Saito Kagami ate his lunch in silence, just like he had every other school day since the semester started.
The second week of April. Spring sunlight filtered through the classroom windows, catching specks of dust in midair like a slow, gentle snowfall. The low hum of student chatter buzzed all around him—laughing, whispering, rustling of snack wrappers, the soft clatter of chopsticks tapping against plastic bento lids.
But at the very back corner of Class 1-B, Saito sat alone, facing forward, chewing methodically through a triangular tuna onigiri. One bite every twelve seconds. He had timed it.
The rest of his lunch was arranged precisely in front of him: a half-sliced apple (no skin), a folded napkin, and a second onigiri placed horizontally to balance his milk carton so it wouldn't tip on the uneven desk.
It wasn't that he had no friends. That implied an attempt had been made. Saito simply hadn't spoken to anyone besides teachers.
He didn't see a reason to.
Social interaction was rarely logical. Most student conversations, by his observation, consisted of redundant small talk, performative sarcasm, and what he labeled "situational squealing." He had yet to figure out what was so amusing about saying "ehhh?!" in unison when someone revealed they had a pet cat.
He stared blankly at the milk carton. It had a little cartoon cow on the front.
"The average high school student begins experiencing romantic feelings by age fifteen. A majority of cases involve unprompted emotional development based on proximity and social stimuli."
That was what the book said, anyway. He had read five on the topic. Romance, courtship behavior, adolescent psychology. It was the one subject he couldn't predict.
That was why, two weeks ago, on the night before high school began, he had made a decision.
To approach romance like a scientific subject.
To treat love as a system that could be understood, measured, and, ultimately, experienced.
Hypothesis: If exposed to romantic stimuli, even a subject with no prior emotional data (myself) can eventually experience "love."
Method: daily observation, selective interaction, emotional tracking.
Duration: one academic year.
He chewed the last bite of his onigiri.
So far… no results.
After lunch, Saito placed his bento box precisely back into its cloth pouch, secured the knot, and returned to his neutral seated position.
The bell rang. Students groaned.
He didn't groan. Bells signaled structure.
Their homeroom teacher strolled in, clipboard in hand.
"Alright, take your seats—those of you who actually have seats," he added dryly, eyeing a boy currently trying to balance on the edge of his chair like a circus act.
The classroom settled. Saito sat in the third row from the back, beside the window. To his front-right was a trio of desks often occupied by one of the louder groups in class.
That was when he heard it.
"Kumi-chan, are you coming to karaoke this weekend?"
A girl with braided hair leaned toward the desk in front of him.
The girl she was speaking to didn't answer immediately. She was too busy drawing something with her finger in the fog of the window beside her.
"Oh—sorry, I spaced out. What?"
"Karaoke! This Saturday!"
"Maybe! Depends if my cousin still wants to go dress shopping with me."
Saito didn't look up, but his brain quietly registered the tone. Bright. Confident. Vaguely melodic.
"Let me know, okay?"
"Sure thing, Mika~"
And that was when the braided girl said her name again:
"Riko Kumijo is so busy these days."
Saito blinked.
Name registered: Kumijo, Riko.
That name sounded familiar. Not from memory, but from… volume. He had heard it multiple times in the last week. Usually surrounded by laughter or trailing behind some strange story.
Riko Kumijo.
He looked up for the first time.
The girl two rows ahead sat with one arm draped casually over her chair and a pencil stuck behind her ear like a flower. Her hair was tied up in a lazy ponytail, with an oversized blue scrunchie that looked like it might've belonged to a five-year-old. She was tapping the side of her desk rhythmically with her finger.
There was something... radiant about her. Not in a dramatic, sparkly shojo manga kind of way. More like a flickering sunbeam on a messy desk. She laughed easily, talked often, and didn't seem to hold anything back.
Saito noted, mechanically:
Subject appears emotionally expressive. Vocal range: wide. Social visibility: high. Likely well-connected.
He paused.
Probability of romantic development: …undetermined.
The afternoon class was mathematics.
Saito was already five chapters ahead, so he zoned out—not to nap, but to observe. That was when the unexpected happened.
A soft voice beside him.
"Hey… uh, Kagami-kun, right?"
He turned.
Riko Kumijo was leaning toward him, brows slightly furrowed, lips pressed into a hesitant smile.
"Do you have a ruler?"
Saito blinked.
A pause.
Then he reached into his pencil case and handed it to her.
She took it with both hands and a polite nod. "Thanks! Mine… broke. Don't ask."
He didn't ask.
He also didn't say anything else.
Riko held the ruler for a second longer, then tilted her head.
"…You really don't talk much, huh?"
He replied automatically. "Only when necessary."
She laughed through her nose. "You're funny."
That was objectively false.
She turned back to her desk and began measuring something on her graph paper.
He stared blankly at the side of her head.
After class, she returned the ruler without a word. Just a small smile.
Saito tucked it away carefully, then looked at the crisp, clean page in his notebook that evening.
Entry: Day 9
Subject identified: Riko Kumijo
First interaction: lent a ruler during mathematics class
Response: mild amusement (hers); confusion (mine)
Facial description: energetic expression; unreasonably bright eyes
Nickname assigned: "Serious-face-kun" (assumed; not verbalized)
Emotional note: stomach felt… warm. Possible indigestion? Will confirm.
He stared at the page for a while before closing the book.
The next day, he overheard more about her.
Apparently, she had been in the student council in middle school. She liked lemon-flavored candy. She once dyed a strand of her hair pink on a dare and had to wear a headband for two weeks to hide it.
Saito said nothing.
But he listened.
Riko still hadn't spoken to him again. She'd greet others with a wave, laugh at someone's joke, flick someone else's ear for calling her short. But she hadn't turned around in math class once that day.
He felt... something. Not sadness. That would be dramatic.
Just a mild sense of being... unnoticed.
Which was strange, because he preferred being unnoticed.
Didn't he?
That weekend, he found himself at the bookstore, standing in the relationships aisle for longer than any human being reasonably should.
He picked up a book titled "Understanding Youth Romance." It had a manga-style couple on the front.
"If she laughs at your jokes, she likes you."
"If she touches her hair while talking to you, she's interested."
"If she gives you candy, she's definitely flirting."
Saito closed the book and returned it to the shelf.
She had done none of those things.
Monday.
Riko dropped her pen during class.
It rolled under Saito's desk.
He picked it up and held it out silently.
She blinked. Then smiled and took it back.
"Thanks, Serious-face-kun."
He blinked. "That's not my name."
She grinned. "I know."
Then she turned around.
That evening, his entry was much shorter.
Subject appears to remember me. Nickname confirmed.
He tapped his pen once against the desk.
Then, for no reason he could justify, he added:
She remembered my face.
By the end of the second week of school, nothing dramatic had happened.
They hadn't become friends. They hadn't exchanged phone numbers. She hadn't invited him to lunch, nor asked about his hobbies, nor offered to walk home together under the cherry blossoms.
But she had called him by a nickname. Twice.
And she had smiled at him.
And every time she laughed—whether at someone's joke, or a weird story, or even her own mistakes—he found himself listening without realizing.
Romance, he decided, was not part of the curriculum.
It had no set formula, no test prep book, and no guarantee of results.
But even so…
As he stared down at Riko Kumijo's name in his notebook that night, circled once in pencil, he felt something he couldn't quite name.
Not yet.
But maybe, just maybe, this was how experiments started.
With curiosity.