After researching "relationship ruts," Atem discovers another modern custom: anniversaries.
Determined to become the perfect example of a happily married couple, he decides they must celebrate properly. Armed with a wedding magazine, the help of A.R.E.S., and an obsession with finding the "golden ratio" of romance, he creates the ultimate anniversary plan—flowers, fine dining, a night view, matching necklaces, and even a trip back to the afterlife where everything began.
The only problem?
Neither of them can remember what anniversary they're actually celebrating.
As records from the afterlife, overly helpful AI, and an enthusiastic wedding magazine editor turn their private lives into public fascination once again, Kaiba realizes what he has known all along: every day with Atem has already been a special day.
Or: Atem tries to optimize romance like a research project, while Kaiba quietly proves that love never needed optimization in the first place.
This is a translation of an original work on Pixiv.
Original Title: 愛と理論 22 王、記念日を祝う
Original Author: 葉人(@Hathor₋yuki)
Personal site: https://prideshipping.sakura.ne.jp
The thick pink bridal magazine was, of course, already in his hands.
"…Come to think of it, we've never celebrated an anniversary."
Seto's hands stilled over his tablet.
"…You're only noticing this now."
"Apparently the world celebrates anniversaries. Married couples, people in relationships—even quantum-married ones."
"That last category contains no one except you and me."
But Atem was serious.
"If we're the only case, we have all the more reason to set an example. The magazine says anniversaries are 'the visualization of love.'"
Seto closed his eyes briefly.
"…You're still letting that editorial team bait you, even after everything."
"I'm simply obtaining necessary information. I'm being interviewed—it isn't exploitation."
"That is exploitation."
But Atem had already turned his attention elsewhere.
He pulled out a planner and was turning its pages with great deliberation.
"An anniversary is 'special time spent together'… but what does one actually do?"
Seto shrugged.
"Daily life is enough, isn't it."
"Daily life is not 'special.'"
"In your case, quantum marriage makes it special."
"But the world's common sense doesn't see it that way."
Seto sighed, exasperated—and faintly pleased with himself for finding that earnestness endearing anyway.
"So what do you intend to do?"
Atem promptly called up A.R.E.S.
"Atem-sama. Anniversary information has been organized in coordination with LOVE-OS."
Seto immediately frowned.
"…Overstepping again."
But A.R.E.S. continued, proudly:
"I've prepared a ranking of the most standard anniversary activities."
Atem nodded with satisfaction.
"Well done, A.R.E.S."
"Number one: give flowers.
Number two: go see a night view.
Number three: a special dinner.
Number four: exchange rings or necklaces.
Number five: a surprise.
Additionally, the bridal magazine's editorial department strongly recommends 'commemorative photos at a photo studio.'"
Seto put a hand to his forehead.
"…Skip the commemorative photos."
Atem asked with genuine innocence:
"Why?"
"……Something always happens."
Atem, who had accumulated quite a history of incidents involving photographs, looked away, thinking it over.
But he quickly returned to his serious expression and made a note on the page.
"Then flowers, a night view, dinner, accessories, and a surprise… yes, the modern world has a lot of ceremonial demands."
Seto leaned back and exhaled.
"So—which of these do you actually want to do?"
"All of them, obviously."
"All of them? At the same time?"
"Is there a problem with celebrating all at once?"
"Yes. Too many tasks."
Atem nodded gravely and added another note.
"Right then. I'll research 'the optimal golden-ratio method for anniversary celebration.'"
Seto gave a small laugh.
"…So in the end it comes back to the golden ratio and research."
"Research is the center of life. Love included. Which is why I need your cooperation."
That particular phrasing caught somewhere in Seto's chest.
"…Fine."
Atem smiled, warmly.
"Reassuring. The magazine also said 'an anniversary is something two people build together.'"
"…Would it be faster at this point for me to just buy that publisher outright?"
"Please don't. I'd lose my information source."
Seto laughed despite himself and placed a hand lightly on top of Atem's head.
"I don't need an anniversary. Having you is enough."
Atem went still at that, just for a moment.
"…Seto, you make me impossible to study sometimes."
"Good."
The next day.
Atem shut himself in the study, arms folded before a whiteboard bearing the words "WHAT IS AN ANNIVERSARY" and "WHAT IS A SURPRISE" in large letters.
