The new set of books Hiruzen had allowed me to have was, just like I had anticipated it to be, almost entirely comprised of the studying materials afforded to all Shinobi hopefuls at the academy. Which was to say, a slightly more chakra centric base of knowledge which I had known wasn't taught to the civilians until they reached the age of eight and exhibited enough potential to be allowed into the Ninja curriculum with all the clan children.
Even then, the material was nothing to really write about, as just like I had gathered from my little time alive, Shinobi jealously guarded any and all information about their arts, even the most basic ones. My time reading some of Iruka's old materials had already showed me that pupils were prohibited from creating written copies of their instructions, even for the three academy techniques.
It was an eye opener for me on how even Sasuke, whom should have had the whole Uchiha compound at his disposition, had never learned any Jutsu beyond the Fireball his father had taught him as a child.
It was the rarity of such material that had made Naruto's attempt at stealing the Scroll of Seals such an egregious crime when one realized it was the sole Ninjutsu manual formally authorized by the authorities.
Of course, I would bet an arm and leg that tons of Clan Shinobi were breaking the rules and illegally storing knowledge in their compounds, something I was sure the Hokage knew of and tolerated somewhat.
My academy books, I could see, despite my not yet taking the time to fully read beyond a quick cursory leafing through to scan them in memory, were extremely minimalistic in their contents. The tomes barely went into detailed theory, favoring short explanation of concepts and were much less thorough than I would have expected them to be, probably so one had to actually be present for academy lectures to learn anything worthwhile.
The little amount of information I could glean from my cursory scanning of the books was still enough to let me know the Shinobi curriculum was more a question of memorization and understanding a large amount of information, rather than a complex field like I had theorized it to be.
In other words, the Shinobi curriculum would be, for the most part, extremely easy to breeze through for someone with a great memory, like Sakura and a total joke for my cheating sponge-like brain.
Technically, I no longer needed my books after I was done scanning them, but I still knew I would be putting them away on my shelves if only for appearances' sake.
A bookshelf was always prettiest when it was full.
Still, now that I had stored their contents in my brain, it was time for me to set my mind to actually learning about the subject I had been so excited for since I had discovered what Universe I had been reborn into.
Chakra, like the fictional show had shown me, was described by my books as the mix between physical and spiritual energy present in every facet of this world and manifested in absolutely all living creatures, though only a select few had developed the ability to mold it in a specific manner to help them accomplish impossible feats and overcome the limits of their bodies.
Generated somewhere in the gut, human chakra was first pumped into the heart, brain and all other organs of the body through a series of 361 connected pressure points commonly referred to as Tenketsus.
Thirty-eight of those pressure points were apparently situated in the hands, four in the palm and three per finger, which was how hand seals had come to be, the different positions of the hands causing chemical reactions through the chakra system of a person.
It was a little surprising to learn that Jutsus, rather than pseudo-magic were actually a science built on chemistry and the reactions were a direct result of the movement in the chakra stream, though if one had enough control over their body and a high familiarity with the technique, the effects could be replicated through sheer power of will.
From my reading, I learned that while any shape of chakra could cause a reaction into the real world, the most useful ones were the set of twelve hand seals which had over the years emerged as the most versatile and easily recreated way to shape the chakra stream to build upon and create techniques.
I recognized most of them from the fictional universe, as the animals of the Chinese Zodiac; rat, ox, tiger, hare, dragon, snake, horse, ram, monkey, bird, dog and boar signs with each one having its own meaning and use.
Dog for example was surprisingly useful for anyone attempting to manipulate chakra into the Natural element of water, while Bird had a similar effect for Wind Style manipulations. Tiger was good for Fire techniques, while Horse helped when molding Lightning chakra. The majority, however, were much more versatile and exhibited lots of versatility, such as how the Ram sign served as an amplifier and was often added at the end or at the beginning of any given sequence in order to greatly increase the rate at which chakra was being built up.
I was honestly quite pleased to see a logical framework in place for the power system of this world, rather than some magical mumbo jumbo fantasy worlds had accustomed me to in my prior life, though honestly, I should have seen it coming.
