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2025-12-28
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2026-05-13
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Problem K. The Kita Anomaly

Summary:

Tsuguko Sasaki (Codeforces Handle: tsugu, Rating: 3042, Legendary Grandmaster) views the three-dimensional world as a series of badly optimized algorithms. School is a bloated function; classmates are redundant variables; and sleep is the only O(1) operation worth executing. Her plan for junior high was simple: Minimize interaction, maximize recovery time, and wait for the program to terminate.
Then Ikuyo Kita crashed her runtime.
Kita is an unchecked loop of extroversion, strawberry scent, and zero personal boundaries. When she eventually asks Sasaki to be her "practice girlfriend" to figure out her sexuality, Sasaki accepts. The logic is sound: It optimizes idle time, provides high-quality entertainment, and prevents Kita from bothering anyone less capable of handling her quirks.
They share hands. They share kisses. They systematically steal every single "first" from each other under the label of Experimentation.
This fic is structured in chapters, but in each chapter there are a lot of little "moments". Generally each chapter is a collection of "moments" that flow together, but each "moment" is kind of an idea on its own.
Thank you to LeCakey for lending me his idea! Go check out his version too!

Chapter 1: The Variable

Chapter Text

To the outside observer, the first few weeks of my life in junior high probably looked like clinical depression.

I spent six hours a day with my forehead pressed against the desk, my posture a masterclass in scoliosis risk, barely responding to external stimuli until the final bell rang. Then, I would pack my bag with mechanical efficiency and vanish.

In reality, it was just resource management.

My nights were allocated to the Russian servers. Under the handle tsugu, I was fighting for my life in the global top 100 on Codeforces. I was currently a Legendary Grandmaster—a rating of 3042. Maintaining that rank meant participating in contests that usually ran from midnight until the birds started chirping.

Therefore, the Japanese public school system wasn't "education." It was recovery time.

The curriculum was agonizingly slow. The "trivia" they force-fed us was useless. There was nothing fruitful to be gained from talking to other kids whose biggest problem was a TikTok trend. Since I could look at a test paper and return the correct output in roughly 15% of the allotted time, I saw no reason to burn CPU cycles engaging with the simulation.

My strategy was optimization: Hibernate during the day to maximize performance at night.

I just wished I could skip the cutscenes. Being there for attendance was a mandatory constraint, but god, it was boring.

Things changed on a Tuesday afternoon.

I was deep in a REM cycle during what I vaguely recalled was 5th Period. The classroom was quiet, a steady hum of afternoon drowsiness.

Then, the interrupt signal triggered.

"Hello? Are you there?"

The voice was high. Uncompressed. Way too peppy for the ambient atmosphere.

I tried to ignore it. A firewall against social interaction.

Something poked my shoulder. Physical input.

I groaned, hazily peeling my cheek off my sleeve. I wiped a trail of drool from the corner of my mouth—extremely dignified—and blinked against the harsh fluorescent lights.

Standing over my desk was a blur of red and beige. As my vision focused, the blur resolved into a girl. Red hair. Huge eyes. A face that looked like it had never harbored a negative thought in its entire existence.

I recognized her vaguely as a background process I usually ignored.

"What?" I asked, irritated. My neck hurt like hell from the angle I had maintained for the last two hours.

The redhead gasped. She put a hand to her chest, actually recoiling as if I were a zombie rising from the grave.

"Oh! You're alive!" she squeaked.

I stared at her. "Excuse me?"

"I was so worried!" The girl leaned in, invading my personal space with zero hesitation. "Normally, you pack up and go away right after the day’s end chime. Like, zoom. But today the bell rang ten minutes ago and you didn't seem to respond at all. I poked you twice."

"You poked me?"

"I had to check!" She looked genuinely distressed, her eyebrows pulling together in a worry-knot. "What if you were to suddenly... you know, expire? Right there? And I was the last person to stay with you? I don't want to become haunted for the rest of my life, you know? Salt purification is really messy!"

