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“I still can’t believe we’re actually going to be living together! Funny how everything worked out, huh?” Isagi laughed as he carried another box into their new apartment.
Kaiser answered with an unenthusiastic smile, masking his irritation. Why did this idiot make it sound as though moving in together had happened by pure chance instead of being a hard-earned achievement? An achievement Michael had spent years working toward. He had come all the way to Japan just to see him, then followed him from match to match, from club to club, drawing closer with every step. It had taken him three years to go from sworn enemy to official boyfriend. He had tried countless strategies and theories to make Yoichi finally give in and agree to live with him—and now the idiot was acting as though all of Kaiser’s efforts had simply been the whim of fate?
How infuriatingly adorable.
Still, Kaiser had achieved his goal, and he was immensely pleased with himself. At last, he could forget the sleepless nights before dates, wondering which flowers to bring and whether he’d earn that longed-for goodbye kiss. He no longer had to worry about teammates catching them in a compromising position in the locker room. No more returning alone to an empty apartment or hotel room, miserably waiting for their next meeting like a puppy abandoned by its owner.
Everything had changed. Now Kaiser knew for certain that Isagi loved blue irises, and that the kiss he wanted was his whenever he wished. Now everyone on the team knew about their relationship. Now he would always be coming home to someone waiting for him.
The realization filled Michael with a deep sense of peace and long-awaited calm. It felt as though the hardest part was behind him, and all that remained was to enjoy the fruits of his labor.
Or was it...?
New challenges were already waiting for him. As it turned out, he had absolutely no idea what it was like to live with another person.
Michael Kaiser had spent his entire life alone, accustomed to simplicity and a complete lack of domestic indulgence. Even after he began earning serious money, he never wasted it on pointless luxuries. His old bachelor apartment was still half-empty, furnished with only the bare essentials and utterly devoid of decoration or anything resembling comfort.
That was why he couldn’t understand why Isagi had insisted on buying two porcelain birds during one of their shopping trips, only to place them on a shelf in the living room afterward. He couldn’t understand why two people needed an entire matching set of mugs. He couldn’t understand why every dry ingredient in the kitchen needed its own separate jar, or why the soap in the kitchen and the bathroom had to smell different.
Isagi had always surprised him with his unpredictability. But over the years, Kaiser had convinced himself that he knew him well enough to anticipate his actions and understand his motives. As it turned out, playing on the same field and living under the same roof were two entirely different things. Before long, Michael realized there was still one side of Isagi Yoichi that remained a mystery to him—the side that emerged the moment he stepped through the door of their apartment and peeled off his training kit.
Yoichi-the-human.
The one who woke up every morning and sleepily shuffled to the bathroom to brush his teeth, drank coffee and ate sticky rice for breakfast, ran to the grocery store, cooked dinner, passionately commented on football matches on television, slept for hours on rainy days, and absolutely hated loading the dishwasher.
And so, to understand this baffling creature and learn how to coexist with him, Kaiser decided to return to an old method.
His observation journal.
Back when their rivalry had been at its fiercest, Kaiser had kept a thick notebook filled with everything he could learn about Isagi Yoichi. His height, weight, training schedule, match statistics, favorite techniques on the field, every strength and every weakness. It had once been the key to standing against his greatest rival.
But anyone flipping through the notebook would notice that somewhere around the middle, the entries began to change. Wedged between tactical diagrams and match analyses were brief little notes. Plans for their next date. Restaurant addresses. Flight schedules between Germany and Japan. Later came movie tickets and boarding passes glued to the pages, tiny photographs, and postcards. At some point, the notebook tracking an opponent had quietly become the diary of a lovestruck schoolboy, filled with memories of the object of his affection.
If anyone Kaiser knew had ever discovered it, they probably would have laughed themselves sick. Kaiser himself saw nothing embarrassing or ridiculous about it. As far as he was concerned, knowing your rival’s dominant foot was just as important as knowing his favorite meal.
And now it was time to resume his observations. Because after everything he had worked for, Kaiser had no intention of suffering an unexpected defeat in his relationship.