Orochimaru was the most fanatic Ninjutsu enthusiast I knew of and he was arguably the most influential scientist of his era.
At least, now that I had read the contents of the book, all this information would now be forever stored in my brain for use at a later time.
I had been somewhat disappointed at the book's presentation on the practical side of things, seeing as most of it was spent detailing the path chakra took from its creation to the rest of the human body before being released. Only the leaf concentration exercise had been mentioned in the book as a way to train one's chakra without any specific guide or tips, quite disappointing, really.
From what I could see, the exercise was exactly the same as the one shown in the fictional series, requiring the person to hold a leaf on top of their forehead and concentrate on it as the focal point of their thoughts, with the sole purpose of feeling the leaf, being aware of it, to the point where it could stick upon the user's brow due to sheer concentration. Over time, the feat of moving it all over the body, without a single touch, and through chakra manipulation alone could become feasible.
Like so many things in life, innate ability was a very important part of chakra control, some people were blessed with almost perfect control naturally like Tsunade and Sakura, but it was one of the skills where hard work could breach the gap in time and I couldn't help myself from feeling somewhat relieved that my ability in this field would be tied into my hard work rather than luck, and this regardless of my Jinchuriki handicap. I could have top tier chakra control if I worked hard on it, even if Kurama decided at some point to be a jerk and shut down my control, like he had done for the real Naruto.
Standing up from the chair I had occupied and stretching to brush off the stiffness of my body, I sent a quick peek at the wall-mounted clock to confirm I had just spent four hours to read my first book.
Not terrible, but definitely faster than it would have taken to actually peruse the physical pages.
Urged by the grumbling of my now starving stomach, I was happy to discover Hiruzen had taken it upon himself to have my pantry fully stocked, leaving me with enough to last a week or too before needing to do some shopping.
Having read about the economy of Konoha, I was grateful for the kindness, as it would help in my penny pinching.
Unlike the fictional Elemental Nations, this world's currency, despite being called Ryo, did not actually function as a replacement for the Yen where increments of one hundred were the norm, but was modeled much closer to the Western style of currency in my previous world where one Ryo was the lowest possible denomination.
Three Ryo was generally enough for a quick meal at a decent food stall, while 500 Ryo was the standard rent for the general purpose one person bedroom flat commonly issued to Konoha's orphans.
A thousand Ryo stipend, like mine, while not being a great amount of money on its own, would prove more than enough to ensure I would always have food on my table, clothes on my back and some disposable income as well as a good chunk of savings, provided I was not grossly overcharged, of course.
I still had some trouble believing I was allowed to live on my own at such a young age, especially considering that for all intents and purposes and as far as everyone was concerned I was still a four years old child, rather than the mature for his age teenager I had truly been prior to my death.
My living arrangements would have probably seen the Hokage arrested for criminal negligence had we still been in the twenty first century, but seeing as children barely a year older than me had been allowed on the front lines of a World War in this universe, I was better off getting used to such irregularities.
Trying to apply age to a world like Naruto always felt like a losing proposition, anyways.
I had never gone to school, and even then I knew no twelve years old middle schooler could have handled being thrust Hunger Games style into a death tournament for the entertainment of old rich assholes and the chance to become a Chunin.
One quick meal of steamed vegetables and rice saw me be ready for some more introspection over my existence.
Ever since I had met Kurama and been informed of my rebirth, I had had my suspicions about my constellation and it's impact on my life, but now that I knew for a fact the human body contained exactly the same amount of chakra points as I had nodes in my subconscious, I was certain each little ball of energy I had nurtured had been one of my tenketsu.
The discovery itself was reassuring as it now gave purpose to my daily meditation on the nodes, but it also meant I had to reevaluate how I interacted with the system I visualized anytime I closed my eyes.
At first, I had half-expected the structure to be an acyclic graph of nodes with multiple pathways between each orb. As my tubes grew and did so of their own accord, without any input of mine beyond choosing their shape and internal structure, I had disregarded the idea and accepted the system as being one very long line with hundreds of stops in the way.
