After a month of his usual routine, Yuta completed his library reading on chakra theory as well as its two components – physical and spiritual energy. With that Yuta mostly confirmed his own assumptions on how to make his spiritual energy stronger.

It's as he thought, spiritual energy originates from soul and constantly generated by it, and to improve it there is a multiple ways to do so.

The ways to grow spiritual energy, according to library scrolls on chakra theory, from most efficient to the less ones is:

First – getting experience in combat, especially effective are life-and-death battles;

Second – according to scrolls, sometimes shinobi gets some sort of enlightenment during the life, and that sort of things can improve their spiritual energy greatly, but there is no way to control or predict that sort of things so it's mostly up to the fate and luck;

Third - to practice and mastering multiple ninjutsu and accumulating experience from doing so over time;

Forth – is meditation, there is multiple meditation manuals in the library, it helps to clear the mind, and even slightly increase the chakra quality and quantity, but it's not very effective and because of that it's not very popular practice;

Fifth – is to study, as studying and accumulating overall knowledge is also positively influences the spiritual energy, but it's the less effective way over all of them.

About physical energy Yuta already knows enough, it's just depends on overall stamina and strength of the physical body. All the cells in the body are generating the physical energy.

The healthier and stronger the physical body is, the stronger the physical energy it generates. Some bloodlines can also greatly improve this aspect, like Senju or Uzumaki bloodlines. Those who have Senju or Uzumaki bloodline is usually have ginormous bonus in the physical energy department, their cells generate much more potent physical energy and with that they usually have monstrous amounts of chakra and overall stamina.

According to scrolls, every living being in the world, animals included, have those two energies up to some amount, and they also have chakra system network in their bodies and with that the chakra as well.

The chakra is closely linked with the life force, and if completely depleted – the living being with completely depleted chakra dies. Life force is the energy that depends on the physical energy, and if it's depleted, the result is also death.

The chakra is constantly and automatically produced in the chakra network of all living beings by fusing together the physical and spiritual energy. But sadly there is no records of anyone who managed to control the physical or spiritual energy separately from chakra.

Yuta was very interested in the possibility to be able to control his spiritual energy as well, he doesn't know yet how he can use it in practice and if it even possible at all, but the idea of it is still is very intriguing to him.

There also some interesting theories about Yang and Yin release and their close connection to physical and spiritual energy. There is said that Yang release or Yang chakra is made entirely from physical energy and Yin release or Yin chakra is made entirely from spiritual energy.

The jutsus that use Yang release is very rare and Yang chakra is rarely formed and used by shinobi and it's always used on the user's body itself, like Akimichi clan techniques that manipulates the size and mass of a user's body. The Yang release is also used in the iryojutsus or medical jutsus but there it is used not as a pure Yang release but a mix of Yang release and Yin release. But it shouldn't be mistaken for the legendary Yin-Yang release that the Sage Of Six Paths used.

It's stated that Yang release impossible to use outside of the user's body, because in it's pure state it's can't have a form.

The Yin release is used more often than Yang release. Yin release or Yin chakra is created entirely of the spiritual energy and used mostly to perform genjutsu. Almost all genjutsu, except for some special cases, used Yin release to perform. There is also some secret techniques of the clans that originates on Yin release, for example the Nara clan shadow manipulations or Yamanaka clan mind transfer techniques.

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After learning this information Yuta is already pretty sure that learning genjutsu to a high level is a way to go for him. With his Time control ability that totally dependent on spiritual energy he must focus on straightening his spiritual energy as much as he possibly can.

And with straightening his spiritual energy, in the future he will become very efficient with genjutsu and Yin release as a whole. With circumstances like that, there is not even a question about it, he absolutely and totally must go for the genjutsu mastery later on.

Yuta decided that if he will have the chance to get some genjutsu training – he must grasp that chance no matter what.

With that acquired knowledge on spiritual energy Yuta decided to add a one hour of mediations practice to his usual day routine, to work on his spiritual energy. According to scrolls it's not that efficient anyway, so Yuta doesn't want to spend too much time on it. With one hour every day it will eventually add up to a high amount of hours anyway.