On his head, open and balanced there, was the anniversary special issue he'd received from the magazine yesterday.
"A surprise is the act of staging 'unpredictability.' I see."
A.R.E.S. ventured a quiet interjection.
"Atem-sama, a successful surprise requires 'the other party's astonishment' as a key element. Seto-sama's perceptiveness is exceptionally high, so…"
"In other words, it won't work on Seto."
"Correct. Additionally, since an anniversary is considered 'something to be spent together'…"
Atem spread his hands without hesitation.
"Right, then surprises are off the list."
Clean. Remarkably clean.
At that moment, Seto appeared, coffee in hand.
"You've given up on the surprise?"
"The approach is too difficult to crack."
Seto didn't bother hiding his smile.
"You decided fast."
"A surprise depends on an information gap between the one staging it and the one receiving it. But lately, you see through me, read me, and get there first. The 'information gap' can't be established."
"Is that a compliment?"
"It is."
Seto glanced away, faintly self-conscious.
"So surprises are off the table for this one."
But Atem had already moved to the next section of the whiteboard.
Written there, in alarming letters:
Anniversary Plan Draft: Everything (Provisional)
Seto pressed a hand to his brow before he could stop himself.
"…Truly everything? I have nothing but bad feelings about this."
Atem launched into his explanation with absolute seriousness.
"After organizing the information from A.R.E.S. yesterday, it became clear that anniversary events in the world tend to be more effective when multiple events are consolidated on the same day."
"I've never heard that analysis before…"
"For instance: dinner plus night view. Flowers plus accessories. Surprise plus photo shoot. Arranging all of these according to the golden ratio produces a perfect anniversary."
Seto closed his eyes.
"…The golden ratio is doing too much work."
Atem gestured toward the dense cluster of notes covering the whiteboard.
"First, flowers. These offer scent, color, and visual splendor.
Next, a night view. This elevates the romance index.
A dinner provides energy replenishment and enhances communication.
An accessory exchange carries symbolic meaning.
And commemorative photos serve as documentation."
Seto laughed despite his exasperation.
"Are you writing a thesis?"
"A draft has already been saved to LOVE-OS."
"Stop that. Why does an anniversary produce a thesis. Keep it in A.R.E.S. at least."
But Atem was serious.
"Seto, I want to construct a perfect day. To do that, I need to arrange this 'everything plan' according to the golden ratio, optimize the schedule, reduce travel routes, and maximize memory efficiency."
"You're… actually going to do all of this on the day…"
A murmur of exasperation—he'd lost count of how many times now.
Atem nodded, easily.
"Of course. But there's a problem."
"Let's hear it."
"There's too much information. It's too dense to fit into a 'first anniversary.'"
"I could see that."
Atem's brow creased—then a provocative smile surfaced immediately.
"But I'm good at puzzles."
Seto's eyebrow twitched.
"That expression means trouble."
Atem spun his pen before the whiteboard and declared with full confidence:
"I will solve this 'anniversary puzzle' and arrive at the optimal solution. I will construct a day together more beautiful than the golden ratio itself."
A.R.E.S. lit up the room with what appeared to be a pleased flourish.
"Atem-sama, analysis mode is already running. Proceeding in joint operation with LOVE-OS."
Seto exhaled—slowly, deeply.
"…I'm getting pulled into your research again."
Atem turned around and smiled, quietly.
"Seto, any research is enjoyable with you."
At that single line, Seto's resistance evaporated. Not that there had been much to begin with.
"…Do as you like."
Atem surveyed the meticulously constructed golden-ratio schedule for the day and nodded with satisfaction.
The timing was perfect. The flow was elegant. Seto's preferences and energy had been optimized.
The devotion born of love had crossed into something approaching art.
Before that Atem, Seto folded his arms and let his gaze settle, gently.
"So, Atem. What anniversary, exactly, are you planning to celebrate?"
His voice was calm. Soft.
Seto was the type who kept track of everything—dates, times, what they'd done. For Seto, the concept of an "anniversary" belonged firmly in the domain of reason and evidence, with no room for vagueness.
Atem, by contrast, froze entirely.