Now, however, I knew that wasn't the case anymore. My chakra system was a tree of nodes, starting from my core, and going down to my extremities, with each singular node having one and only one possible path to feed off the energy of my core, allowing me to determine two things for certain on how I felt about the concept of chakra.
First and foremost, the Gentle Fist was the scariest and most terrifying fighting style in this world, as only one single path existed to feed the tenketsu, meaning if a Hyuuga managed to touch you on the shoulder, the rest of the arm would be completely useless as the body had no redundancy in place in case of failure.
Secondly and most interestingly for someone of my particular abilities, it meant that every single of my tenketsu had an optimal route to follow from the core to its location in order to become operational.
The fact chakra behaved in such a way was a true blessing for me, as it informed me my nodes would behave in a binary manner at any point in time.
Either they were actively molding chakra or they were not.
In other words, it was possible for me to use my perfect memory to memorize the feeling of sending a stream of chakra from each and every single point of my system to any other, in order to optimize both the speed of the action as well as my ease to do so.
I would still have to work hard on actually learning to use the energy source itself, of course, as well as improve on the precision of my control outside of my body, but I was confident in the possibilities I had at my disposal now.
Unfortunately, two possibilities to the power of 361 pressure points meant I would have to spend seven thousands lifetimes if it took a second to memorize every single possibility, which was honestly a bummer and put a limit to my ability to cheat the system.
It was while smiling with newfound optimism that I made my way outside, towards my backyard and the few trees I had on my land, having decided to try my hand at properly channeling chakra for the first time.
I had wanted to work on my chakra control since the moment of my birth, and I was certain anyone could have read my excitement for it simply by the speed at which I had picked fallen leaves from the ground.
No matter how you looked at it, I was probably much smarter than the average child would ever be, thanks to my overpowered recall ability, and the possibility it provided of visualizing all my pressure points in my mind.
Therefore, I expected my innate gifts to greatly boost my control over my body, even without access to the Byakugan or the Sharingan to correct my mistakes in real time.
Those were bullshit abilities anyway, and even as blessed as I was, it was annoying to compare myself to the possessors of the Rinnegan and their stupid perfect control for all natures.
I knew I could overcome every disadvantage with enough training, but sometimes I felt like Kurama's distaste for eye implants would hold me back greatly. Things would be much easier in the long term if he allowed me to steal some of Sasuke's chakra and awaken my own Six Paths abilities, but I had absolutely no chance of survival without Kurama's help, so I was better off never interacting with an Uchiha in any capacity and avoid risking the Tailed Beast's ire.
It wasn't really a big deal however, as I had the will power to train as hard as humanly possible every day for the next decade of my life. It also helped that I was starting at a younger age than almost anyone in this current era, bar perhaps Kakashi. There was no reason why I should not be able to get myself to a respectable level in that time frame, even compared to those with gifts from birth and despite my reluctance at becoming a tool of war with only a single purpose in life.
I knew that becoming strong was the only way to ensure my survival in this crazy world, and so I returned to the task at hand, unlocking my chakra.
I had known for some time now that the very first step in unlocking one's ability with the spiritual energy was meditation, as in its base form, chakra was simply our life essence, and becoming aware of it was an act of self-discovery and reflection on one's own conception of the self.
Having spent months and months in both lives meditating, I had played with my constellation often enough to notice the strange sensations residing just outside of my perception when I fed my nodes.
I had on many occasions been on the cusp of grasping it, if not for my actual desire to not attract much attention on myself by developing it too soon in the orphanage and under the watchful eyes of both Hiruzen and Danzo's agents.
Thankfully, I had now reached a more appropriate age where even if I excelled, there was already precedent and I would be, at best, seen as a regular genius, rather than raise alarms about my tenant taking control over meek little me or some other nonsense.
