Sasuke was really clever, there was a reason he was heralded as a genius. However his ninja ability didn't matter to Naruto so much as his ability to explain complex mathematics. If Naruto hadn't thought of Sasuke as his best friend before his help, there was no doubt in his mind now. Naruto was sure that he was Sasuke's best friend as well if only because Sasuke didn't really have any other friends. Shino might have counted, but Naruto couldn't really tell as all that passed in between Shino and Sasuke were grunts and occasional words when they were excited.
While Sasuke may have seemed calm and collected to those around him, the Uchiha massacre still weighed heavily on him. Occasionally he and Naruto would get talking and Sasuke would forget himself, mentioning his brother. That was all it took for him to pale suddenly and shut his mouth, refusing to talk for the rest of the day. Naruto learned quickly though, he learned not to bring up family, not to bring up abilities he had learned outside of the academy and he had learned not to utter the word revenge because for Sasuke it was a word that could make him angry and miserable for a full week.
Revenge was still always in his mind, but it played background to everything else though. His efforts in his training were redoubled compared to before, making his past efforts seem lazy in comparison, and although he missed a good month of work he was caught up in only a few days. Only, due to his being the best student in the class by great lengths he didn't have anyone to spar with that could stand up to him, so Naruto became his sparring partner slash training dummy, if only because he knew that Naruto could take it. So the deal became that Naruto would help Sasuke with his training while Sasuke would help Naruto with his sealing.
Neither of them were comfortable enough with jutsu to use them in a fight, although their fears were very different and so their combat matches were mostly either taijutsu with an occasional bit of kenjutsu. Kunai and shuriken were allowed but they couldn't be aimed lethally, after all they weren't trying to kill each other. At least that's how Naruto felt, sometimes it was hard to tell if Sasuke felt the same way.
On a day a few months after Naruto's eighth birthday, the two of them were standing off against each other on the roof of the orphanage, each of them waiting for the other to make the first move. It was agreed that no projectile weapons were allowed when practicing on the roof after someone had almost been killed by a stray shuriken. Thankfully they had been a jonin and thus was able to catch the weapon easily if a bit annoyed. In general their matches required different rules due to each other's strengths and weaknesses just to balance out the odds. For Naruto to win he only needed to draw first blood, but for Sasuke to win he needed to either knock Naruto off the roof or put him in a position where a killing move would be possible if not viable.
This match, like far too many of their matches, started with a staring contest, trying to gauge for weaknesses and find an opening, seeing as Naruto had no hope of catching Sasuke if he wasn't distracted and Sasuke needed to make his hits count.
Sasuke sighed, keeping his eyes on Naruto. "I guess we're doing this again. There's a ramen bowl behind you," he said.
Naruto growled. "I'm not going to fall for that one again. We're on a roof, why would there be ramen?"
"I put it there," Sasuke deadpanned.
Naruto grinned. "Nice try, but I already looked just to make sure."
Sasuke smirked. "I knew you would look. That's why I put it under a henge."
Naruto's smile froze. "You knew I would look?"
Sasuke nodded slightly.
Naruto frowned. "You're just trying to distract me. I know you wouldn't bring ramen all the way up to the roof. Besides I've been with you all day, when would you have gone to get ramen?"
Sasuke grinned. "You got me. There's no ramen. It's just my backpack. There's no ramen behind you at all."
"See I told you," Naruto said gesturing behind him and in doing so dropping his guard for an instant.
An instant was all that Sasuke needed. In that moment Sasuke darted forward, drawing a kunai and stabbing straight for Naruto's stomach. Turning his eyes back to Sasuke, Naruto let out a surprised yelp and barely managed to raise a kunai of his own to deflect the attack. The attack had been a feint however and where Sasuke's kunai should have been was nothing but air. Sasuke's shoulder crashed into Naruto's arm and he Sasuke pivoted, using his momentum and his angle of attack to spin around Naruto and shove his kunai at Naruto's back. Shoving an elbow back, Naruto managed to shove Sasuke away, forcing his kunai to miss, following that with a handspring forward where he gained enough distance to reorient himself. As he faced Sasuke he had already crossed the distance between them, his mouth drawn up in a line of concentration. Growling, Naruto backed away, trying to create some space between the two of them. For the second time that day he let out a loud yelp at the feeling of wire pulling taut behind his legs and as he fell he could see Sasuke smirk. With a small hop Sasuke landed on Naruto's stomach, knocking the wind out of him and he quickly put his arm in a lock to prevent him from getting up.
"Tap out," Sasuke commanded. "You can't forget about traps in every battle," he added.
Naruto growled and strained against the grip. "You forgot about my trap," Naruto countered while straining against the lock.
Sasuke raised an eyebrow. "What trap? You can't do anything. I've already won."
"You forgot about this," Naruto shouted, shoving his other hand forward, kunai outstretched.
In a panicked state, Sasuke stiffened and then,
'Crack!'