I processed this statement. It took me a full second.

"Geez," I sat up, popping my back. "I’m just sleeping. Had a late night. Optimizing my schedule."

I looked at her incredulously.

"Who the hell looks at a sleeping student and the first thought that winds up in their head is 'She might be dead'?" I asked. "Have you been staring at my sleeping body for, what, ten minutes? While I knew no better? That’s hella creepy, man."

"No!" She flushed a brilliant shade of crimson. "I... I was just scared, you know? What if you were actually gone, and I was disrupting the recently deceased? I... I’m scared of spirits!"

What is wrong with this girl?

Externally, I stared at her, largely unamused and blank-faced. She was vibrating. She radiated a level of extroverted energy that felt radioactive.

Realizing the conversation was stalling, the redhead pulled a chair from the neighboring desk and sat down uninvited.

"What’s your name?" she asked, beaming. "You can call me Kita!"

"Sasaki," I said, rubbing the sleep out of my eyes. "Tsuguko Sasaki."

"Okay, Sattsu!"

I paused. "That... isn't what I said. But fine. Sasaki."

"Sattsu sounds cuter!" She waved her hand. "Anyway, Sattsu! I've been watching you."

"That helps the 'creepy' allegation."

"No, I mean, I notice people!" Kita insisted. "And you... you sleep so much! You sleep through everything. Math. History. Lunch. The teachers look at you like they want to explode, but you ace the quizzes so they can't do anything. It’s like a superpower!"

She leaned forward on my desk, her eyes sparkling.

"How can you sleep so much, though?" she asked genuinely. "There’s just so much fun to be had at school!"

"Fun?" I raised an eyebrow. "Not that I have anything strictly against the concept, but so far I haven’t found anything of interest here. Classes are solved problems. I haven't found anyone interesting enough to interact with. I'm not up to the silly games you kids usually do. And hanging out... well, I can do that alone. No point in dragging others into my downtime."

"Haaah?!" Kita let out a dramatic gasp. "That sounds so negative! There are so many things to do over here!"

"Consider me unconvinced," I muttered, reaching for my bag.

"Then!"

Kita slammed her hands onto the desk.

"There’s a popular bakery serving real good strawberry jam-filled donuts nearby! Three streets over! People on Isosta said that they drop a fresh batch at 3:30, and there won't be a line! We have..." She checked a nonexistent watch, then her phone. "...twenty-five minutes! Would you like to go out with me?"

She dumped three different proposals, a location, and a rigid timeline into a single breath.

I looked at her.
I looked at the clock.
It was 3:20 PM. Codeforces Round #559 didn't start until later tonight. My queue of tasks was empty.

"We’ve only talked with each other for five minutes," I observed. "And you’ve already concluded I need sugar?"

"Yes! Where did that boredom even go?" She grinned, blindingly bright. "You sounded so lazy just a few seconds ago! Come on! Strawberry jam!"

I hesitated. A Grandmaster knows when to calculate risks. But a Grandmaster also knows that running on empty stamina is suboptimal. And frankly, Ikuyo Kita was the most complex variable I had encountered in this building so far.

"Deal," I said. "But you're buying one."

"Yay! Let's go, Sattsu! Adventure!"

She grabbed my wrist—her hand was startlingly warm—and pulled me toward the door.

It’s not like the Tsuguko Sasaki of back then had anything better to do anyway.

It turned out that the girl’s given name was Ikuyo.

In most datasets, nomenclature has zero correlation with behavior. But in her case, "Ikuyo" (Let's Go) wasn't just a name; it was a runtime instruction. It was a `while(true)` loop that dominated the next few weeks of my life.

Before Kita, my daily algorithm was deterministic: School → Home → Grind AtCoder/Codeforces problems until eyes bleed → Sleep. It was efficient. It was O(1).

After Kita, my life became dominated by stochastic processes.

It felt as if the specific millisecond I decided to begin my recharge cycle—when my head hit the desk or I opened a manga—Miss "I’m Here! Let’s Go!" would spawn out of the ether.

