In theory, Hinata knows all about the philosophy of Occam’s razor.
Kenma had explained it to him before when the two of them were watching a true crime documentary one night. After they had debated endlessly on who they believed to be the real culprit in a particularly grisly case, Hinata had finally felt like he hit the nail on the head.
“What if the police are framing the main suspect?” Hinata asked, eyes wide as he clutched the bowl of popcorn in his hands like a shield between him and the television.
“Why do you think that?” Kenma asked, his tone amused as he glanced at him from the corner of his eye.
“Because!” Hinata began excitedly, leaning forward to explain his hypothesis, “In their testimonials, all the officers were acting super shady. The police were clearly under a lot of pressure for the case, so they chose the most likely suspect and made sure their evidence pointed toward him!”
“Hmm. That’s a stretch.”
“What?” Hinata gasped, looking offended, “No way! It’s totally believable!”
“When it comes to things like this, the rule of thumb is that the most simple answer is usually the right one,” Kenma informed him with a shrug of his shoulders. “That’s Occam’s razor.”
“Huh? Occa-what? What do you mean?” Hinata cocked his head to the side and scratched at his chin in confusion.
“Well, you’re making too many assumptions,” Kenma clarified, picking up the remote to pause the documentary, “The real murderer is probably the boyfriend. He was the last one to be seen with her, and he had the best motive. It’s the most likely explanation.”
Hinata furrowed his brows as he considered his friend's statement.
“But that’s so ...boring!"
His response earned him a small chuckle from the boy beside him.
“It’s a true crime documentary, not a thrilling mystery drama, Shouyou.”
While at the time, Hinata had only pouted and insisted they watch the rest of the documentary so he could further build his case with Kenma rolling his eyes fondly and unpausing the film to appease him, when he thinks about it later as he's laying in bed and responding to texts on his phone, he realizes that the concept really does make sense.
The most likely answer is usually the simplest one.
Hinata puts it in layman's terms for himself.
If one day, Kageyama is late to practice one morning, is it most likely that he has A) missed the bus and had to catch the later one, B) went off to chase after his neighbor’s cat and got lost, or C) been unexpectedly abducted by aliens?
The answer is obviously A, Hinata is mostly sure of it, but he can’t help but wonder about the other options despite that.
What if Kageyama was chasing after a cat? Animals didn’t like him to begin with, so it was very possible. And there isn’t actually any proof that there aren’t aliens, so it didn’t make sense to cross that one off just yet.
And when he thinks about it this way, Hinata comes to the conclusion on his own that just because the answer is the simplest, that didn’t really mean it was the best one.
Because the best one had to be the more exciting one, right?
He sends this thought process in an almost nonsensical text to Kenma before drifting off to sleep, already dead to the world by the time his friend sends him a questioning response in turn.
But the truth is, Hinata doesn’t ever feel the necessity to apply the principle to his own life until much, much later.
It happens like this—
Oikawa is in the middle of his off-season, and rather than spending the month hanging around in Argentina, he decides to spend it back in Japan. It's on his third day back home that he calls up Hinata and asks him to dinner.
Hinata hears the smirk in the other man’s voice as clear as day over the telephone line as Oikawa says, "Well, remember that dinner you owe me?" And not one to relinquish the upper hand—not without putting up a fight anyway—Hinata flips the table on him and asks him if he wants to come over to his place instead.
The following weekend finds his former rival on the front steps of his apartment, hands full with bags of groceries and ready to prepare Hinata ‘the best homemade Argentinian meal of his life’, because apparently Oikawa is not the kind of guy that gets one-upped without a fight either.
They’re in the middle of a particularly riveting conversation about Oikawa’s last match abroad when they hear the rustle of keys—the sound of the front door opening and shutting rapidly.
Hinata looks up from his plate of homemade agnolotti—admittedly, yes, the best Argentinian meal of his life—to see Atsumu strolling in, gym bag thrown haphazardly over his shoulder, twirling his spare apartment key with his finger.
