Training with Hiroki-sensei was… exhausting. And a little demeaning. And a bit embarrassing.
"You're too skinny. You need to put on about 10 pounds in the next month. Don't worry, I'll give you a proper diet plan; all of that will be muscle."
"But, Sensei, I don't want to be a crazy, bulgy, gross…"
Sensei stared at her flatly until she trailed off, a trace of mirth in the eyes which were for some reason much more visible than they had been.
"Have you seen the Hokage? The strongest woman on earth? Does she look like some roided up muscle freak? No. Ninja don't get bulky or fat, unless they try, like the Akimichi. And they have to work at it. If you gain more than 10% body fat over the next 3 years, you'll be the envy of every Kunoichi in the village."
Sakura blinked at the assessment, and she realized he was completely correct. Ninja didn't bulk up, not really. At most they became sort of toned, but not like civilian body builders might. Shinobi were a breed apart.
And it was a good thing too, because they were to be up every morning at the crack of dawn and they worked themselves till the sun got too low in the sky for them to see what they were doing. But even that wasn't the end; it just meant they would go inside and turn on the lights so that Sensei could lecture them on chakra control and the more arcane points of shinobi theory.
Their instructor didn't waste time either; he started teaching on the very first day.
"As your instructor, it is my job to equip you with the tools you will need to face the challenges posed by shinobi life. None of these tools are deadly on their own, just like a kunai sitting on a table is not deadly on its own. A kunai is only as deadly as the hand which holds it, and that hand might be just as deadly empty, or while holding a sharp rock. A tool is a force amplifier, a method of bringing greater strength to bear on a problem. But it is only as useful as you make it."
Hiroki paused, checking to see that they were following his lecture. Sakura was sitting at attention, completely focused, but she could see that Sasuke seemed at least a little bit distracted, and Naruto didn't seem to be paying close attention either. Sensei frowned subtly, and the sky abruptly grew dark as his voice rang out with a terrible thunder.
"Knowledge is Power. Your mind is your greatest weapon, but like any tool it is useless if you don't keep it maintained. Understood?"
Team 7 startled in their seats to various degrees, with Naruto almost falling over in shock before the Jounin shrank back to normal and the sky brightened again. Satisfied with their attentiveness, their new Sensei continued.
"There are three core principles to success as a shinobi. Movement, Knowledge, Precision. The exact implementation varies from person to person based on personal style. For instance, for me-" -his arm blurred for a moment, sending a hail of kunai into the nearby target post- "Speed is King."
His arms folded behind his back as he gave each of them an intent look, eyes still in that oddly wide expression which made him look slightly surprised or shocked all the time.
"Speed is my strongest attribute, as it is for the majority of Sharingan users. The predictive powers of the doujutsu mean we are virtually guaranteed to win against anyone we can beat in a contest of quickness. So, speed is my greatest strength. However, Movement advantage can be obtained through many ways, such as the Sandaime Tsuchikage's flight ability, or even something as simple as a rebreather to allow you to swim underwater for long periods. Obtaining an optimum angle of attack, avoiding your enemy's attack, getting to the target before they do, or executing a tactical withdraw; all are reliant on your ability to move in a way your enemy cannot match, or in a way your enemy will not anticipate."
Sakura raised a hand eagerly, receiving a nod of recognition after a moment's pause.
"Is that what you meant by knowledge then? Using a technique your enemy doesn't know?"
Her sensei nodded slightly, but then shook his head in negation.
"It can be. However Knowledge, like Movement, has many ways of expressing itself. For instance, gaining a movement advantage could also mean limiting your opponent's ability to move with something like a kunai trap. Similarly, knowing an advanced jutsu is an advantage, but so is simply knowing the terrain of the battlefield better than your enemy does. Can anyone else think of a type of knowledge which could come in handy?"
"Oh! Oh! Knowing a cool jutsu to blow 'em away?"
Sakura wanted to hide her face at the blonde's inanity. Sensei just said that.
"That wasn't quite what I was thinking of Naruto. Sasuke?"
"Knowing your enemy's weak points."
Her beloved earned a small nod of approval. Naruto's hand was waving eagerly in the air again.
