Naruto: Chakra System

The main problem for Kakashi regarding his own training was that he had very few areas to focus on, especially at his current age, having already many techniques and abilities. He thought about it and noted a few areas he could train in by himself, apart from normal physical training.

One was, obviously, Medical Ninjutsu, which was available in Konoha and something he could learn. However, thinking about the Five-to-Seven-inch-thick medical books gave him a headache.

He mused, 'I can try learning Mystic Palm Jutsu in the future. Healing techniques would be very useful, but in the future, maybe when I have Sakura learn Medical Ninjutsu.'

A second area was Sage Mode, the Senjutsu art, but that wasn't available to him currently. Only three people in ninja world, he could visit regarding this.

Out of those three, two were simply out of reach—Orochimaru and Tsunade couldn't be easily found or approached. That left only Jiraiya, who was currently not in Konoha.

Kakashi considered, "Jiraiya will come during the Chūnin Exams, which is about half a year from now. I can ask him about learning Senjutsu then. Besides, one of the requirements for learning Sage Mode is high chakra reserves, which I have now."

The third area was Fūinjutsu, or Sealing Ninja Arts. In this, Kakashi had a basic understanding and knew various seals.

One notable technique was the "Evil Sealing Method," which was also a high-level sealing technique. However, he wasn't a specialist and didn't possess very high skills in Fūinjutsu.

Even his Evil Sealing Method was useful only against lower-level curse seals and couldn't fully stop the effects of Orochimaru's curse seals and many others, just as shown in the anime.

Kakashi thought about it and stated, "I have a good foundation in Fūinjutsu, and in Konoha, the Four-Symbol Seal and Eight-Trigram Seal are available for me to learn. I can try practicing them. Moreover, if I get the chance in the future, I can also try learning the Flying Thunder God Technique, which also requires quite a high mastery in Fūinjutsu."

Kakashi remembered from his memories that the Four-Symbol Seal and Eight-Trigram Seal had been part of Konoha since the time of Hashirama Senju. Mito Uzumaki, being skilled in Fūinjutsu, had contributed them to Konoha; even Tobirama might have learned Fūinjutsu from her.

However, these techniques weren't easily accessible, as the Eight-Trigram Seal was considered an S-rank Sealing Technique and was deemed a forbidden Jutsu, similar to the S-rank Sealing Technique, Dead Demon Consuming Seal, and was secured in the Scroll of Seals. However, the Four-Symbol Seal wasn't considered forbidden, but it was also a high-level Fūinjutsu technique.

Even this alone wasn't accessible to just anyone, especially not without the Hokage's permission. However, Kakashi was in luck in this case, as he had a close relationship with Hiruzen as a loyal Konoha Shinobi.

If he asked, Hiruzen wouldn't directly refuse him. Though he might not easily give permission for the Eight-Trigram Seal in the Scroll of Seals, the Four-Symbol Seal was still within reach, and Kakashi could acquire it and learn it.

Then Kakashi pondered, thinking if there was anything else he could train in. After a few minutes of thought, he recalled something.

"Yeah," he said, "I can try merging Rasengan with Nature Transformations."

Kakashi had already copied and learnt the Rasengan years ago, but due to its high chakra requirement to be used at full strength, and Kakashi himself possessing his own S-rank technique, Raikiri, he didn't use Rasengan much. However, this Kakashi knew that Rasengan far surpassed Raikiri if it was merged with Nature Transformations.

Naruto's Wind Style Rasengan, which he named Rasenshuriken, was a very deadly attack that even helped in killing Kakuzu, destroying two of his hearts instantly. Rasenshuriken attacked the target at a cellular level, severing chakra pathways and causing immense internal damage.

However, this also negatively affected the user, as Naruto also suffered self-inflicted harm in the anime when he used it. Kakashi thought, "But this problem can be solved with Sage Mode transformation, as that provides stability and power to throw the Rasenshuriken."

One of the main problems with Rasenshuriken was that it couldn't be thrown and had to be used at short range, otherwise it would vanish. Sage Mode could solve this problem.

However, for Kakashi, another matter was trying to create either Rasenshuriken or merging Rasengan with some other Nature Transformations, which obviously needed a lot of time, even more than what Naruto needed in anime. Even with his increased chakra, he still couldn't use hundreds and thousands of Shadow Clones like Naruto.

Moreover, using too many Multi-Shadow Clones could also be dangerous, as it could lead to memory overload and mental exhaustion. Only Naruto wasn't affected by it, because of his Uzumaki lineage, enhanced mental fortitude from Kurama, and Uzumaki traits, but Kakashi would be if he used them in high numbers.

With his current chakra, he could create up to 50 Shadow Clones without any problem. Though he could create more, that would become very taxing on his chakra reserves.

And considering his mental fortitude, Kakashi thought he could use up to 15 to 20 Shadow Clones at the same time without suffering any mental damage from their dispersion. But he was confused, from where should be start first.