"Sattsu! There's a cat café two stations away! The reviews say the coffee is terrible but the cats are 'charmingly ugly'! Let's go!"

"Sattsu! I found a shrine that sells omamori for good hair days!"

"Sattsu! 24-hour Karaoke! I heard their fried potato wedges are decent!"

My firewall failed every single time.

Logic dictated I should refuse. Time spent wandering aimlessly was time deducted from my training rating. I was hovering around 3042 rating points; slipping back into International Grandmaster was not an option.

But for some reason I couldn't quantify, I couldn't execute the refusal command.

Maybe it was momentum. Trying to stop Kita was like trying to halt a recursive function without a base case; you just stack overflowed. Or maybe it was simply that, compared to grinding tedious implementation problems or staring at the ceiling, getting dragged by Kita toward some niche, weird-ass spot I never would’ve visited otherwise... was actually high-yield entertainment.

The destinations were volatile.
The themed cafes were almost universally tourist traps (Algorithm: Maximized aesthetic, Minimized taste).
The "scenic spots" were usually crowded with Isosta influencers.

But the 24-hour karaoke bars? Surprisingly efficient. Good acoustics, cheap food, and Kita had the voice of an angel, even when she was screeching J-Pop.

What fascinated me most, however, was her processing behavior.

I observed her input/output with other agents. Kita treated everyone like this. The cashier. The random grandmother on the bus. Me. She radiated 100% unfiltered, honest, extroverted energy. It was terrifying. I couldn't fathom how anyone gathered the sheer caloric density required to live a life like that without crashing.

I concluded one thing with certainty: Ikuyo Kita was cute.
And she was perfectly capable of weaponizing this cuteness—a frontend UI so pleasing that no backend logic could reject her requests.

But as we approached the three-week mark, I noticed a discrepancy in the data.

The sheer volume of runtime we spent together didn't compute.

From my side, the logic held: I had no other friends (Friend Count = 0), no club activities (Time = Free). I was an available resource.
But Kita? By week three, she had amassed a friends list that looked like a connected graph of the entire school.

So why was she allocating so much time to me?

She walked me home every day. She dragged me to weekend spots. She sat with me during lunch while I played idle games.

If she spent this much time with all her friends, she would need to be running parallel instances of herself. Since cloning technology doesn't exist outside of bad sci-fi, and she clearly hadn't mastered time dilation, this was a Knapsack Problem that didn't fit the constraints.

Was I a special case? An outlier? Or just a convenient edge node in her network?

Then came the outlier event.

We were walking home. I was mentally debugging a solution for a dynamic programming problem involving bitmasks.

"Hey, Sattsu," Kita chirped, swinging her bag.

"Hn?"

"My mom wants to meet you."

My processing stalled. "Excuse me?"

"My mom! She wants you to come over for dinner this Friday!" Kita spun around, beaming. "And then sleep over!"

I stopped walking.
Who invites a "friend" they’ve barely known for three weeks to a sleepover?
A sleepover implies a high level of trusted access. It involves sharing domestic space. Seeing the user in their default state. Dealing with parental units.

"Kita," I said slowly. "We’ve known each other for 21 days."

"And?" She tilted her head. "We hang out every day! My mom is super curious. She keeps asking, 'Who is this Sasaki-san you're always texting?' She demands an inspection!"

"An inspection," I repeated. "Your mother is a freak?"

"Oh, totally," Kita laughed, completely unbothered. "She’s intense! But she cooks really good hamburg steak. Come on, Sattsu! It beats going home and playing with your computer code numbers, right?"

I calculated the odds.
Refusal leads to: More pestering. High probability of Kita showing up at my house uninvited.
Acceptance leads to: Free food. A glimpse into the source code of Ikuyo Kita (her home environment).

And, honestly?
I looked at her face. The 'cutie-patootie' expression she deployed with ruthless efficiency.