The blonde quirks a brow at the two, the corner of his lips curling into somewhere between a smirk and a sneer and Hinata is taken aback for a moment before he realizes that Atsumu isn't looking at him, but rather, the other man he’s seated across from.
On the other side of the dining table, Oikawa meets Atsumu’s stare straight-on with a haughty expression of his own to match, elbow on the table, with his chin resting almost too casually on his open palm. They seem to be measuring each other up, and Hinata either doesn’t notice or doesn’t pay any heed to the growing tension in the room.
“Hi, Atsumu-san!” Hinata greets cheerfully, voice bright enough to catch Atsumu’s attention, and it prompts the blonde’s eyes to slide away from Oikawa’s to meet his—the slanted smile on his face melting into something more genuine. “Hey, Shouyou-kun."
There's a short pause, and then Atsumu is shrugging the bag off of his shoulder. “I need to use yer shower."
Hinata nods his head in affirmation, oblivious to the disbelieving glance thrown his way from Oikawa at the seemingly normal request, and gestures to the bathroom with a wave of his hand.
“Towels are in the same place, and your change of clothing is clean and in the same drawer.”
“Thanks!” Atsumu responds, and he’s already moving past them, slipping off his shoes and setting his bag down in the foyer, all the while pointedly ignoring the glare directed at him from the brunette seated at the table.
When he disappears down the hallway, Hinata settles himself back in his seat and looks up in surprise to meet Oikawa’s trademark pout, complete with furrowed brows and an upturned bottom lip.
“What?” Hinata asks, blinking back at him. Oikawa lets out a loud, dramatic sigh, slouching back in his seat as he stares back at him with a sulky expression.
“Nothing, Shouyou, nothing at all.”
Hinata waits a moment—because the moping always only takes just a few seconds really—before Oikawa is leaning forward again, sliding his half-eaten plate of food to the side as his expression morphs into something more irksome.
“I just find it very interesting how comfortable Miya seems to be around your place,” the brunette finally says, his fingers drumming rhythmically against the wood of the table as Hinata tilts his head to the side curiously.
“What do you mean?”
“Like the fact that he just so happens to have the keys to your apartment?” Oikawa questions, lifting his brow. “Or that he feels so comfortable to drop by to take a shower even though, I’m sure, there is a perfectly functional shower in the gym he probably just came from.”
Hinata is still staring at him blankly, and Oikawa leans further across the table, clearly miffed at the other man’s indifference.
“Really? I mean...the drawer ? Do I have to explain how that looks?”
“Oh,” Hinata says simply, because he doesn’t quite know how else to respond to that. He supposes that it must look a bit odd from Oikawa’s perspective, given how comfortable Atsumu appears to be at his apartment.
While his teammate might have had his own place closer to the city, he was somehow still always there—filling up Hinata’s space with his raucous laughter and playful grins, shoving in close to him on the couch when they were watching a movie, even though there was clearly enough room on Hinata’s nicely upholstered sectional for the other man to spread out more comfortably.
“Yeah, he’s here a lot,” Hinata clarifies for good measure, and there’s a noticeable twitch in Oikawa’s brow as he levels the smaller man with an appraising look.
“A lot, huh?”
“Yeah, I mean...he’s like one of my best friends,” Hinata says—and huh, had he ever actually admitted those words out loud before?—before he’s shrugging his shoulders and smiling again.
“So, of course he’s here a lot.”
Oikawa gives him a flat you’re kidding me, right look before he huffs to himself and pulls his plate back toward him, poking almost aggressively at his pasta with his fork. The sound of the metal grating against the porcelain causes Hinata to outwardly wince in turn.
Hinata is about to open his mouth to question the other man’s odd behavior, when Atsumu reappears again in the living room entrance, barefoot and toweling his damp hair. The old practice shirt he is wearing is old and soft enough that it stretches across his shoulders comfortably, and Hinata finds himself staring for just a moment too long because Oikawa is suddenly clearing his throat loud enough to call his attention back to him.