He also already studying at the library daily and that covers the 'Study' way of improving his spiritual energy.

Yuta doesn't know any ninjutsu, so he can't work on that aspect yet. And combat, especially life-and-death battles are out of question for Yuta right now. As well as the seeking of the enlistment.

So with meditations added to everyday schedule Yuta can say that he works on his spiritual energy in the every possible way right now.

'Hm… If I remember correctly, the clone jutsu, that is the one of the three basic jutsus taught at the academy, is actually the basic genjutsu. Now I really want them to teach us the 3 basic jutsu as soon as possible!'

'I wander how long this brainwashing session will last and when they will start to teach us the practical stuff?'

After learning everything that is there about chakra theory Yuta starts to learn fuinjutsu.

At the first days of it, Yuta struggles a lot to find some appropriate basic books and scrolls about fuinjutsu, as most of them contain a lot of technical terminology that Yuta doesn't understand yet.

With days passing by Yuta starts to getting hang of the basics of fuinjutsu and the more he learns the more interesting it becomes for him. Until one day he finally was able to understand what is the fuinjutsu actually is.

'It's actually very similar to the programming languages of my previous life, and making a seal is similar to writing a working program! I never though I will have to do programming in this new life to!'

'That is just ridiculous! Just thinking about my years of working as a software developer in my previous life so that after my reincarnation in the Naruto world I can do the same damn thing but with fuinjutsu… So far it's the most absurd thing I encountered in this world! Damn my luck! Where is my fantasy world with magic? Why, the damn, I have to do programming with fuinjutsu instead?!'

…

'Well… Jokes aside, this is really great! This discovery actually means that I can get in to the fuinjutsu mastery much faster than I would otherwise.'

'There is still a lot of the stuff I need to learn about fuinjutsu before I actually can do something with it, but nevertheless, my skills from the previous life will definitely come in handy here, hehe.'

'From what I learned so far, the fuinjutsu is very archaic and crude compared to the usual programming practices. And its looks like there are a multiple 'languages' used in it, where different fuinjutsu masters used different 'languages' to develop seals.'

'Most common 'language' that is used in seals is all sorts of kanji with a lot of specially developed kanji that used in fuinjutsu only. And there are thousands of them! And this is only in this 'basics of the fuinjutsu' books and scrolls! And different fuinjutsu masters often invent their own kanji to inscribe seals! All of that is just a pure madness from the perspective of a normal software developer!'

'Just imagine the programming where every programmer uses their own mix of multiple programming languages with adding their own parts in it… The world of madness and endless nightmare for any sane programmer!'

'And the saddest thing about all of this is that the fuinjutsu art is performed in this way not without a reason. If one fuinjutsu master creates some defense barrier, for example, without using their own mix of 'languages' with adding their own stuff in to the mix, but he uses instead the most clear and efficient way to create the barrier – the other fuinjutsu master will be able to crack that barrier pretty easily, as he will see through it in a glance.'

'Well, fuinjutsu art is no joke from what it seems. It's works in a way just like the normal programming, but in this world it's important to make the seals in a complex and intricate way, instead of normal programming where the most important thing is that the program is written in the clear and understandable way, so other programmers will easily understand it in a glance.'

'The other difference from the normal programming is that in fuinjutsu you need to inscribe a seal perfectly, with no errors, in one single go. Where in the normal programming you have as much time as you need, with pauses in between, and you can test run it to find and fix the errors, and once written, you can copy your program or any part of it as much as you want. So fuinjutsu is actually a way harder than programming.'

'Well, in my previous life there was no shinobi training, chakra, spiritual energy, nothing like that. And with all that additional things the mind capabilities and the thought process can be greatly improved, and here is also the jutsu like shadow clones exists, so with all of that the art of fuinjutsu is actually possible in this world.'

'Well, it will take a lot of time and efforts to get used to it and learn all of those things for inscribing seals, that will definitely take multiple years just to master all what is present in this library about fuinjutsu alone.'

'But hey, it's not like I'm in a rush, am I? Didn't I wanted to learn and master all sorts of things that this world can provide? Well, here some fuinjutsu for me I guess, hehe.'