Monogatari Series - Volume 25 - Chapter 4.07

007 

The epilogue, or maybe, the punch line of this story. 

Though I’d been completely deceived by the name of the “Pretty Boy Detective Club”, the earth-shattering gender-reversal-type narrative trick had finally been revealed, so let us resolve the remaining mystery—namely, the mystery regarding the piranhas that Mayumi-kun, who was actually Mayumi-chan, had witnessed. Of course, it wasn’t like I had any specialized knowledge pertaining to “that”, so allow me to tell you in advance that the following explanation has been woven together with information that was taught to me the following day by the brains of our group, Hanekawa Tsubasa. 

Stereopsis. 

To be more precise, it had to do with random dot stereograms— referring to pictures that were constructed as clusters of dots that looked like random noise at first glance, but when you focused on a specific point or intentionally changed up your sense of distance, some sort of design would appear. 

Compared to 3D and even 4D effects appearing in the movie world, something like this seemed rather analog, but considering that you would be able to see these three-dimensional objects without the use of special glasses, these stereograms were still pretty revolutionary. 

Of course, because of how they were constructed, it was difficult to make complicated designs into three-dimensional shapes—only simple constructions like letters or cubes, cups or dice, balls or pencils… As well as simplified animals or plants. 

And fish. 

In a way, it was a kind of “visualization” similar to how you could connect the stars in the sky to imagine constellations—when Mayumi-chan had gotten a sweeping view of the town on top of the shrine, she’d seen that “visualization”. 

And she’d seen that same fish when she looked at the town map. 

Thinking it through, it was perhaps just a simple matter of coincidence, and although it may not be something that anyone would be able to see, it was possible that someone would have been able to see those piranhas even if they didn’t have the special eyesight that Mayumi-chan had—being just one of the functions of humans’ eyes. 

The function of grasping a sense of distance. 

If the bird’s-eye view of the town had ended up forming some kind of random dot stereogram. 

The roads were generally set up to be straight, and most buildings, when seen from above, took on rectangular shapes—looking at it all from a distance, it could easily appear as a dot pattern of random noise. 

In the first place, it was unlikely that a person would look down at a town from above, and even if they were looking at a town map, they probably wouldn’t process the information on that map as a single picture. If anything, they’d probably see it from an oblique angle, looking at it part by part. 

However, in Mayumi-chan’s case, it wasn’t just that her eyes were simply good, but also that she had a brain that was capable of processing that information—capable of, say, unconsciously calculating the refractive index of starlight through clouds and then automatically adjusting for it. Therefore, even if it was the sweeping view of a town seen from an oblique angle, she could reconstruct the information transmitted from her optic nerves and reinterpret it in many different ways. 

The ability of spatial awareness, or perhaps the eyesight of spatial awareness—as a result, she was able to get an image of the town as if she’d looked down at it from a bird’s-eye view. 

And had generated a fish above the town via stereopsis. 

She’d instantiated it. 

When you managed to see the image for just a moment, it ended up being hard to shake it off—it left a strong afterimage in your retinas, so it was like it would never go away. 

Since the town map was just a close-up view and not a strict recreation of the town, it seemed hard to say that it formed the same random dot stereogram on its own, but it had simply been enough to remind Mayumi-chan of the bird’s-eye view that was already in her brain. 

Well, it wasn’t really my place to say this, but she seemed like a kid who strongly stuck to her impressions, so after she saw something once, she probably had the tendency of continuing to see it—the reason she called the fish she’d seen neither a whale nor a dolphin nor a sunfish but specifically a piranha could have been because of her preconception of piranhas having jagged teeth. 

After all, the construction of the town had most likely only become like a stereogram by chance, and it was unlikely that a person with the expertise needed for something like this did it during the city planning phase just for fun, so the actual design that would appear was probably very distorted—and due to that distortion, it was possible that people would see not the image of a piranha, and instead something like a deep-sea fish. Just like a Rorschach test, there were probably people that saw something completely different. 

If it were me. 

I would probably see an oni. 

Knowing this much, it was pretty obvious why she stopped seeing it when rain began to fall—obvious, or perhaps a blank space.  

It was because there was a blank space in the sky that there was room for the piranha to float around. 

But if the falling raindrops continuously filled up that blank space, then she’d end up focusing on that, and there would literally be no more room for the piranha to appear—the visibility of her imagination had been painted over by the visibility of reality. 

The amount of information exceeded her limits. 

You could perhaps say that, even if her eyesight had no limits, the amount of information her brain could process did have limits—in that case, it was really dependent on how Mayumi-chan’s brain decided to interpret what she saw, but at any rate, as a result, it meant that the piranha that Beautiful Sight Mayumi saw above the town and in front of the map was not an oddity at all. 

As long as this town didn’t use to be a river or a lake or a swamp in the past, it had no connections to fish in the slightest, and there was no way that that held any connections to the Kitashirahebi Shrine, either. That would just be too good to be true. 

It was not an oddity, but having said that, it wasn’t just a trick of the light or one’s imagination, either. 

Not a trick of the light, but an optical illusion. 

Not one’s imagination, but one’s functionality.  

However, if we say that, if we understand all that, then there was no longer any need to fear the piranha—there was no need to close our eyes to it. In fact, it could even serve as a fun attraction to enjoy. 

Mayumi-chan and I, unable to see even an inch ahead of us in the rain, ended up walking back into town as if taking an underwater stroll, and I had succeeded in sending, not him, but her to the nearest station. 

“Oh, there’s no need for you to thank me like that. I only did what anyone would’ve done.” 

“Um, I didn’t even thank you yet… Although I was hesitating over whether I was even going to. But, yes, you have my thanks. Even if I… Even if I  had been on my own, and the piranha disappeared when it began to rain, I think I would have been too scared to go down the mountain.” 

“Nah, I don’t think so. Since you aren’t alone at all. But really, I wonder where your glasses went. I’ll go back and look for them just in case… But I wonder if there’s actually a black hole at that shrine. Will you be fine on your own from here?” 

“Yes. There’s no trouble at all from here. Sorry for bothering you… Even though you did what anyone would’ve done, I’m still glad. That you snuggled up close to me, and that you believed what I saw as if it was natural. My leader would probably say something like this. ‘It’s outrageous to say that you only did what anyone would’ve done. What you did was absolutely beautiful.’” 

“What a cool-sounding leader… Or rather, you could say it’s beautiful. Your leader, huh? I’d like to meet that leader someday.” 

“Ahaha… Of course, I’m sure you’ll have the chance to, someday. Because Leader might be as much of a weirdo as you are.” 

I’d assumed that those words said with that meaningful smile were just said for politeness’s sake as she was about to depart, but apparently, it turned out to be Beautiful Sight Mayumi’s prediction. 

About half a year later, I would end up meeting the extraordinary pretty girl known as the leader of the Pretty Boy Detective Club with the nickname of “Beautiful Aesthetics Manabu”, Soutouin Manabu, and we would end up going on an adventure together. 

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14  Araragi changes 明白 (meihaku, “obvious”) to 空白 (kuuhaku, “blank space”). 
15  Araragi makes a pun on 気のせい (ki no sei, “imagination”) and 機能性 
(kinousei, “functionality”). 
16  Mayumi switches back to watashi as her first-person pronoun.