"…That is… well…"
He could wield the golden ratio with ease—but the system of anniversaries remained entirely foreign to him.
In the first place, he was less a man who asked "when and what to celebrate" and more a man for whom every day already felt like a commemoration. It couldn't be helped.
Seto started to say it: "Every day for you is already…"
But before those words could form, Atem moved.
The King's signature decisiveness—zero hesitation.
"I'll ask the afterlife's scribe."
"You'll what?"
Atem opened the afterlife channel immediately.
His former aide, the scribe who kept the afterlife's records, answered the King's summons at once.
"During the time Seto came to the afterlife—was there anything that might qualify as an anniversary?"
"An anniversary… Your Majesty? Then I shall extract from the behavioral records of you and Seto-sama…"
A composed voice. The content, anything but.
"To begin with, 'the days Your Majesty was reluctant to send Seto-sama back to the living world' number three…"
"Hold on."
Seto tried to stop it. The scribe continued.
"On one of those occasions, Your Majesty's embrace was too—"
"That part is unnecessary."
"Say it."
Atem moved to stop it; Seto urged it on.
Either way, the scribe did not stop.
"Furthermore, 'the days Seto-sama reorganized Your Majesty's library without permission and was scolded' number two."
"I was not scolded. I simply optimized the classification system."
"Without permission."
"Additionally, there are records of the two of you talking through three afterlife dawns… and a considerable number of 'uncategorized notes' in which Your Majesty was researching Seto-sama's preferences…"
(Uncategorized?) — Seto, internally.
(There were that many…) — Atem, internally.
"The above will be transmitted to your end as well."
And A.R.E.S. received the data.
"Transmission complete. Synchronizing afterlife records with present-world data. Searching for anniversary candidates corresponding to the holidays secured by Atem-sama."
"Thirty-six viable candidates extracted. Top results are as follows."
"Thirty-six?"
"There were that many…?"
"Among the highest priority:
① The estimated day Atem-sama first recognized Seto-sama as a 'close friend'
② The day Seto-sama accepted Atem-sama's counsel directly for the first time
③ The day both parties refused to yield at the afterlife gate simultaneously, leaving the scribe at a loss
④ The day of the action judged to constitute Atem-sama appointing Seto-sama as 'Special Advisor to the Afterlife'"
"That was not an appointment. You invented a title and imposed it on me unilaterally."
"It suited you."
"Furthermore, 'the day Atem-sama's heart rate elevated upon being touched by Seto-sama'…"
"What is that."
"That one I'm not making into an anniversary."
"Removing from candidates."
The exchange had a momentum all its own. A.R.E.S. slipped into it quietly, and the room tilted in a distinctly strange direction.
Faced with the full volume of data, Atem drew a slow breath.
His eyes moved over the vast afterlife records and A.R.E.S.'s analysis, and something warm settled in them.
"…There were this many days we'd accumulated together."
Seto let his faint smile show.
"That's what I told you. For you, every day is already an anniversary."
But Atem shook his head.
"Even so—I want a day with a name. Proof that you were beside me, and I was beside you."
"Anniversary candidates, optimization complete. The highest compatibility with the holidays secured by Atem-sama is…"
A quiet pause.
"'The day both parties simultaneously decided to choose each other.'"
"That… was that day?"
"Yes. That day."
Seto's eyes and Atem's eyes met, slowly.
The afterlife and the living world fell silent together. The grains of time swayed, gently.
Its name: the day they chose each other.
Atem drew a deep breath and wrote it in the first page of the golden-ratio schedule, in careful script.
Seto watched, and narrowed his eyes, just slightly.
Not for the golden ratio. Not for logic. Purely for this one thing—that they had chosen each other.
The moment A.R.E.S.'s "optimal solution" was confirmed, Seto slowly pressed one hand to his forehead and exhaled quietly.
"…To be seen through even by the afterlife's scribe. You really are an open book."
Atem drew himself up.
"Reading the King's emotions is the scribe's duty. I am not an open book—their powers of observation are simply acute."
Seto laughed, in spite of himself, at that brazen logic.
"No, you're an open book. The afterlife's scribe said the records were so extensive that extraction was difficult."
Atem's brow creased, fractionally.
"…I'll concede that. A little."