During the first two weeks of living together, Michael paid close attention to Isagi Yoichi’s everyday habits. In that short time alone, he gathered more than enough information. One day, while Yoichi still hadn’t returned home, he pulled out the now thoroughly worn notebook and prepared to make a new entry.
His first observation concerned sleep.
Every morning, Isagi set his alarm for seven o'clock, so he could shower, make a quick breakfast, and drag Kaiser—who despised early mornings—out of bed. At night, he always fell asleep first, often nodding off in front of a recorded match or on Kaiser’s shoulder while the latter was reading. And every weekend, he would jolt awake and angrily scold himself for forgetting to turn off that same weekday alarm.
After considering all of this, Michael wrote himself a brief note:
“Send him to bed before midnight. Any later and he starts falling asleep on his feet. Turn off his alarm Friday night.”
Before long, Yoichi himself hardly noticed that he always ended up in bed just as his eyelids became unbearably heavy. Nor did he notice that weekends had finally become restful, uninterrupted by the infuriating blare of his alarm.
The next observation came from Isagi’s oddly selective attitude toward tableware. Or rather, toward those very mugs from the matching set they had recently bought.
One morning, Kaiser brewed coffee for the two of them. He knew perfectly well how Yoichi liked it. And yet, for some reason, that morning the mug remained half full. The day before, he had made it exactly the same way, and Isagi had finished every last drop.
Most people would probably have assumed that someone simply hadn’t felt like drinking that much coffee. But Kaiser was not most people.
A random whim like that didn’t strike him as random in the slightest. He was convinced there had to be a reason behind the sudden refusal. And he was right.
The next day, Yoichi brewed the coffee himself and drank every drop. Kaiser spent ages replaying the previous three days in his mind, searching for the mistake he’d made. Then, on the fourth day, when it was his turn to prepare the cursed coffee once again, Isagi obediently emptied the mug. That was when enlightenment struck. It was the mug. Out of the set of six different-colored mugs, Yoichi preferred the blue one. And when his coffee had been served in the yellow mug that day, he simply hadn’t bothered to finish it.
Pleased with the success of his investigation, Kaiser made another note:
“Only drinks coffee from the blue mug... Though honestly, what was the point of buying six if he only likes one?”
His triumph didn’t last long. One evening, Isagi unexpectedly left his tea unfinished—in what Kaiser had believed to be his beloved blue mug. Kaiser’s eye twitched. What was wrong this time? Did his boyfriend really change his preferences that quickly? Should he be worried too? A sudden stab of wounded pride hit him, accompanied by an inexplicable pang of sympathy for the rejected mug.
Fortunately, the answer came soon enough. One more day of observation yielded results. When it came to tea, Isagi wanted the red mug. Kaiser couldn’t make sense of such bizarre behavior, but he dutifully recorded the information in his journal all the same.
Little incidents like these kept happening all the time.
Yoichi never stopped surprising him. And his hopelessly obsessed boyfriend frantically tried to memorize every one of those habits, doing everything he could to make him comfortable.
For example, Isagi was astonishingly irresponsible when it came to his phone and its charger. He would fall asleep with the screen still on, constantly forget to check the battery level, and always kept both the brightness and the volume at maximum. It was no wonder the poor thing barely lasted a full day. Only when the battery started flashing a desperate red would Yoichi finally realize, then race around the apartment yelling as he searched for the charger he had, as usual, misplaced somewhere.
Practical as ever, Kaiser found a solution almost immediately. Before long, every outlet in the apartment had its own charger beside it. And another note appeared in the journal:
"Check that chargers are always available. Always put a spare one in his bag."
To his surprise, Isagi never even questioned why the thing he needed was suddenly always within arm’s reach. He simply chalked it up to a sudden streak of good luck.
Another trial for Kaiser came in the form of a simple phone call. He had been at the grocery store near their apartment, calmly placing the items from the shopping list into the basket, when his phone rang.
“Hey, grab something sweet too!”