Sasuke let go of the arm immediately but it was too late and Naruto howled in pain, cradling his arm. Moving over to Naruto Sasuke looked him over. "I'm sorry. I didn't mean. . .it wasn't. . .,"
Naruto chuckled through the tears of pain. "Noth. . .ow. . .nothing to worry about, idiot. I'll be better tomorrow."
Sasuke looked at him skeptically. "I'm going to call a medic, don't go anywhere."
"I wasn't planning on it," Naruto said through clenched teeth but his words fell on empty ears as Sasuke was already gone, running down the stairs and calling out for help.
Naruto could already feel his body trying to knit the bones together but he didn't want the bone to set wrong and he couldn't wait for however long it would take for a medic to arrive. "This is going to hurt," he mumbled to himself before using his functional arm to grab the broken limb and position it correctly. It felt like hundreds of hot needles entering his flesh with each movement. He may have blacked out in the middle for a few seconds but it was finally done and he laid his arm on the ground hoping that he wouldn't have to move it anytime soon. Looking at his arm with a sense of nausea he was suddenly thankful that he hadn't eaten yet. Panting, he let his head down to the roof and closed his eyes.
When he woke up again he was in a hospital bed and his arm in a cast. Looking next to his bed he could make out Sasuke with his head bowed sitting next to Naruto's bed.
"Sasuke," he said, prompting Sasuke's head to dart up in terror. It took a few moments for him to realize where he was and who he was talking to, letting out a small groan upon seeing Naruto. "Are you feeling alright?" Naruto asked worriedly.
Sasuke smirked. "Did I hit your head as well? You're the one with a broken arm."
Naruto waved him away with his free arm. "This is nothing. You don't look like you're doing so well though."
Sasuke met his eyes and eventually turned away. "I've made a," he paused. ". . .decision. I don't think we should spar together. You're good, but I don't want to kill you. And after today. . ." he trailed off.
Naruto snorted. "Stop acting like it's the end of the world. It's just a broken arm and you didn't mean it. Just watch, I'll be back tomorrow and I'll whup your butt."
Sasuke squinted at Naruto. "There's no way I'm fighting you with a broken arm."
"Duh. That's why I said tomorrow."
"Have you ever had a broken limb before?" Sasuke asked, changing tack.
Naruto shook his head.
"Well broken limbs normally take a full month to heal at least and even then there's a lot of therapy just to be able to use it again," Sasuke explained.
Naruto's face scrunched up. "Why does it take a whole month?"
"It just takes a month, idiot."
Naruto shrugged. "Well I don't want it to take a month, so I'll be better tomorrow, ok?"
Sasuke palmed his face. "That's not how it works. Actually you know what. How about we see tomorrow. If you can fight me I'll buy you a bowl of ramen."
Naruto smirked. "Three bowls."
"Fine. But if you can't then when you recover you have to carry my backpack to the academy for a month," Sasuke said.
Naruto nodded. "Deal."
The rest of the day was spent with Sasuke trying to explain their homework. It had taken him a while to get it through Naruto's thick skull but after some time a lot of things managed to stick. People just didn't understand that to explain something to Naruto it had to be associated with something he was interested in. Comparing chakra to food and sealing only went so far though and if the associations didn't work there were always threats which were much more effective. With Sasuke's help Naruto's grades had shifted into the middle average of their class, if only because Sasuke refused to train with a dead last. After all he had a reputation to uphold.
For Sasuke returning to the hospital the next day was an experience in mixed emotions. On the one hand he didn't like the fact that Naruto still had a broken arm, especially as it was his fault, however on the other hand he couldn't wait to rub it into his face.
He had arrived early seeing as they needed to go to the academy and they always went to the academy together, broken arm or no. Waking Naruto was a lesson in futility but he came around eventually when Sasuke dropped some cold water from his pack into Naruto's ear making him cry out.
"What's wrong with you?" Naruto growled, sitting up immediately with the closest expression to anger that he was able to hold.
Sasuke grunted, putting his bottle away. "Get dressed, we're going to be late."
Naruto growled again but complied, pulling off his clothes from the previous day and pulling on clean ones with one hand, all with the practiced efficiency of having done so before.
"Do you normally dress yourself with one hand?" Sasuke asked.
Naruto nodded. "My sealing teacher told me to get used to doing things with only one hand because I never know when I'm going to need the other to start making a seal, so every day I only use one hand for stuff. Luckily today is the right hand otherwise I wouldn't be able to do anything."
Sasuke blanched, memories flashing into his mind that suddenly made a lot of sense. Trying hard not to be infected by Naruto's morning optimism he leaped out of the window, only pausing to make sure that Naruto was following. Then he was leaping towards the wall of a house, pushing off again upon contact to land on the roof, Naruto following if only a little slower.
"I guess you'll be carrying my backpack for a month," Sasuke said, jumping forward.
Naruto jumped after him chuckling. "We'll see."
Sasuke frowned before shrugging mentally. If he wanted to play it that way then fine, he would just have to show him how useless he was later. There was no way Naruto could put up a fight with his whole left side being taken up by a heavy cast.
