from mine, doesn’t it? This is the difference between skill and lack thereof.”

“You are absolutely correct,” Assistant Oka replied humbly.

“And then, look at this spot here,” Dr. Kido said, pointing to the K-excitation section of the third diagram.
“Although not prominent there, K-excitation is present.”
“Yours is as flat as a man’s chest—there is nothing showing here at all.”

Indeed, in Dr. Kido’s measurements—from Figures 1 to 3—there was a slight elevation there, but in Assistant Oka’s, there was none.
He believed he did considerable work, but it simply wouldn’t appear.

“I am deeply grateful.”
Thoroughly humbled, Oka dipped his head there.

6

Then two months flowed by.

That day, Assistant Oka had been scheduled to attend the university in the morning. He went to Classroom 28 as usual and lectured on “The Theory of Electrical Oscillations in Brain Tissue” before fourteen or fifteen science students.

At that moment, the entrance door clacked open, and Kimitada—the janitor reputed never to have been seen smiling—entered. Without a word, he approached the lectern, placed a single scrap of paper upon it, then exited through the same doorway wearing an expression as though nothing had transpired.

*(What could this be?)*

Professor Oka—at least within this classroom at this moment—stopped midway through writing equations across the blackboard and looked at the paper scrap on the desk.
There lay a penciled note dashed off as follows.

“Since Dr. Kido has been phoning incessantly, I’m briefly relaying this during class hours.”
“He says: ‘Stop dilly-dallying with that university lecture and get back here at once—or I’ll have your head.’”
“Matsushita Sei”

Matsushita was the name of an assistant professor who had graduated a year before Oka.

From this, it seemed some urgent matter had arisen.
He couldn’t very well announce his departure by saying, “I’ve been told by you students to ‘quit dawdling with this lecture,’” so instead he cited urgent business and ended the class.

Assistant Oka, who had hailed a car and hurried back to Dr. Kido’s laboratory, was startled upon entering the room to find the doctor in an altered state.
That usually composed Dr. Kido was pacing around the room like a lion trapped in a cage.
Naturally, it appeared he hadn’t noticed Assistant Oka’s arrival.

“Dr. Kido.
“I’ve returned,” Oka called out.

“Oh, Mr. Oka!”
Dr. Kido turned eyes glittering with excitement toward his assistant and shouted.
“No—this is a monumental discovery!”
“I have bestowed upon it the designation ‘Kido phenomenon.’”
“I intend to promptly announce this to our academic community while simultaneously dispatching the manuscript to four nations’ scholarly associations: Britain, America, Germany, and France.”
“Mr. Oka, I require you to initiate the translation immediately.”

Assistant Oka momentarily wondered if Dr. Kido had become deranged.
However, the circumstances gradually became clear.

“...And so, I have succeeded in extracting the K-curve from the excitation curves.”
“Look at this.”

With that, Dr. Kido placed Figure 5—labeled “Fig. 5”—before Assistant Oka, almost as if tearing it from his desk.
When he looked at the diagram, this was completely different from previous curve diagrams.
It was a curve with a slight bulge at the K-excitation section, deliberately inscribed with “the foundational curve that led to the derivation of the Kido phenomenon.”

“This is what I would call the K-excitation curve.”
“This is something I had long questioned—these recognizable bulges are also present in the excitation curves of the three suspects: Urayama, Isoya, and the true culprit, Inuzuka.”
“The strength is nearly uniform.”
“When we eliminate other prominent excitations, it ultimately becomes this Fig. 5.”
“What do you think this K-excitation common to these three signifies?”
“Answer me.”

Dr. Kido glared fixedly at Assistant Oka from straight ahead and spoke.

“Well, I’m afraid I don’t know.”