Closing my eyes, I sat down with my legs crossed on the grass and slowed my breathing, pushing my awareness as much as I could towards that feeling of warmth I had noticed before, letting it settle into me. I actively stoked it, willing the embers to grow brighter as my books recommended, until it went beyond my control and I felt it stir and burn throughout my body, flowing into my veins and lighting up every single one of my pressure points at once, quickly propagating through my stars, from the gut towards the heart, constricting my lungs in the process, before jumping into my brain and from there tickling all my extremities, making me clench my fists and wiggle my toes.
I felt like I had just gained a new sixth sense, an euphoric feeling allowing me to take stock of every single part of my body, each organ, my arteries as well as every pathway between my nodes, making me more aware than ever that I was a complex system of threads and energy, in a manner I had never been able to appreciate when previously working on my tubes and nurturing my orbs.
Most people, I knew, would have taken weeks to accomplish this step, doubly so for children whom might not yet be fully in touch with their nature or comprehending fully their existence on this mortal plane, but it was barely worth a mention for the metaphysical being that I was, seeing as my presence in this world at all made me some freak of nature.
Having what I hoped to be massive chakra reserves also helped, though there was no way to tell how big they were compared to others, my only reference point being Kurama's sun, which was orders of magnitudes larger than I was.
Happy with the progress, but knowing the real work of chakra control would only begin when actively trying to do something with it, rather than simply confirming I had reserves as I had done. My having reserves should have been self-evident for my Jinchurki self, anyways.
Picking one of the leaves, I threw my head backwards and sticked the leaf on my forehead before closing my eyes and communing with the feeling I had just discovered in my gut, urging the chakra to travel up my navel and towards my brain.
Unfortunately, nothing happened and the leaf fell down to the ground the second I righted my head's position, my efforts not affecting the outside world in any way whatsoever, though I could follow the energy flow towards the correct extremity when I had closed my eyes.
I repeated my actions numerous times, hoping to keep the leaf stuck to my body despite gravity's best efforts to make me drop it, but no matter how hard I tried, I came up empty, showing me once again the danger of underestimating the amount of work required to accomplish anything in this world. There was a vast difference between understanding how to do something and actually being able of doing it, a notion which I was forgetting far too much lately, it seemed.
I sighed in disappointment, before gasping when I realized, upon opening my eyes, that I was actually panting, the mental toll of concentrating my chakra, even without result, being much higher than I had expected it to be.
I could see now why the basics of chakra control were not a skill generally taught to children prior to the age of eight, as well as why it was a reoccurring part of the curriculum for four years.
Even had I been born without the cheating advantages of knowing exactly where all my pressure points should be and even after discarding how easy it was for me to detect my chakra thanks to my overabundance of it, I was confident anyone remotely competent could learn the basics of the exercise in less than a day. Despite it being such an easy concept, however, the academy would need to spend enormous amounts of time teaching their pupils due to how utterly exhausting it was to attempt.
I had barely been able to hold it for a few seconds and I was already having trouble breathing.
Non-Uzumaki that did not have access to Kurama's help would probably collapse to the ground in exhaustion on the first blink of their eyes after attempting it.
This realization shed a bit more light for me on how utterly ridiculous the children that had graduated early were. Especially those like Shisui and Kakashi whom had done so at four and five, as unless they had been born with flawless chakra control from birth, they must have started working on it from the moment they had gained awareness.
Child soldiers were really something else in this world.
Still, as things stood, I would still come out on top, I knew as despite my initial failure, I was already feeling better and ready for another round in barely five minutes, unlike the other children whom would probably require a few hours, if not a complete day between attempts.
Assuming the worst case scenario where a child could only do the exercise once per day and required the full four years to master it, I would only need about ten days to achieve the same results, assuming I maintained my current rate of one attempt per five minutes for sixteen hours a day.
I doubted I could really be that efficient, but at most, it would make me two weeks to achieve the 1460 attempts required.
It could never be overstated how much I loved my healing factor, especially considering how much more efficient than a normal child I was at my base level, without even having the Shadow Clone Technique at my disposal.
At this rate, I was going to be a monster much sooner than expected...