Naruto didn't think that he'd ever been fawned over but the girls in class saw his cast and thought that today was get to know Naruto Uzumaki day. He couldn't very well say that Sasuke broke his arm though so he had to tell everyone that he had been doing something stupid which disappointed the general populous. It was almost a pity when most of the girls decided to file away from him after hearing his convoluted excuses, although the story did seem to attract the attention of all of his regular acquaintances. Sasuke chose to sit on the sidelines however. When asked about why he avoided making friends he told Naruto that he couldn't afford to get distracted from his goal. Naruto hadn't pushed the subject. That didn't stop him from trying to include Sasuke if he was able, kind of like Shikamaru and Choji only that Choji wanted to be included. Although Naruto heavily suspected that Sasuke wanted to be included as well but felt it a betrayal of his goal to play a game when he could be training. Sasuke tended to be in a foul mood during their breaks, however that day his face only wore a smirk.
Jumping from rooftops back to the orphanage after classes had ended, Naruto diverted from the usual route, heading instead to one of the emptier training grounds.
"Idiot. What are you doing?" Sasuke called after him.
Naruto looked back confusedly. "We're sparring, aren't we?"
Sasuke shook his head, stopping on someone's boiler. "No. Your arm's broken. You can't fight."
Naruto scratched his head. "That wasn't the deal. We agreed if I couldn't fight you would win, but I can fight. In fact I'm gonna win this time, you won't even see it coming."
Sasuke's smirk stiffened. "I'm not hurting a cripple."
"Sounds like you're scared," Naruto teased.
Sasuke mouth tightened to a slit. "If you want to play it that way then fine. But if I feel that you're not putting up a good enough fight I'm stopping and you lose."
Naruto nodded, turning away quickly and returning to his previous route.
In the training field and they were once again facing off, Naruto favoring his one side in light of the injury. Sasuke may have been inclined not to take Naruto seriously but having sparred with him for several months he knew that Naruto was good at pulling out a surprise at the most unexpected of times.
Naruto shifted his arm and winced, blinking momentarily. It was enough. Sasuke threw two shuriken following up with a kick for wherever Naruto dodged to. Only he didn't dodge. Instead, Naruto brought his left arm up and caught both shuriken in his cast, then striking out with his other arm he almost hit Sasuke, forcing him to reassert himself in midair and land in an awkward position. Then Naruto was coming at Sasuke with a strike of his own, kunai drawn and aiming for his torso. In a panic, Sasuke threw his kunai up in between his legs, forcing Naruto to back off for a moment. Pivoting on the spot, he spun around and slammed fist after fist into Naruto's stomach. Two, then five, then ten before Naruto was able to bring in a counter attack and by then he was very clearly hurting. Sasuke backed away from the counterattack and pulled on a wire he had slipped around Naruto's wrist, forcing him to kilter off balance with his punch, then bringing his own fist up straight for Naruto's jaw. There was no question about it, he was going to knock Naruto into the next day. There was no way Naruto could escape from this.
Naruto's left hand, caught Sasuke's fist, grinding his attack to a halt. Sasuke didn't even have time to react before Naruto's other hand poked Sasuke's fist with a kunai drawing a small amount of blood.
"First blood. I win," said Naruto, letting Sasuke's fist go when he was sure he wasn't about to receive another injury.
"How did you. . .?" Sasuke asked, absolutely flabbergasted.
Naruto looked at him curiously. "I told you that my arm would be healed today, but you didn't believe me so I thought I would use that as an advantage in our next fight. I think it worked perfectly."
Sasuke stared at him agape. "Your arm?" he asked. "It's fine?"
Naruto nodded, testing the joints of his now naked left arm. "Right as rain."
Sasuke groaned before letting himself fall onto his back. "That doesn't make any sense. Nobody heals that fast."
Naruto shrugged. "Are you sure about that?"
Sasuke tried to nod but realized quickly that he was lying down and nodding would hurt. "I broke my finger when I was four. I had to wear bandages around my hand for almost a month and even when it healed I wasn't able to use it properly for a few weeks afterwards."
"Maybe you just heal really slowly," Naruto suggested.
"No. I've seen others. We could go ask a doctor and I'm sure they would tell you not to take the cast off for at least another month," Sasuke said.
Naruto sat down next to Sasuke with a thoughtful expression. "I remember when I first joined the academy that everyone was complaining about how much they hurt after training. Do you think that had something to do with it?"
Sasuke considered it, then thought about it some more. "Maybe," he muttered before falling silent. "I changed my mind," he said, after a while.
Naruto frowned. "About what?"
"Training. But I want to up the game," Sasuke said, holding back a yawn. "Still the same rules for you, but you're not out of the match unless you're too injured to carry on. I can inflict any damage that you will recover from."
Naruto huffed. "I don't like it but fine."
"You're sure?" Sasuke asked brightening.
Naruto nodded from his place on the floor. "Yeah. We're going to be a team one day and I have to be able to keep up with you."
Sasuke grunted.
"Hey Sasuke."
"Hn."
"You owe me three bowls of ramen."
Sasuke groaned.