“What exactly?”
“Anything!” Isagi chirped before hanging up.
Michael froze in confusion. In front of him stretched the entire sweets aisle. Dozens of shelves. Hundreds of choices. What exactly qualified as anything? What was Yoichi in the mood for? Silently cursing himself for lacking telepathic abilities, Kaiser tightened his grip on the shopping list. Cream wafers or chocolate cookies? Marshmallows? Gummy candy? That suspicious rainbow-colored thing that was probably made entirely of chemicals? What?!
His mind raced through every scrap of information he had ever gathered. On one of their dates, Isagi had chosen strawberry ice cream. But it was winter now—would he even want ice cream? In one interview, he'd mentioned liking sour gummies. But there were at least ten different kinds on the shelf, so which ones did he mean? On their recent trip, they had shared soft Belgian waffles dusted with powdered sugar, but Kaiser couldn't find anything remotely similar.
Driven to despair, he grabbed the first thing within reach, tossed it into the basket, and practically fled the store.
“What took you so long?” Isagi asked when his boyfriend returned after forty minutes instead of the promised twenty. “...What's that?”
“'Something sweet'," Kaiser muttered darkly as he set a two-kilogram bag of raw cane sugar on the table.
Yoichi laughed so hard and so uncontrollably that Michael felt an overwhelming urge to spank the little brat. The idiot had assumed Kaiser was making a joke, never realizing that the bag of sugar had been the product of genuine desperation. That night, after the sweet tooth had fallen asleep, Kaiser sat in the dim light, furiously scratching his pen across the page.
“‘Something sweet’ means anything except sugar.”
Not all of Michael’s headaches, however, came from fleeting whims. There was one thing that set Yoichi apart from most people. His heightened sensitivity. Until then, Kaiser had considered it nothing but an advantage. Isagi could melt beneath the lightest touch, and watching that happen was both immensely satisfying and just a little amusing. What he had failed to realize was that this sensitivity extended far beyond the bedroom.
One chilly evening, while they were out for a walk before bed, Kaiser noticed Yoichi shivering so hard his teeth were chattering. Like the perfect gentleman and attentive boyfriend he was, he immediately pulled off his warm wool sweater and draped it over Isagi's shoulders. At first, Yoichi thanked him. But only a few minutes later, gratitude gave way to an increasingly obvious frown. He kept shrugging his shoulders, tugging at the cuffs, stretching the collar away from his neck. Michael watched in real time as his boyfriend's previously cheerful mood deteriorated minute by minute for reasons he couldn't understand. The worst part was that Yoichi couldn't explain it either.
Then, a hazy memory surfaced. Long ago, Isagi's mother had once told him stories about Yoichi as a child—how he used to cry and desperately try to tear his clothes off whenever the fabric felt too rough against his skin. That very evening, Kaiser removed every synthetic and scratchy garment from his wardrobe. The last thing he wanted was for Yoichi to stop hugging him—or borrowing his clothes—because they felt unpleasant against his skin. After thoroughly cleaning out his closet, he added another entry:
"Nothing synthetic, scratchy, or slippery against the skin. Only natural fabrics and soft wool."
Besides those unconscious quirks, there were also the things Isagi did intentionally. Like the movies he picked for them to watch together. It took Kaiser quite a while to notice the pattern.
One evening, Yoichi announced that he wanted to watch a movie and put on some detective film. Feeling particularly playful, Kaiser started flirting with him barely ten minutes in. Completely engrossed in the plot, Isagi answered with an irritated hiss, ordering him to wait until the movie was over.
The next time, things went rather differently. They were watching some ridiculous romantic comedy. Inspired by all the romance on screen, Isagi suddenly found himself in the mood for a little romance of his own, happily returning Michael's advances.
Eventually, horror movies became Kaiser's favorite genre. Because whenever Yoichi put on another scary film, it meant only one thing. In five minutes, he'd start pretending to be terrified. He'd snuggle closer, jump dramatically at every scare...
And before long, the screams and moans of the dying characters on tv would be drowned out by screams and moans of a very different kind.