A little was, of course, an understatement.
Atem repeated the name of the chosen anniversary, quietly.
"…'The day this came to be.'"
Seto's gaze softened.
"That day, you couldn't contain yourself and laid everything bare."
Atem cleared his throat once.
"I didn't 'lay it bare.' You 'saw through it.' 'Your feelings are already completely exposed'—those were your words, Seto. Anniversary of the Exposed Feelings Incident."
"Don't make it an incident."
"It's a fact."
Seto's shoulders dropped—but there was something almost fond in it.
He knew: the moment Atem gave something a name, the world arranged itself into something fractionally more beautiful.
Seto murmured, eyes on the schedule:
"Even so—how did you manage to 'secure' my day off? You had two meetings and a sponsor adjustment. What did you do with those?"
Atem answered, easily:
"A.R.E.S. had analyzed it as 'Seto's optimal rest day.' I simply followed that advice. Everyone else cooperated."
"Everyone? How much did you tell them…"
A deep sigh.
"In your case, there's a chance you run entirely on luck."
"At times, the flow favors a king."
Seto lowered his eyes—half exasperated, half fond.
"…You've always had absurdly good luck…"
Atem nodded, with satisfaction.
"Now I can celebrate the anniversary without worry."
Just as Atem exhaled with relief—
Seto let a faint, meaningful smile cross his face.
"…Though this day isn't only that."
"Was there something else?"
"There was. But just as you found your own anniversary—find this one yourself, in time."
Atem's brow furrowed as he looked at Seto.
"…Is this what they call hinting."
"Where did you pick up that word."
"…I'll remember it eventually."
"That tenacity is something I find admirable."
Atem opened the golden-ratio schedule again. Seto pulled up a display and asked over his shoulder:
"What do we do first?"
Atem answered with full confidence.
"'Stand at the place where it began.' The center point of the day we chose each other."
Seto stepped closer and glanced at the schedule in Atem's hands.
"…An anniversary structured on the golden ratio. That's very you."
Atem tilted his chin up, lightly.
"I'm celebrating a day with you. If it isn't in the most beautiful form possible, there's no point."
Shortly after, word arrived from Isono that Seto's schedule had been cleared.
On the morning of the anniversary, Seto's schedule displayed a perfect spiral of blank space.
The holiday Atem had "secured."
Seto adjusted his coat collar and glanced at Atem beside him, ready to go.
"…We're really starting in the afterlife."
"Obviously. That's where the coordinates of our beginning are."
Seto shrugged, slightly.
"Your scale is never anything less than enormous."
Atem only smiled, faintly, and said nothing to deny it.
"You're one to talk."
That was all he said in return.
The moment they stepped through the afterlife gate, the quiet air shifted with a ripple.
The priests lined up and bowed deeply.
"Your Majesty, happy anniversary!"
"We offer our most heartfelt congratulations on the establishment date of your emotional contract!"
"A most auspicious day—please accept this humble offering…!"
Seto went completely still.
"…You didn't leak information somewhere unnecessary again, did you?"
Atem answered with a grave expression.
"I didn't leak anything. The scribe simply analyzed it independently."
Seto pressed a hand to his forehead.
"…That scribe is dangerously competent."
Atem looked pleased.
As they were leaving the afterlife, the high priest held out a bouquet with both hands.
It was something that seemed to belong to neither this world nor the afterlife.
"We arranged the King's 'colors of the heart' and 'devotion toward Seto-sama' according to the golden ratio."
Seto looked twice.
"…Colors of the heart, in the golden ratio?"
Atem received it quietly.
"Beautiful."
"Beautiful, yes—but what exactly is your afterlife's philosophy of hospitality."
"That is simply what my afterlife is like."
"Don't say it like that's settled."
The night view.
What Atem had reserved in advance was the observation floor of an ultra-high-rise tower under Kaiba Corporation management.
Private hire.
Seto gazed at the view in silence, eyes narrowing.
"…As always, your scale shows no mercy."
"You do the same sort of thing yourself. Besides—"
Against the backdrop of the city's lights, Atem said, quietly:
"The days you fought to protect this world—I wanted to celebrate them here, in the place you protect."
Seto turned away.
It looked like nothing other than concealed embarrassment. No one commented.