"Ain't no way," I muttered to myself. "How is a human supposed to return false against that UI?"

"Fine," I sighed. "But if your mom is weird, I'm escaping through the window."

"Yay! It's a date! Er—I mean, a sleepover!"

I ignored the slip.

I didn't realize it at the time, but accepting that invite was the moment I stopped viewing Kita as a random variable and started viewing her as a main parameter. I thought I was just accepting free dinner. In reality, I was walking blindly into a dependency I would never be able to uncouple.

Our first sleepover began as abruptly as every other subroutine in the Kita operating system.

I arrived at her apartment complex, which was only a fifteen-minute walk from my own base of operations. The neighborhood was painfully normal—suburban quiet, manicured hedges, the kind of place where people actually sorted their recycling correctly.

I entered the domain. I met the admin.

Kita’s mother was… intense.

If Ikuyo Kita was a high-bandwidth broadcast signal, her mother was a denial-of-service attack. She looked like Kita, but sharper. Her energy wasn't bubbly; it was inquisitive.

"So, you’re the Sasaki-san! Ikuyo talks about you endlessly. Are your grades good? What do your parents do? Do you play sports? Why do you sleep so much? Is it iron deficiency?"

I endured the barrage with the stoicism of a server handling bad requests. I ate the trendy food they served (some viral avocado dish Kita insisted on making). I nodded at the right intervals.

I quickly updated my internal model: With a mother this overwhelming, it was no wonder Kita turned out to be an attention-seeking extrovert. It was a defense mechanism. She had adapted to a high-pressure environment by becoming the loudest object in the room.

By 8:30 PM, the protocol dictated that I should return home.

"Well," I said, checking my phone. "My scheduled uptime is ending. I should—"

"Eh?" Kita appeared at my elbow. She unleashed the Puppy Dog Eyes. It was a critical hit.

"Stay!" she pleaded. "It’s Friday! Mom said it’s fine! You can borrow my pajamas! Please, Sattsu? If you leave, I have to listen to Mom talk about neighbor drama!"

Logic: Refusing leads to going home and grinding algorithms.
Heuristic: Staying leads to further data collection on the Kita Variable.

"Fine," I sighed. "But I'm taking the side of the bed near the outlet. My phone needs juice."

The transition to the bedroom phase revealed more legacy code. We engaged in standard "girl talk"—a chaotic format of conversation with no clear topic sentence or conclusion. Kita spent thirty minutes assuring me that, yes, her mother interrogates everyone like that, and no, she isn't actually an undercover cop.

Then came the deployment of sleep mode.

Kita’s room was violently pink. It smelled of strawberries. She tossed me a spare set of pajamas that were dangerously frilly, but soft.

"Lights out!" Kita chirped, jumping into the double bed.

I sat on the edge, checking my social media feeds. "Goodnight."

"Sattsu," Kita’s voice came from the pillow.

"What."

"Be my body pillow."

I froze. I turned to look at her. Kita was lying on her side, arms open, expecting immediate docking.

"Denied," I stated flatly. "It is a humid night. Human body heat transfer is inefficient. Also, I require personal space to maintain sanity."

"Ehh?" Kita pouted. "But I want to hug something!"

"Hug the actual pillow."

"It doesn't have bones!"

"That is generally considered a feature of pillows."

I turned back to my phone, satisfied that the logic held.

Then, impact.

Whump.

A fluffy, memory-foam pillow collided with the side of my face at high velocity.

"Sattsu is stingy!" Kita accused.

Before I could recover from the projectile, Kita lunged. She pinched my cheek—hard. She stretched the skin.

"Just! Come! Here!" she commanded, abandoning her cutesy voice for something surprisingly forceful.

I was stunned.
It wasn't the pain; the pinch was relatively mild. It was the realization that Kita, the people-pleaser, the radiant idol-in-training, had just assaulted me because she wanted cuddles.

"Okay! Okay! Release the face!"

I swatted her hand away and flopped onto the bed, surrendering to the demand.