“You don’t understand?”
“Then I’ll tell you.”
“This is abnormal excitation.”
“It’s an excitation that indicates a predisposition toward mental abnormality.”
“And this abnormal excitation isn’t limited to just those three individuals, you know.”
“In the curves measured for the remaining thirty-six individuals involved in the Xing’anling Tunnel Murder Case, it has also manifested itself incrementally.”
“In most of the other cases I measured as well, bulges of K-excitation have manifested.”
“In short, the conclusion is as follows.”
“‘All humans, without exception, possess a predisposition to mental abnormality.’”
“Isn’t this a splendid discovery?”

“Are there no exceptions?”
“In other words, humans without that K-excitation are…”

“They do exist.”
“However, in all my recent measurements, there has been K-excitation.”
“The exceptions where it’s absent only appear sporadically among measurements taken long ago, and I don’t consider that an issue.”
“In short, every human possesses the predisposition to develop mental abnormalities!”
“How terrifying this is!”
“Mr. Oka.”

“It’s truly dreadful.”

When he averted his eyes from the unsettling Figure 5, Oka abruptly stood up and walked toward the bookshelf lined with dictionaries to use for translation.

7

The Kido phenomenon!

The fame of Dr. Kido, who discovered it, blazed forth like the sun illuminating the academic world.
And indeed, this was only natural: given that Dr. Kido—who a year prior had succeeded in measuring excitation curves across individual human bodies—had within a brief period further succeeded in breaking down these curves, extracted abnormal excitation curves, and moreover identified a universally latent predisposition toward abnormality in humans, dubbing this the Kido phenomenon, none could help being astounded.
Now, the academic discipline that might be termed Dr. Kido’s psychophysics—positioned as something holding the key to humanity’s developmental future—abruptly became the focal point of intense scrutiny within scholarly circles.

However, suddenly—utterly suddenly—Dr. Kido Nobuyuki, discoverer of the Kido phenomenon, had gone missing.

『Dr. Kido’s Disappearance Throws World Academia into Great Panic!』
“Dr. Kido: No Clue Found Even Five Days After Disappearance!”

“By Whose Hand Was Dr. Kido Abducted?”
“The Kido Phenomenon and Excitation Curves’ Twisted Fate!”

“Reward: 1,000,000 Yen.”
“Will be given to whoever safely returns Dr. Kido to his residence!”

Such were the reports with which newspapers and radio were abuzz regarding the doctor’s disappearance.

But for some reason, no word of Dr. Kido’s whereabouts was ever heard.

And one day, the Investigation Division Chief of the Metropolitan Police Department visited Assistant Oka, who was keeping watch at Dr. Kido’s laboratory.
Oka Kazuo was diligently moving his pen across the academic thesis spread out on his desk when, upon noticing the Chief’s presence, he stopped writing and called out cheerfully.

“Oh, welcome, Mr. Ooeyama.”

Ooeyama was the surname of the Investigation Division Chief.

“I’m afraid I’ve come to trouble you again.”
Inspector Ooeyama said sheepishly.
“Today being the agreed thirteenth day as well...”

“I haven’t forgotten either. But what became of the Metropolitan Police Department’s prospects?”

“When you ask me that, it makes me terribly gloomy,” Inspector Ooeyama said as he smoothly stroked his balding forehead. “We established our investigative policy under the assumption that the gang from before had disposed of Dr. Kido because he became a hindrance.”

“So—”

“However, no matter how much we tried, it was completely futile.”
“The more we investigated, the more evidence surfaced that was unrelated to their gang, and we were truly stumped.”
“This time of all times, I tell you.”

“So…”

“So… That’s a rather pointed question.”
“Under these circumstances, there remains no path but to humbly heed your theory.”

“Is that so,” Assistant Oka nodded deeply.
“Then let us forget our past disagreements, and I shall present my theory.”

Having said that, Oka collected a large number of curve charts from the desk.

“Another set of curve charts?”

The Inspector forced a laugh.

“It all comes down to these curve charts—through and through,” Assistant Oka said with a sly grin. “Now please take a look. These are Dr. Kido’s renowned curve charts documenting the Kido phenomenon.”

With that, he placed the already familiar Figure 5 before the Inspector, retrieved another chart labeled Figure 6, and aligned both diagrams side by side.
On the latter was clearly affixed a signature reading "Measurer·Oka".