"Genjutsu!"
Sakura blinked in mild surprise. That... was a pretty good example, actually.
"Quite right Naruto. Just like controlling your enemy's ability to move is a good way to obtain an advantage in that arena, controlling what your enemy can see, hear, or think is an excellent method of obtaining a Knowledge advantage. Deception, or presenting a false image to your opponent so they misjudge your strength, is also a sound strategy."
Sensei's hand blurred once more, pinning a falling leaf to the tree trunk directly behind Naruto's head.
"The last was Precision. Again, this can take many forms. Throwing accuracy. Chakra control. My personal preference is for Seals. Fuinjutsu allows you to perform techniques which would normally require hundreds, or even thousands of hand seals."
The toned shoulders peeking out of the sleevless hood shrugged ambivalently.
"It's all about finding what fits you. The necessity should be obvious; a jutsu that can kill anyone it hits is useless if you can't hit the enemy."
"That's all general. You haven't actually talked about specific techniques."
Sakura glanced at the broody Uchiha prodigy sitting next to her, his hands folded in front of his mouth and his eyes set in their habitual glower, though he didn't seem particularly unhappy at the moment. Hiroki-sensei regarded his kinsman with an equal measure of cool detachment.
"Specific techniques would be wasted on all of you at this stage. You all require a much stronger foundation before you are ready to learn something more complicated."
Sensei shook his head slowly, gaze unwavering as a low breeze swept through the training ground, sending the scattered leaves swirling.
"Simply knowing a technique can lead to overconfidence. Overconfidence is a very common and often deadly flaw amongst high level Ninja. I received my S-ranking after killing Yamamoto of the Black Lightning, becoming the 34th ninja from Konoha to achieve that rank. That is the generally acceptable way to earn S-ranking; kill someone who is already acknowledged to be on that level. Yamamoto had made a copy of the Sandaime Raikage's signature technique, a hybrid Nin-Taijutsu that cloaks the user in a sheath of lightning to give them unparalleled speed and absurd striking power. The Raikage who perfected the technique was able to fight continuously for 17 hours without taking so much as a single injury, before he was crippled by fatigue. The story has grown over time; if someone tells you it was 3 days, they lie; no normal human, not even a Kage, would have the reserves necessary. Yamamoto believed the stories. He believed that so long as he could survive the enemy's first strike, he would be able to activate his technique and be assured of defeating his opponent before they could escape, even in the event of ambush. He should have listened closer to the tale."
A pale hand came up to tap gently at a point just below Hiroki's collarbone.
"The only practical way to penetrate the technique is using the technique. So I confused his ability to measure distance with a combination of 3 different D-rank Genjutsu and a few minor airborne poisons, and simply watched as he stabbed himself in the chest. He would have done well to master the basics more definitively. A house built on a shaky foundation will crumble in the first storm. Stamina, chakra control, and basic Taijutsu will be the foundation of your entire career; it will only give you larger returns the earlier you start."
A kunai appeared in his hand, flipping idly before disappearing just as suddenly to pin another falling leaf to the bullseye of the far target.
"Seize every advantage. While something as simple as a kunai is unlikely to be the thing which wins a battle, its absence might be the thing which ensures your loss. That's not to say I won't give you something more advanced once you can demonstrate that you have constructed that solid foundation."
Hiroki unzipped his flack jacket and the sweater beneath it, pulling the clothing open to reveal his torso. Sakura blushed a little at how toned the Jounin's muscles were, then blinked in surprise at the extensive network of tattoos across their Sensei's chest. She tentatively raised a hand as she noticed something odd.
"Sensei? What are the spots on top of your gates?"
When they were honest, Sensei's smiles were very nice, though faint and fleeting.
"Very good Sakura-chan. Naruto-kun, Sasuke-kun, pay attention. The body has a secondary circulatory system to control the flow of chakra. There are Eight Gates along that network which limit the flow of chakra for your own safety. Opening the gates is one of the ultimate Taijutsu techniques, but is labeled forbidden for the extreme strain that it places on the body. Opening all Eight Gates is almost invariably fatal. In this case, the Seals I have placed on all Eight Gates, including the two on the head though those are concealed by my hair, serve to aid in chakra storage. My reserves are slightly smaller than average for a shinobi of my level, a trait I inherited from my father, regrettably. There are exercises to increase your capacity, and we will be starting you on that soon, but beyond that the best way to build your reserves is simply through age and practice. The last option is chakra storage Seals."
