Shizune, instead of walking out, put her hand in her pocket and took out a roll of thread before giving it to Tsunade, who pulled out a certain amount of thread. She then looked at Kira and began to move her chakra from her fingers to the thread.
In a few seconds, the entire thread was coated in chakra.
"This thread is something that I created, but unless someone has perfect control of their chakra, they won't be able to keep this thread stable. If you force too much chakra, the thread will harden and if you put in less chakra than required, then it'll become elastic." she explained as she gave him her thread so that he could see how it felt.
Kira ran his finger along the thread before he tried to stretch it.
"It feels like a normal thread." he commented and Tsunade nodded in response before telling him to do the same thing she did.
Kira concentrated on the thread and slowly inserted his chakra into the thread. The moment he did, he felt a feedback, like he was pushing against something. The closest thing he could relate it to, was a wall made of plastic wrap.
Three seconds later, he tossed a hardened thread onto the floor and asked for another one. He experimented by using too much chakra, a little less chakra and also the perfect amount of chakra.
As for the results? It was just like tsunade had said, but there was a problem. After his three tries, he could tell that she had hidden some information from him and it was the fact that even if he used the perfect amount of chakra, the thread would become elastic.
"You should have told me that I had to shape my chakra into an extremely thin needle first." he said, giving her an annoyed look before pulling out more thread from the roll and this time, he quickly shot his chakra through the thread and gave it back to Tsunade.
The answer was not in pushing against the plastic wrap wall. It was to take a knife and cut through it so the person could pass through and in this situation, if the plastic wrap was 1 millimeter worth of thread, then the person would be chakra.
To pass through from one end to another, the "person" would have to cut open a path for himself hundreds of thousands of times.
But that wasn't all, the plastic wrap had it's own length and breath. So if a person cut it too much, then the entire path would break and in Kira's situation too, the thread would break.
If he cut too less, then the same old thing would happen. Hardening of the thread or making it elastic.
So instead of a "knife", he had to make a chakra needle so thin and sharp that it would perfectly move from one end of the thread to the other without any resistance.
And with such a small hole, the difference in hardening of the thread was negligible.
Tsunade tugged at the thread and gave Kira a weird look before turning to look at the thread once again and tugged it a few more times..
The result was the same as what she always got and the kid in front of her had done it in just four tries. If this didn't scream talent, then what did?
She tossed the thread aside and looked at Kira, "Fine, you pass the test. I'll teach you my strength of a hundred seals."
Strength of a hundred seals was simple in theory, but extremely hard in practice. The users have to store a certain amount of chakra at any point in their body. Yes, not just the head, but any point.
The reason why Tsunade and Sakura used the seal on their forehead, was because as long as their head is intact, they could regenerate their entire bodies. If someone picked the palm as the sealing point, and their arm got chopped off, then they'd simply loose their strength of a hundred seals.
As for how they'd store chakra at this point? It was simply chakra redirection, but it required extremely precise control as they would have to keep sending chakra to the seal at a steady pace and they would have to do it even while sleeping.
One could increase the input of chakra to the seal when they wake up, but this increase had to be gradual and before sleeping, they'd have to tone it down to a point where their body could do it passively while they slept.
Without extremely precise chakra control, forming this seal would be close to impossible.
After teaching him the theory behind the strength of a hundred seals, she also taught him two more techniques. One was the Creation Rebirth and the other one was basically a combination of creation rebirth and strength of a hundred seals.
Also named as the one hundred healings jutsu. Learning the theory of these jutsu's didn't take too long and once Tsunade made sure that Kira had the ability to direct his chakra to the seal, she let him go back to Konoha while she stayed back, wanting to gamble more.
As Kira headed back to Konoha, his thoughts wandered.
'Almost all the preparations are done. There's only one thing left to do and once that is done, I'll go back to Konoha and I'll probably be sent to the war.' he thought as he walked in the direction towards the land of water.
It took him only a week's worth of time to get to the nearest island that was under the jurisdiction of the land of water. It had a village, but most of the island was a literal forest. As for why he didn't use his flying raijin? It was because he had never visited this place and due to this, he never had the chance to hide his Kunai at this island.