One page of the secret journal read:
"Detective movies—we watch to the end. No chance. Everything else—worth trying. Horrors—he's ready before the movie even starts."
Kaiser's favorite entry, however, came after returning home from a short away trip. The moment he stepped through the front door, something warm buried itself against him with a melancholy sigh. Something that smelled suspiciously familiar.
“Did you use my shampoo?” Kaiser asked, ruffling the black hair of his boyfriend wrapped around him.
“No... Well... A little,” Yoichi admitted reluctantly. “I missed you.”
He had only been gone for four days. But Isagi had missed him terribly. To make the apartment feel a little less empty, he'd wandered around wearing Michael's shirts that still carried his scent, using his shower gel and shampoo. The confession warmed Kaiser's possessive heart. He teased Yoichi mercilessly until the other admitted just how lonely and miserable he'd been by himself.
Only then did Michael happily record another observation.
"Leave a few worn shirts before trips. Keep an extra bottle of shampoo."
If only Kaiser had known that very soon, he'd be the one forced to make embarrassing confessions.
**
Yoichi was trying to reach his sports bag from the top shelf of the closet. One infuriatingly tall person in this household simply refused to understand that Isagi's belongings had no business being stored somewhere he couldn't reach.
Grumbling under his breath and hopping onto his toes, Yoichi finally managed to grab the bag. In the process, however, he knocked something lying beside it. A thick notebook hit the floor with a loud thud.
What's this? Curiosity got the better of him. He opened it. Across the first page, written in bold, sweeping handwriting, was the title:
Opponent Analysis: Isagi Yoichi
Yoichi couldn't help smiling. He'd once had a notebook just like this himself. Back then, he'd been just as obsessively fixated on his rival, carefully recording everything about Kaiser's style of play. He hesitated. On the one hand, it was Kaiser's private notebook. He really shouldn't read it. On the other... It was about Yoichi himself! Didn't he have the right to know?
So Yoichi kept reading. The first dozen pages made his eye twitch and his teeth grind as he worked through Kaiser's unbearably smug plans for defeating him. And then...
Then he found the short little notes. Addresses of his favorite restaurants. Phone numbers for flower shops. Those first hesitant words of affection. Old tickets. Postcards. Photographs.
Just as the deeply moved Isagi was about to shed his first tear, the notebook entered its next "section." The entries were recent. And they described situations that felt suspiciously familiar. Only then did Yoichi understand.
So that was why he'd been sleeping so well lately. Why there was always a phone charger nearby. Why Kaiser's clothes somehow felt especially soft and comfortable. Why his tea and coffee always tasted just right.
Kaiser had been trying so hard to make him happy. Trying so hard to make his everyday life a little easier. Trying so hard...
Because he was afraid of losing him. Isagi sighed, smiling to himself.
Did this idiot really think that after everything they'd been through, the wrong dessert or a scratchy sweater could possibly threaten their relationship?
When Michael came home, he was met with a horrifying sight. Yoichi was sitting on the living-room couch, leisurely sipping tea from the red mug while flipping through the precious secret notebook. Their eyes met. One gaze was calm and quietly accusatory. The other was full of panic and shame. Kaiser had no idea what kind of reaction to expect. But carefree laughter, followed immediately by a kiss, certainly wasn't it.
“You know,” Yoichi said, “you could've just asked me.”
“I...”
Completely at a loss, Michael blurted out the first thing that came to mind.
“Your rival isn't supposed to know what you know about him.”
It was the principle they'd both lived by on the field. Yoichi burst into laughter again before handing the notebook back.
“Well then... keep gathering information, my rival.”
With that, he walked out of the room, leaving Kaiser alone with what were no longer his secrets—and with an overwhelming sense of embarrassment. Absentmindedly, Michael flipped through the pages one after another until he suddenly stopped. There was a new entry. One he definitely hadn't written. The handwriting was different.
After reading the single line, he couldn't hold back a relieved smile.
"Don't put Yoichi's things on the top shelf."