He tapped the spots Sakura had noticed, pointing out the regions of greatest intricacy spaced along the Seal matrix on his torso.
"This matrix serves to constantly syphon off a small amount of chakra from my circulatory system and push it through an artificial secondary coil network. The chakra is kept stored in the redundant network until a point where my own bodily reserves begin to slip dangerously low, whereupon the flow reverses to feed the sealed chakra back in. It effectively grants me significantly increased reserves, though as the Seal consumes more chakra the larger it grows there is an upperbound; about ten times my normal chakra capacity. Since the rate of chakra generation is proportional to the size of one's reserves, and mine are comparatively small, filling the Seal to the point where I might be on par with, say, the Hokage, would take the better part of a month. I try to avoid doing anything very chakra intensive as a consequence."
Once clothing was back in place, their sensei gave them a rather close inspection, making Sakura feel a bit uncomfortable again as he poked and prodded. He stood back a bit and seemed to be eyeing Team 7's clothing for some reason.
"Seals are generally not the end all and be all for powerful ninja, but very frequently they constitute an extremely potent trump card in your arsenal. Unfortunately, Jiraiya of the Sannin is the only individual generally acknowledged to have mastered the art alive in the world today. There are others who claim mastery, but the best practitioners of the art died along with the rest of Naruto's clan in the fall of Uzushio during the Second World War; even Jiraiya-sama pales next to them. I am competent, possibly even an expert, but that is not the same things as true mastery I fear. Hmm. We'd want to shave some of your hair off."
"What?!"
Sakura blinked and clutched at her cherry blossom strands. Her male teammates seemed perturbed as well, though not quite as vocally.
Dark eyes blinked under the shade of Sensei's hood.
"For the Seals. Chakra Storage for you. Maybe the Mystic Palm for Sasuke, and the Sensory Amplifier for Naruto."
Sakura's hands loosened their death grip a bit.
"You're going to give us Seals like yours?"
Sensei nodded, head slightly cocked.
"Eventually, if you like. Only a single one, the rest you'll want to design yourselves after some more instruction. Seals are my last area of true expertise rather than mere competence, so I would be quite put out if you weren't all at least able to whip up something simple by the time you get promoted to Chunin. Sakura; you're female. That means your reserves will always be smaller than Sasuke's and Naruto's. It doesn't matter how much you train or how hard you practice, your reserves will always be about 10-15% smaller than an identical male. That deficiency comes paired with better chakra control, but that's irrelevant at higher levels since even someone with reserves as large as Naruto's can eventually train to get nearly perfect control. You can't force your reserves bigger. Seals will supplement you though, and allow you to pull even with your teammates."
Turning to Sasuke, the older Uchiha gave a slight nod.
"The Uchiha tend to have slightly larger reserves in general which we burn through a touch faster with the Sharingan, but that should be less of a problem for Sasuke, even if he chooses to specialize in flashy, useless Ninjutsu like most of the clan did. Much more likely to cause trouble is the mental instability that comes with overuse of the Sharingan."
Sasuke scowled, and Sakura felt simultaneously offended and worried. She had looked into her beloved's family a little (she was going to marry a clan heir after all) and she hadn't found anything like that. Although, there was that one report about early onset dementia…
"Remembering every single face you kill tends to lead to sociopathy, and the pseudo-precognition often generates megalomania. Those side effects can be handled, mostly, though you'll need extra therapy as you get older. I recommend alcohol. And pretty girls. Pretty girls with handcuffs...and maybe a flexible chap or two..."
The Genin pulled back a little, looking at the Jounin askance as he covered his moment of embarrassment with a cough.
. . .
A/N: More exposition, but we'll be through it soon.
Hiroki actually lost an eye to that Kumo-nin, but fortunately he had recently acquired a particularly nice spare, so he didn't mind too much.