“You staying for dinner, Atsumu-chan?” Oikawa asks in a sing-song voice, though when Hinata turns to look at him, the other man's expression is sharp and considering. It's clearly a challenge.
“Not sure if the invitation was extended, Tooru-kun,” Atsumu says, voice just as sickly sweet.
And if Hinata wasn’t aware of the tension before, he was most definitely aware of it now, feeling more than a bit awkward as the two men continued to size each other up from across the room.
“I suppose you can have some of the extras still on the stove,” Oikawa says, giving the blonde a considering once-over from the corner of his eyes, “Since you seem to be in the habit of bumming off of others to begin with.”
Hinata feels his jaw drop at the now open cattiness, and he quickly turns to Atsumu, apology ready on the tip of his tongue, when he’s caught off guard by the shit-eating smirk on the blonde’s face, razor-sharp as though he were on the court speaking to a rival and not standing barefoot in Hinata’s living room and staring down his dinner guest.
“Oh, well I guess I’m just so used to hangin’ ‘round here,” Atsumu replies, tone deceptively light as he saunters around the table and settles himself behind Hinata, slinging his arm over the smaller man’s shoulder. "It's basically home, ya see."
Hinata catches Oikawa narrowing his eyes at the appendage draped over his body as though personally offended by it before lifting his gaze to meet Atsumu’s, maintaining the lofty expression on his face as he does so.
“Only because Shou-chan is probably too polite to ask you to leave.”
“I think Shouyou-kun is perfectly capable of telling me that himself, don’t ya think?”
Hinata frowns at both of them, because he suddenly feels as though his name being thrown around is becoming more of a mark of territory rather than a term for endearment, and he doesn’t really feel like having to referee a pissing match in the middle of his apartment.
“Are you two going to play nice or do I have to kick you both out?” Hinata finally questions, mustering up the most unimpressed look that he can manage.
The two promptly shut up at that, and Atsumu finally detaches himself from Hinata’s shoulder to plop down into the empty seat next to him at the table. Still watching the two of them suspiciously, as though waiting for them to start up one more, Hinata is satiated when the two seem content to merely ignore one another for the time being. He slides his half-eaten plate of food over to the blonde beside him, and Atsumu purses his lips for a moment, before reluctantly picking up the fork and digging in.
Placated for the time being, Hinata turns back to Oikawa with an easy grin, winking at him.
“So, Oikawa-san was just telling me about this killer set he did in his last match,” Hinata says, lightly nudging the blonde man next to him.
Atsumu pauses with the fork half-way in his mouth and spares the man across from them a severely disinterested look. "Is that right?"
"Yep," Hinata responds, eyes gleaming, "Why don't you finish telling the story, Oikawa-san?"
Oikawa is quiet for a moment, looking between the two of them with a speculative glint in his eye, before he makes the decision to appease Hinata, launching into a play-by-play of the match as prompted. There's still hints of the pout evident in Oikawa's tone as he speaks, but it helps that there is no hiding the interested spark in Atsumu's eyes as he unconsciously leans forward over the table to listen to the story better.
Hinata observes all of this and only smiles complacently in between them, biting on the inside of his cheek to keep his amusement in check so as to not ruin the moment.
“So, Shouyou, you gotta tell us,” Bokuto says at their weekly Jackals dinner, leaning over to the side as his voice turns mischievous, “Are you dating Oikawa or Atsumu?”
Hinata almost spits out the water he’s drinking, grateful that the aforementioned teammate had just ducked out to use the restroom not moments ago.
“See, we’re kinda split down the middle,” Inunaki reasons, sidling in beside Bokuto in the booth and holding both of his hands up demonstratively, “On one hand, we sort of always suspected that you and Miya were, you know. ” He raises his eyebrows up and down suggestively, causing Hinata to shoot the man a disbelieving look.
“But then on the other,” Adriah cuts in with a grin on the other side of the table, “We never knew about you and that Argentinian player, either.”