We shuffled under the blanket. The geometry resolved itself quickly. I lay on my back. Kita latched onto my side like a koala, draping an arm over my waist and burying her face in my shoulder.

"See?" she murmured, sounding disgustingly satisfied. "Cozy."

I stared at the ceiling, waiting for the repulsion to hit. I expected to feel trapped. I expected to be annoyed by the hair tickling my neck.

But the repulsion didn't compile.

Instead, my heart rate slowed. The weight of her arm was... grounding. It felt like weighted compression gear. Warm. Solid.

There were three critical updates to the dataset that night:

Observation 1: Intimacy is optimized for serotonin.
I had purposely opted out of physical touch for roughly five years because it seemed inefficient. I was wrong. Hugs and cuddles were apparently extremely effective at lowering cortisol levels. This was dangerous knowledge.

Observation 2: Kita has a hidden variable.
The usual "Customer Service" Kita is fine. But the Kita who throws pillows at my face when rejected? The Kita who forcefully acquires what she wants? That was comedy gold. It was a chaotic deviation from her standard script. I realized then that I would tolerate a lot of nonsense if I could get her to break character like that again.

Observation 3: I am stuck.
Kita’s sleeping posture was atrocious. She kicked. She mumbled. But some time around 2:00 AM, I woke up and looked at her face in the moonlight. She was drooling on my shoulder. She looked unguarded and stupidly peaceful.

I found myself watching her instead of sleeping. I memorized the shape of her eyelashes.

This is going to become a recursive loop, I realized with a sense of dread. I'm going to end up acting as a pillow for the foreseeable future.

Strange. I didn't want to terminate the process.

If I were to run a diagnostic on my own emotional state during Year Two of junior high, the logs would return a lot of warnings.

Warning: Unexpected heart rate acceleration at timestamp 08:30 (Kita’s arrival).
Warning: Dopamine release triggers shifted from Algorithm Solved to Redhead Smiled.
Warning: Buffer Overflow in the affection sector.

To the layperson, or perhaps to the shoujo manga protagonist, these are signs of falling in love. Romantically. Apparently.

But I am a Legendary Grandmaster. I don't operate on "vibes." I operate on causality. And looking at the data, I determined that nothing had actually changed in my core programming. It was just a natural response to stimulus intensity.

Think about it: Kita was a variable that introduced statistically significant "firsts" into my life on a daily basis. Before her, my world was bounded by school, my bedroom, and the glowing blue screen of an IDE.

Kita grabbed the bezels of my reality and dragged them wider.

The festivals. The detours. The pillow fights that devolved into legitimate grappling matches where I realized she was shockingly strong. When someone forcefully inserts that much new data into your life, it is only logical to become attached to the source.

And then there was the physical aspect.
Intimacy, I discovered, is one hell of a drug. It operates on basic biological triggers. Oxytocin. Serotonin. Evolution wired us to enjoy warmth. If you spend five years actively opting out of physical touch to maximize coding efficiency, and then suddenly you are cuddling, spooning, and essentially smooching a girl every other day? You are going to become addicted. It is not romance; it is withdrawal management.

So, I let it run. I reasoned that it was the most efficient way to enjoy my youth.

When the tables turned and I had to initiate the schedule—because even an infinite energy source like Kita needs recharging, and apparently I was the designated charger—I stuck to my strengths: Pathfinding.

"We’re going out," I’d say on a Saturday.

"Where?" Kita would ask, bouncing in place.

"Uncharted territory."

We got bicycles. It was illogical; I possess the athletic ability of a damp towel. But public transport follows fixed edges and nodes. Bicycles allow for free traversal of the graph.

I dragged her to the weird parts of the Tokyo Metropolitan Area. We rode along riverbanks where the buildings looked jagged and old. We found lookout spots on elevated roads that offered a view of the concrete skyline, pretending for a few minutes that we were the only two inputs in the simulation.

