The Difference Between a Chuunin and a Jounin
Mirror and Image
The most noticeable difference between a chuunin and a jounin is the level of awareness. When comparing the two in other attributes; taijutsu, chakra levels, stamina, chakra control, or other little details and statistics, chuunin and jounin were remarkably balanced. The critical classification between the two was the level of jutsu that said nin could perform. While there was the occasional chuunin that knew an A-ranked jutsu, and while all chuunin were more than capable of learning high rank jutsu, the reason they remained chuunin was because they could not handle the jutsu in combat because of the level of awareness. B-ranked jutsu and higher had a minimum of fifteen seals to work through, intricate chakra patterns to mold, and frankly required an enormous amount of concentration.
The divide, therefore, between chuunin and jounin came when the nin needed to not only maintain the level of concentration for the high rank jutsu, but also maintain that level of concentration on the world around them in order to use the jutsu appropriately and/or modify accordingly.
The difference between a jounin and Hatake Kakashi was that he had the jounin's level of awareness and a genius mind that worked quicker than most; he was simply a different class of nin. He could see underneath the underneath.
Perhaps the perfect example of this came one day in the mission room. He had been waiting in line to get his most recent list of genin to test - and most likely fail. He had been in the hospital beforehand, in surgery when the Scroll of Forbidden Seals had been stolen by one Uzumaki Naruto. Not much had been said on the incident, Sandaime only said that a chuunin had convinced Naruto to return the Scroll, and that another chuunin had incited the theft to begin with. Kakashi had pressed at first, Naruto was a connection to his sensei, and Kakashi couldn't quite let that go. Sandaime had gotten tightlipped, however, and Kakashi knew not to press; he respected the Professor's adherence to privacy, and his proclivity to protecting his ninja.
The topic had been, effectively, all but forgotten by Kakashi as something he would either learn later or not, and so he was waiting in line for his assignment.
With one person in line in front of him, Kakashi reading his book, the chuunin at the desk moved to stretch and winced fiercely. The shinobi in front of Kakashi tilted his head, giving the Copy Nin a view of a man with a scar over the bridge of his nose. "Jeez, Iruka, are you okay?" the chuunin in front asked.
"Yeah," Iruka said, rolling his shoulders and hunching slightly before straightening.
"... Mission," Iruka said, handing off the scroll.
Chuunin, with their level of awareness, accepted it and moved on. Jounin, with their level of awareness, knew that it was a lie and didn't press. Kakashi, however, as he stepped forward and waited for his scroll, thought about the lie, thought about how chuunin were often relegated to desk-jockeys and administrative duties, meaning that a mission that created the level of injury that made comment from others rare, and coupled the little factoid with the fact that Iruka was rumored to be an academy teacher - one of Sandaime's favored. This lead to the connection to the Professor's protective streak and the recent incident with the Forbidden Seal Scroll, and then lead to Kakashi assessing Iruka's injury more astutely. Then it all crashed together in his head.
"Oh," he said, slightly surprised. "That was you."
Everyone blinked - first that Kakashi had initiated anything resembling conversation, but moreover that he had acknowledged Iruka in the manner that he had.
Even the chuunin was staring, looking up to Kakashi and wondering what on earth he had done to garner the elite jounin's attention.
The Copy nin leaned forward slightly, his sleepy-looking eye darting up and down Iruka as if inspecting him. Finally, he nodded his head, as if acknowledging something. "You do good work," he said.
Shocked, mute, and a dangerous mix of dazed and stunned, Iruka could only hand the elite jounin a scroll after a confused, muddled nod.
Kakashi only shrugged his shoulders and took the scroll, walking off as if nothing momentous had happened.
The rest of the Konoha nin were not so lackadaisical.
As one, everyone in the room demanded, "What the hell did you do, Iruka?"
This was followed with things like,
"Were you on a mission with him?"
"Did you save him or something?"
"Did you take the jounin exam and not tell anyone?"
"When did you get to be so chummy with Sharingan no Kakashi?"
"As the personal interest of my Eternal Rival I challenge you to a match of Flower Arrangement!"
The rest of the day was shot all to hell after that.
Kakashi, for his part, suffered similar exclamations.
Curiously, however, it was not filled with interrogation or accusations but rather confused bewilderment:
"How do you know that chuunin?"
"Do you owe him a favor or something?"
"What kind of chuunin makes you say he does good work?"
"He's just a chuunin! What do you see in him?"
Where Iruka was left flustered and confused and still in pain from his recent adventure, sputtering and trying to be invisible again and determined to find out who the hell was this guy who just disrupted his life, Kakashi was left staring at the menagerie of jounin and wondering what was wrong with them.
" 'Just a chuunin'?" he asked.
"Well, yeah. He's just a chuunin, so what'd he do to get your attention?"
See, where chuunin saw the event in the mission room as a chance to gossip or fantasize or generally get entertainment, jounin saw an enormous stratification of abilities, social circles, mission brackets, and frankly no way for the two to even know each other. Kakashi saw even further however, and became increasingly perturbed that the jounin had become so arrogant as to think of chuunin as "just" chuunin. It wasn't that he didn't also suffer from arrogance - the price of intelligence was the latent understanding that one was usually right; but the difference between jounin and Kakashi was that he learned - the hard way - that even the weakest member of a team could and would out-perform the strongest. Obito burned in his mind and he was tempted to give a piece of his mind.
Kakashi did, however, respect Sandaime's silent decision to protect Iruka's privacy, and he respected Iruka's desire to not talk about the incident, and he understood that there were probably a lot of complicated emotions associated with fighting a traitorous chuunin and saving Naruto. And so he simply shrugged his shoulders.
"He's a Konoha ninja. Of course he does good work," he replied.
Author's Notes: In a fit of insanity I've been lurking around Naruto fanfiction looking for good Kakashi fanfiction that I haven't read already. I fear it doesn't exist, and so I decided to write some myself. Meh. Anyway, hope you like!