“The one labeled Fig. 6, which we’ve laid out side by side, is actually the conclusion of my research,” he said. “I would like to eliminate Figure 5, which represents the Kido phenomenon, and instead recommend this one to all of you.”

“What did you say?”
The Inspector’s eyes widened in astonishment.

“There’s no curve on this one, don’t you see?”

“It does exist.
“Look—” said Oka, pointing to a curve that lay extremely close to the diagram’s horizontal axis—virtually flat, so faint it was unclear whether it held any significance as a force.
“This barely-there curve—in radio terms, it’s not a broadcast but akin to static, something that truly signifies nothing at all.”

“Hmm—”
The Inspector had the look of someone utterly bewildered.

“To put it another way, the Kido phenomenon states, ‘Every human being without exception possesses the predisposition for mental abnormality.’”
“Mine is the opposite conclusion: ‘One cannot say that every human being has a predisposition for mental abnormality.’”

“Are you saying there’s no predisposition for mental abnormality?”
“That’s somewhat reassuring.”
“However, Dr. Kido’s curves clearly showed K-excitation taken from numerous people.”
“With all due respect, isn’t the error in your measurements?”

“Your doubt is quite reasonable,” Oka said with a grin. “However, there is a basis for this. The truth is, I harbored certain doubts regarding Dr. Kido’s measurements, and just recently—under the supervision of Professor Satomi Ken, the university’s head of science—I retook the excitation curves for those three suspects.”

“Ah, the renowned Professor Satomi Ken?”

“That’s correct.”
“Professor Satomi Ken.”
“However, the results turned out differently from Dr. Kido’s—exactly as anticipated.”
“This is it.”
“They are Figures 7, 8, and 9.”
“Let us line up and examine Figures 1, 2, and 3—those measured by Dr. Kido.”
“What do you think?”
“In Dr. Kido’s data, K-excitation of identical form appears in every curve—yet in my measurements, not a single instance manifests.”
“They all resemble a man’s chest—Dr. Kido once described them thus—but here, the excitation peaks are utterly flat.”
“These are the true curves.”
“That matters would reach this point… Well—long ago when I first joined the laboratory—though rather awkwardly executed—when I produced what was termed Figure 4… this flat result emerged… planting within me a slight suspicion.”
“Through subsequent research… my conviction only deepened.”

“Then what becomes of the K-excitation appearing in Dr. Kido’s Kido phenomenon? And does that have some relation to Dr. Kido’s disappearance?”

“It’s truly regrettable,” Oka said, his face clouding over. “Dr. Kido had a latent predisposition for mental abnormality. He likely failed to notice it himself. The abnormal excitation of Dr. Kido—the measurer—had contaminated all experimental results he measured. It had been misinterpreted as though the measured subjects possessed mental abnormality predispositions.”

“This isn’t entirely unprecedented—similar cases exist elsewhere. Take the ‘body effect,’ for instance—when measurers position themselves too close to devices, electricity that should discharge into the earth instead flows through their bodies, creating misinterpretations.”

“The abnormal predisposition concealed within Dr. Kido’s physiology introduced errors into excitation curves. The so-called ‘Kido phenomenon’ was fundamentally flawed. We propose renaming this error contamination effect as the ‘Kido Effect’ moving forward.”

“That K-excitation curve in Figure 5 merely represents Dr. Kido unwittingly exposing himself to this ‘Kido Effect.’”

With that, Oka Kazuo fell silent.

"So now, Dr. Kido is…"

Inspector Ooeyama gave voice to it.

“That’s correct.”
“Dr. Kido must have ultimately succumbed to illness as his tragic fate dictated.”
“As for the motive, I believe that the abnormal predisposition lying dormant within him—stimulated by the immense excitement of having discovered what was then called the Kido phenomenon, the Kido Effect—suddenly erupted.”

Oka Kazuo no longer had the courage to speak further of the pitiable Dr. Kido.