A.R.E.S.'s supervised golden-ratio course.
Appearance, nutritional value, balance—all of it immaculate.
"The proportions are perfect."
"…It is good, I'll grant you that. But when you say it, I start to suspect you're in love with the ratio itself."
"I am not in love with it. I hold it in esteem."
"No difference."
In a quiet private room, Atem opened a necklace box with care and held it out to Seto.
"This is a tangible commemoration."
Seto received it without a word, fastened it around his neck, and murmured:
"…The things you choose always fit me, somehow."
"Of course. I chose it for you."
Seto, eyes still lowered, reached over and clasped the matching necklace around Atem's neck.
"…Thank you."
That single word from Atem was something like a treasure.
The end of the anniversary.
The schedule was supposed to finish here.
But Seto stood up quietly and gave A.R.E.S. some kind of coded instruction.
"Seto? What are you—"
The solid vision that materialized displayed a notification from Kaiba Corporation's HR department.
"Atem-dono. Congratulations on your first anniversary with the company. You are hereby awarded this year's New Employee of the Year."
Atem went completely still.
"…New employee? Me?"
Seto said it plainly—and with unmistakable pride.
"Obviously. Today marks exactly one year since you joined. It's awarded to the new employee who contributed most to the company."
"I don't recall contributing—"
"'Your existence was the greatest contribution'… though at this point the label of new employee is hardly appropriate…"
It was the truth. Every time Atem moved the world, the stock price jumped.
Atem's eyes shifted, slowly.
"…Seto. You're not playing fair sometimes."
"It's an anniversary. A surprise was required, wasn't it."
Atem exhaled, quietly.
As if the happiness in his chest was overflowing faster than he could keep up with.
"…Thank you."
Several days later.
A thick special edition had been placed carelessly on Seto's desk.
On the cover, elegant gold-foil lettering read:
The Ideal Anniversary, Complete Edition.
Seto opened the magazine without bothering to hide his sense of dread.
As expected.
"The Quantum-Married Couple" Feature — 36 Pages
The opening spread: the two of them receiving a bouquet before the afterlife gate.
Following that: silhouettes side by side before a night view.
The beautiful plates of the golden-ratio dinner.
The moment of the necklace exchange.
And the one shot from the photo studio that Atem had absolutely refused to cut—included as a bonus insert.
Seto pressed his fingers to his brow.
"…That is exactly why I told you to skip the photo studio."
Atem peered at the magazine and replied, evenly:
"I said I'd proceed as planned. The photo studio was a required item in the golden-ratio anniversary."
"That was one thing you could have dropped…"
"It was not droppable. Perfection must be maintained."
The face of someone stating a perfectly obvious fact.
Seto exhaled, deeply.
"So why has every detail of the anniversary leaked to this extent?"
"Because I asked the magazine questions."
"What kind of publication takes questions and walks off with all your information…"
Atem said it with a flawless neutral expression:
"There is also the possibility that a competent scribe was handling public relations from the afterlife."
"The afterlife needs to learn something about information management."
On social media, "the anniversary plan is too beautiful" was trending. The studio photo had already been adopted as the gold standard for "a shot everyone wants to take once in their life." The anniversary industry was thriving.
Seto closed the magazine and sank into the sofa.
"…This is why the world is never quiet when I'm with you."
Atem sat down beside him and leaned his head against Seto's shoulder—completely naturally, as if it were the obvious place to be.
"Let the noisy world be noisy. We can simply make another anniversary today."
Seto looked at that face from the side, and let a faint smile settle at the corner of his mouth.
"…Fair enough. Whatever the world makes of it, that's nothing new. Every day spent with you is special."
Atem narrowed his eyes, quietly.
"Right then—let's begin today's anniversary. 'Day One of the Resolved Near-Anniversary Incident.'"
"Don't make it an incident. You give too many things names."
"If something is to be recorded, it must be recorded accurately."
Seto burst out laughing and drew Atem's head in, gently, just slightly.
Outside, the special edition was selling out.
The world was buzzing over the "ideal anniversary."
But in a place no feature could reach, the two of them were adding one more anniversary to the count, as they did every day.
That was the quietest, and the most joyful, celebration in the world.