“Yeah, when were you going to own up to that one, Shouyou?” Bokuto says, grinning unabashedly. And the other man has an almost proud gleam in his eye, or maybe Hinata was just imagining it.
“Uh, well, you see, I’m not...” Hinata finds himself trailing off, suddenly at a loss for words.
“...Dating either,” Hinata clarifies with a definitive shake of his head.
At that, everyone gives him an incredulous look, and even Sakusa is staring back at him with narrowed eyes from the corner of the table.
“O-kay,” Inunaki says slowly, blinking at him, clearly not expecting that answer.
“You’re not dating either of them?” Barnes echoes in confusion, and Hinata can only nod his head in confirmation, not willing himself to speak just yet.
“Do they know that?” Sakusa asks, and apparently that’s the question of the hour, because suddenly everyone’s staring at him expectantly as if this isn’t something he just started considering at that very moment.
Before Hinata can attempt to formulate an answer, Atsumu is back and sliding into the booth next to him, so close that their knees bump together as he throws an arm over his shoulder with a slight smirk. “Miss me?”
And then blinking dumbly to himself, Hinata starts to wonder, too.
He finally gets his moment of clarity not too long later.
Hinata spent his day-off helping Takeda-sensei and Coach Ukai at their new Karasuno training camp, and when he finally gets home quite late into the evening, he collapses onto his couch, exhausted, feeling his stomach grumble in protest at being ignored. He knows that he should probably get up and make a trip to the nearby market to pick up some much-needed groceries, but he can't help the heaviness in his eyes as they begin to drift close.
He tells himself that it's just one nap, and he rarely if ever takes advantage of those so he totally deserves it, and tucking his cold feet underneath one of the couch cushions, Hinata closes his eyes and lets the tiredness take over.
Voices pull him from sleep some time later. At first he ignores them in favor of getting a few more minutes of rest in, but eventually Hinata stirs, eyelids fluttering open as he registers just who exactly is in his kitchen.
“Ya think that’s enough food?” Atsumu’s voice is doubtful as he peers over Oikawa’s shoulder. “Shouyou-kun eats a lot, ya know.”
There’s a sound of Oikawa scoffing back in turn. “I think I happen to know how much Shou-chan can eat, thank you very much.”
Hinata pushes himself up and stares stupidly at the blanket that falls off of his shoulders to pool around in his lap—had he put that there?—before turning slightly towards the kitchen and sees that the space has been invaded by two softly bickering men.
“Are ya sure yer even cookin’ it right?”
“I’m sure. Hands off!”
Still groggy, Hinata frowns at them from over the side of the couch. “Atsumu-san? Oikawa-san?"
"...What are you two doing in my kitchen?”
They both freeze at the sound of his voice, and Atsumu is first to recover, shooting him a lopsided grin as he waves a spatula at him in greeting. “We’re cooking dinner for ya, of course.”
“Dinner?” Hinata echoes hopefully, feeling his stomach grumble in response.
Oikawa clicks his tongue in a disapproving manner at that, resting a hand on his hip as he gives Hinata a concerned once-over from where he leaned over the back of the couch. “You sounded so tired on the phone when I called earlier. I suspected there would be a chance you'd skip dinner."
"Plus we knew ya didn’t have any food in yer fridge," Atsumu cuts in from beside him with a shrug.
For a moment, Hinata wonders if he's still asleep. “You did?”
“‘Course, silly,” Oikawa responds with a slight laugh, “We were just over the other day.”
“Oh.” Hinata stares at them blankly for a moment, thinking back to only two days ago when they had held a movie night at his apartment. He remembered being sandwiched between the two setters as they fought over the choice in movie, finally settling on a recently released action-packed blockbuster.
“Well, I am starving," Hinata finally admits, beaming gratefully at them from where he was seated, "So, thank you guys.”
Atsumu and Oikawa seem to noticeably soften at that, and Hinata stretches his arms over his head, letting out a small, stifled yawn, before shoving the blanket off of his lap and walking over to see what they were cooking.