Ideally, these moments felt like scenes from that existentialist manga about two girls wandering a post-apocalyptic world.
Realistically, we usually ended up sweating, covered in dust, eating convenience store ice cream on a curb while Kita complained about her bangs.

And I loved it. I loved watching her process the world I lived in—the quiet, the niche, the dusty.

"Sattsu!" she’d yell, pointing at a rust-covered sign. "That looks aesthetically pleasing! Take a picture!"

"It's a warning sign for industrial waste," I’d point out.

"It’s vintage!"

Eventually, we reached the media consumption phase.
I am not a film critic. My taste in media leans toward the "trashy but efficiently paced." Michael Bay explosions. Early 2000s romcoms with plot holes you could drive a truck through. Anime with episode counts bordering on the four-digits.

Watching these with Kita was an experiment in endurance.

She treated every piece of media as a documentary.

"Wait, why did the car explode? He just kicked the tire!"

"Physics engine bug," I explained, munching on popcorn.

"But they were in love! Why did he leave her at the airport?"

"Script requirement. Conflict generates runtime."

I found that I wasn't really watching the movies. I had seen them all. I was watching Kita.
I watched her face twist in genuine confusion at plot contrivances. I watched her tear up over manipulative sad music. I watched her hide her face in my shoulder during the PG-13 action sequences.

It was mesmerizing. It was better than the movie.

"You keep staring at me, Sattsu," Kita accused one night, pausing a generic zombie flick. "Is there popcorn on my face?"

"No," I said, not looking away. "I’m just... gathering user feedback."

"You weirdo," she giggled, and threw a piece of popcorn at my forehead.

In my defense, the hypothesis seemed solid.
We spent all our time together.
We touched constantly.
I prioritized her happiness over my sleep schedule.

In the Codeforces ranking of life, this felt like a stable solution. I didn't need to label it. I didn't need to compile it into a definition like "girlfriend" or "dating." It was running bug-free.

Which is why, when summer break of our second year rolled around, I was completely blindsided by the runtime error that was about to occur.

I thought we were operating on the same logic. I assumed we were both running the Greedy Algorithm—just grabbing the happiness right in front of us.

I didn't realize Kita was actually trying to solve a different problem entirely.

Every complex system eventually encounters an edge case that crashes the logic.

It happened at the beginning of summer break in our second year. The humid heat of Tokyo was just starting to settle in, turning the asphalt soft. We had just returned to school after a prolonged period of what the media called "The New Normal" (masks, distance, online classes that I naturally slept through).

Ikuyo Kita approached me with a look on her face I had never seen before.
It wasn't her usual blinding beam. It wasn't the frantic, overstimulated vibration of exam season.
She looked... solemn. Determined. Like she was about to ask a teacher to change her grade.

"Sattsu," she said, her voice unusually low.

"Hn?" I looked up from my Switch.

"Could you go out with me?"

Codeforces Error: Runtime Error on Test 1.
Segmentation Fault.

If this were any other human being, the syntax would be clear. Subject A asks Subject B to initiate a romantic relationship.
But this was Kita. She operated on chaos logic.

"Define parameters," I said, putting my game console down. "Do you mean... like... physically exit the building? We do that every day. Or do you mean..."

I gestured vaguely with my hands.

Kita remained fidgety. She looked down at her shoes, twisting a lock of red hair around her finger.

"I mean... go out. Date. Be... girlfriends."

Silence.
A cicada screamed in the distance.

"So," I started slowly, my brain scrambling to debug this input. "You like me? Like... romantically?"

"I... I think so!" Kita looked up, her eyes wet and distressed. "Sorry! I know it’s unreasonable! I know it’s weird!"

"It’s not weird," I corrected instantly. "It’s just statistically improbable. Are you sure you haven't been hacked? Did you download a virus?"

"No!" Kita puffed her cheeks out. "I just... I realized recently that I might... I might like girls."

"Oh."

I sat back. This was new data.
"Interesting. How did you derive this conclusion? Did you watch too many TikToks? Lesbian couples on Isosta?"

