Midsummer is coming to an end, and there is a hint of coolness in the evening.

With such a high vegetation coverage rate in the Fire Country, the weather in this season is still quite pleasant.

For Uzumaki Naruto, life was not so wonderful.

"Why is it so difficult to change the nature of chakra?"

The feeling of having energy but not knowing where to use it is really uncomfortable. Even after asking Asuma Sarutobi, who is proficient in wind escape, for advice and finding a clue, I am still far from mastering it.

Changing the properties of chakra is a practice that cannot be cheated and is quite boring.

Kakashi Hatake naturally asked Naruto Uzumaki to use Shadow Clone to speed up his training.

At the same time, Kakashi also asked Mizuki for help, wanting to use the concentration technique that Mizuki used to help Sakura practice or other methods to alleviate the mental shock caused by Naruto's practice, but was rejected by Mizuki.

"You are too concerned, Kakashi. Have you forgotten that the Multiple Shadow Clone Technique is a completely forbidden technique? It is already very dangerous for you to use it to accelerate the change of chakra properties. If you add to Naruto's burden, the risk will increase exponentially."

"Is it that serious?"

Looking at Kakashi who was somewhat puzzled, Shuimu, who was sitting behind the desk, explained helplessly:

"It's true that the experience and memory will be fed back when the shadow clone disappears, but the fatigue caused by the mental shock will also accumulate. When it becomes serious to a certain extent, the ninja will lose the ability to move or faint. This is the human instinct for self-protection. Coma is a physiological phenomenon that regulates one's own functions. If you just try to escape, it will have bad consequences!"

"This kind of consequence can be mild or severe. If the impact is minor, then of course there is no problem, but Naruto is obviously not one of them!"

"Sakura's physical fitness is far inferior to Naruto's, but they have one thing in common, that is, the number of shadow clones is not limited by chakra, which is a good thing for practice. The concentration technique I taught Sakura was to make up for her mental and physical deficiencies and let her give full play to the advantages of her large amount of chakra. But I still strictly limit the number of her shadow clones. The reason is that you must know that Sakura's physical strength is far inferior to Naruto's."

"Naruto's physical strength is excellent. If he uses all his strength, he can create hundreds of shadow clones. The consequences are also very serious. If he is not protected, it is likely to cause permanent mental damage. This is a short-sighted move that will not be worth the cost!"

Seeing that Kakashi still didn't quite understand, Mizuki continued.

"To give an inappropriate example, Sakura can run ten kilometers, and Naruto can run a hundred kilometers. The spiritual secret technique can increase Sakura's running distance tenfold to a hundred kilometers. For Naruto, tenfold is a thousand kilometers, which is also beyond his limit. How big do you think the difference is between the damage caused by running an extra ninety kilometers and the damage caused by running an extra nine hundred kilometers?"

"Oh, now I understand!"

Hatake Kakashi suddenly realized.

"With different physical qualities, if it were Naruto, he would definitely do his best to practice. The more shadow clones he has, the greater the instantaneous damage he causes. If this large amount of damage is accumulated in a short period of time, it will have serious consequences."

"That's about it. If you want to use the Concentration Technique, you have to let Naruto control the number of his shadow clones to prolong the time period of causing damage. Instead of doing that, it's better to let Naruto do it. When he is naturally exhausted, he will stop and recover on his own. This may be faster. Naruto's physical fitness and strong will are equivalent to a buffer for physical and mental fatigue. You don't need to interfere. If you change it at will, it will be counterproductive!"

And there is another point. With the amount of chakra Naruto has, the concentration technique is definitely not enough, and he must use a complete soul gathering formation.

When Naruto was training, the shadow clone disappeared instantly, causing mental fluctuations. Then he used sealing techniques to interfere. Who knows if it would affect the chakra of Minato Namikaze and Kushina Uzumaki in his body?

Mizuki has been holding back from attacking the Nine-Tails in Uzumaki Naruto's body until now, just because he doesn't want to affect the chakra marks in Naruto's body.

"Is that all we can do?"

Kakashi nodded, seeming somewhat dissatisfied with Naruto's progress.

"An S-rank ninjutsu that combines form change and nature change. Some ninjas cannot learn it in their entire lives, and you are still being picky!"

Shuimu curled his lips.

"Besides, holding the powerful wind-attribute chakra in your hand is a very dangerous thing. If used improperly, you may become disabled."

"Well, I expected that there would be some risks in practicing ninjutsu!"

Mizuki didn't know what to say. This ninjutsu was originally created by Naruto, and Mizuki was just returning it to its original owner. It shouldn't be difficult to learn. The key was to limit the number of times Naruto could use the Wind Style - Rasenshuriken before he learned the Sage Mode.

Without the protection of Sage Mode, this technique would cause too much damage to oneself.

And its shortcomings are also obvious. Only with the bonus of Sage Mode, the control ability and perception are greatly improved, and it can be used as a throwing-type long-range attack ninjutsu. Under normal circumstances, Wind Style - Rasenshuriken will explode as soon as it leaves the grasp.

With Naruto's reaction ability and physical skills level, the chance of hitting the enemy with this S-level wind-style ninjutsu is too small. The fact that he missed repeatedly when dealing with Kakuzu is proof of this.

Moreover, in the Sage Mode, long-range throwing attacks can greatly reduce the damage of this extremely destructive ninjutsu to oneself.

"Unfortunately, this will mean we won't be able to complete this mission. If Team 7 also participates in the operation to capture the Three-Tails, Naruto won't be able to use this advanced ninjutsu."

"This is enough for now. Just prepare some more Bingliang Pills. Maybe they will come in handy."

Mizuki didn't know whether Sakura and Hinata were making military pills for Naruto. Logically, Mizuki didn't know how to do it, and they probably didn't know how to do it.

As for the others, no one would have the patience to do such a thing. It was natural for Naruto's speed to slow down as he practiced Wind Style - Rasenshuriken.

The improvement of Naruto's overall strength is obvious. The Multiple Shadow Clone Technique combined with the Big Ball Rasengan is enough to deal with many challenges. If he is really defeated, transforming into a tailed beast is enough. How many people in the ninja world can defeat the Nine-Tails Jinchuriki with four tails?

As for the money to buy the soldiers' ration pills, Kakashi would most likely have to pay for it. Having been single for many years, he should not be short of this little money.

However, Naruto hasn't done any missions in the past three years, so he probably doesn't have much savings, and it will probably take him many years to pay it back.