Hinata's running a hand through his hair when he finally settles himself next to them, eyes brightening when he sees what they’re preparing. “You’re making egg over rice?”
“Well, it is your favorite,” Oikawa says with an appreciative grin, coming up behind him to sling an arm comfortably around his shoulders. Hinata leans against his frame easily, missing the way that Atsumu seems to stare pointedly at their positioning in front of him as if saying hello, that’s my move.
“We made ya some other stuff, too,” Atsumu says, still looking put-out, and Hinata scoots out from under Oikawa’s arm to peer around the blonde’s shoulder as he sets the food down on the table in front of them. His mouth waters in appreciation.
As the the three of them settle down at the table and dig into the meal in front of them, the conversation flows surprisingly easily given the disaster first dinner they experienced together all those weeks ago. Hinata tells them about the new bright-eyed Karasuno team and how much they reminded him of himself when he was younger. Oikawa is smiling as he reflects on how much they had grown since then—because remember that time he threatened him outside the bathrooms at Interhigh?—and Atsumu wonders aloud what would have happened if Seijoh had ever made it to Nationals.
"If Oikawa's team had made it to Nationals, then that would mean that you and I would never have gotten to meet," Hinata realizes with a frown, stacking the empty bowls on the table on top of each other.
"Ah, so I must have made quite the impression on you back then, huh?" Atsumu responds smugly, taking the stack of dishes off of his hands and heading to the sink.
"Well, that's when you promised you would toss to me one day, remember?" Hinata says, as though it is the most obvious reasoning in the world.
Even Oikawa looks impressed at that, letting out a low whistle under his breath. "That's quite a declaration coming from a setter like yourself."
"Yeah, and I meant it, didn't I?" Came the cheeky response from the kitchen, and Atsumu appears back in the living room just a moment later, still wearing the same self-satisfied look on his face. "Ya never got to set for Shouyou-kun, huh? Not in a real match, anyway."
Oikawa's expression morphs into one of horror as he looks from Atsumu and back to Hinata with wide eyes. "I haven't."
"It's not too late," Hinata says with a laugh, and Atsumu tries his best to look affronted.
"Ya wouldn't leave me for Argentina, would ya, Shouyou-kun?"
And it's Oikawa's turn to look smug when Hinata actually looks thoughtful at the question. The two of them laugh at the blonde's expense when he sputters at them indignantly in turn.
It's when they are getting ready to leave and Atsumu turns to ruffle Hinata's hair affectionately, hand lightly cupping the side of his cheek before stepping out the front door, and Oikawa comes up behind him to press a kiss casually on the top of his head that he finally realizes it.
He tries to think about it rationally in his head.
If Hinata suddenly found himself faced with the possibility that he was unknowingly dating one of his friends, was he A) leading Atsumu on, B) leading Oikawa on, or C) somehow dating them both?
The most simple answer is usually the right one, Hinata reminds himself, mind turning over the possibilities but feeling no close to finding the right answer.
Because truthfully, there was nothing simple about it. None of the possibilities seemed very likely.
What if he was dating Oikawa? Was that why the other man had chosen to spend almost his entire month off with him? Time off was something rare and precious for a professional athlete, so the very idea that Oikawa would choose to spend it with him had to mean something, right? But what if he was actually dating Atsumu? Is that why his teammate was always over at his apartment? And now that he thought about it, that sort of made sense, too. During and outside of practice, his teammate had become a constant presence at his side. The fact that the other man would basically follow him home every day, easing himself into Hinata’s space like he owned it was probably indication enough.
Which then led him to the last option, that somehow he was dating both of them.
And there was no possible way that that could be the simplest, most likely answer out of the bunch.
But then Hinata remembers his own reasoning, that just because the answer is the simplest, that didn’t really mean it was the best one.
Because the best one had to be the more exciting one, right?
Hinata is standing there in his doorway watching the two men walk down the hall together and already hearing the sounds of them bickering over whether to share a cab when he thinks, Oh, I’m probably dating them both.
He wonders if they’ve even caught on yet.