"I just..." Kita’s face turned pink. "I look at other girls and I feel... things. Like, fluttering things. The things people write songs about!"

"Okay," I nodded. "Validity confirmed. Congratulatisons on the discovery. But here is the syntax error: Why me?"

I pointed at myself. I was wearing an oversized t-shirt that said ‘Reboot’. My posture was awful. I had bags under my eyes from a contest two nights ago.

"You have hundreds of friends, Kita. Prettier friends. Friends who smile back. Why are you deploying this request to the server with the darkest interface?"

Kita looked at me. The shyness evaporated slightly, replaced by a desperate earnestness.

"Because I trust Sattsu," she whispered.

She took a step closer.

"I’m scared, Sattsu. If I tell my other friends... what if they judge me? What if I ruin the group dynamic? Everyone thinks of me a certain way. If I start... acting weird, or liking girls, they might leave."

She reached out and grabbed my hand. Her palms were sweating.

"But you won't," she said firmly. "You see all my weird sides. You see me chew pen caps and act crazy. You never judge me. You’re... reliable. You’re the only person I can experiment with."

Experiment.

There was the keyword.
I ran the logic through my head.

Proposal: Start a relationship.
Goal: Allow Kita Ikuyo to test the waters of her sexuality in a sandbox environment without risking her reputation in the wider social network.
My Role: Debugger. QA Tester. Safe zone.

"So," I summarized, "you want to use me as a practice run to figure out if you're actually gay?"

Kita flinched. "That sounds bad when you say it like that! I do like you, Sattsu! I really like being with you! That’s why it has to be you!"

"It implies," I continued, ignoring her panic, "that I am a temporary function. A beta test."

"Sattsu..."

I looked at her.
She looked terrified. She expected rejection. She expected me to tell her that using a friend for romantic experiments was inefficient and cruel.

But I wasn't a moral philosopher. I was a competitive programmer.
And in programming, there is a concept known as the Greedy Algorithm. It creates a solution by always choosing the most immediate, beneficial option available at that moment, without worrying about the global consequences.

If I said no:
We stay friends. She figures this out with someone else. I lose my access rights.

If I said yes:
I get to hold her hand. I get to claim her time. I get to upgrade my permissions from "Friend" to "Partner," even if the foundation is shaky.

Was it logical to enter a relationship explicitly labeled as "Experiment"? No. It was a high risk of future crash.
But looking at Kita’s face—flushed, hopeful, terrifyingly cute—I knew I didn't care about the future complexity.

I wanted the immediate payout.

"Okay," I said.

Kita blinked. "Okay?"

"Deal," I confirmed. "Tsuguko Sasaki and Ikuyo Kita. Status: Dating. Effective immediately."

"Really?!"

"Yes. But don't expect anything drastically different," I warned, standing up. "We already hang out constantly. You already invade my personal space. The delta will be minimal."

"Sattsu!"

Kita squealed and launched herself at me. She tackled me into a hug, burying her face in my neck. She smelled like strawberries and relief.

"Thank you! Thank you, Sattsu! I promise I’ll be the best girlfriend ever! I’ll practice so hard!"

I patted her back awkwardly. "Sure. Just don't break my ribs."

System Update: Variable Relationship_Status updated to: TRUE.

I held her in the summer heat, listening to her talk about all the things she wanted to try ("Holding hands properly! Sharing crepes! Maybe a k-k-kiss?!").

I thought I was smart. I thought I had gamed the system. I thought I could accept the label of "Experimental Girlfriend" and remain emotionally detached, enjoying the perks without the cost.

It was, in hindsight, the most inefficient code I have ever written.
I thought I was running a simulation.
I didn't realize until much, much later that you can't run a simulation on the main server without corrupting the database.F

"Let's go home, Kita," I said, suppressing a smile. "I'm hungry."

"Yes! Let's go!"

And just like that, I let the red-headed variable overwrite my entire operating system.