Once precise control at the level of the neural network was involved, the difficulty increased geometrically. This not only entailed a requirement for precise chakra control but also demanded that the user have a sufficient—no, a profound—understanding of the human body.
In other words.
Only those who had reached a certain level in the field of medical ninjutsu possessed the qualifications to cultivate the 'Twelve Palaces'!
"As expected, everything requires knowledge!"
Shinji muttered a complaint.
It was only now that he deeply understood why ninjas like Tsunade and Shinnō, who possessed extremely high attainments in medical ninjutsu, were also powerhouse experts in taijutsu. Because only after truly understanding the structure of the human body could one know how to better unleash its potential.
Thinking of this, Shinji snapped his fingers and deactivated 'Takamagahara'.
After exiting 'Takamagahara', Shinji glanced sideways at the clock hanging on the wall. Less than five minutes had passed, whereas he and Mumei had spent over an hour inside 'Takamagahara'.
After briefly adjusting to the flow of time, Shinji stood up and said to Mumei, "Wait here for a moment. I'm going to the hospital to look up some information!"
Mumei nodded. "Understood!"
After leaving that instruction, Shinji arrived at the Konoha Hospital.
In the hospital's archives, he retrieved all the books regarding the nervous system, as well as case studies involving it, and began to study them.
Undoubtedly.
In the ninja world, where chakra exists, the human nervous system was not as mysterious as Shinji had imagined. On the contrary, quite a few ninjas had already taken notice of it and conducted a great deal of relevant research.
According to numerous research reports, appropriate stimulation of the nervous system could enhance brain activity and send the body into a state of excitement, thereby comprehensively improving muscle reaction time and strength.
To this end, the Medical Corps had even developed several potions specifically designed to stimulate the nerves.
Looking at these research reports, the corners of Shinji's mouth curled up.
These research reports had already marked all the areas of the nervous system most susceptible to stimulation. Shinji only needed to do the opposite and bypass these areas to avoid the 'Twelve Palaces' causing excessive stimulation to the nervous system.
"Konoha is indeed full of treasures everywhere!"
Shinji chuckled lightly as he organized the materials he needed.
He had originally thought that this improvement would take at least several weeks, or even months. He hadn't expected that a single trip to the hospital archives would solve eighty percent of the difficulties for him.
As the number one ninja village in the ninja world, Konoha was not only the strongest in power, but the materials and data accumulated over decades were also incomparably rich. Information that would require countless efforts to obtain on the outside required only a simple motion to access in Konoha.
Returning to the Military Police Force building, Shinji called for Mumei, and the two went together to the training grounds exclusive to the Konoha Military Police Force.
Since it concerned the improvement of the 'Twelve Palaces', conducting it in reality was the safest and most reliable method.
Directly pulling up Mumei's right hand, Shinji squeezed it and traced a line upwards from the side of her palm. "Do you feel a slight itch?"
"Mhm!"
Mumei nodded, her face flushing.
Shinji did not notice the inexplicable blush on Mumei's face, remaining focused on her right hand. "This is the area where the hand's nerves are most dense. When using the 'Twelve Palaces' for stimulation, if you can avoid stimulating this small area, perhaps the problem with the 'Twelve Palaces' can be solved."
Mumei whispered, "Oh."
Shinji continued, "Your control over chakra is superior to mine, so I need you to help me test this. Like this: use the original 'Twelve Palaces' to stimulate your left hand, and use the method I just told you to stimulate your right hand, and see if there is any difference."
With that, Shinji released Mumei's right hand.
Seeing Mumei still dazed, he urged, "You can start now!"
"Oh, oh!"
Mumei hurriedly began the attempt.
Activating the 'Twelve Palaces' was already not easy. To treat the hands differently—using the original version on the left hand and the improved version on the right—required such a high level of skill from the user that it would likely filter out 99.99% of the ninjas in the world.
Fortunately, Mumei was an exception!
After failing only seventeen or eighteen times, she mastered the rhythm. Her left hand operated the original 'Twelve Palaces', while her right hand operated the initially modified 'Twelve Palaces'.
And when Mumei began the attempt, Shinji had already fully activated his 'Six-Tomoe Rinnegan'.
Time passed bit by bit.
For the first few minutes, the activity in the fully stimulated left hand was slightly stronger, but the difference was not significant; the right hand also maintained an extremely high level of activity.
When the time reached fifteen minutes, the activity levels of both hands were basically identical.
After passing the thirty-minute mark, the situation began to change. The activity in Mumei's left hand began to decline continuously, while the activity in her right hand remained unchanged.
When the time reached forty-five minutes, Mumei began to frown slightly.
Shinji asked, "What's wrong?"
Mumei replied, "I feel a little numbness in my left hand!"
Shinji nodded gently. "Alright, you can stop now!"
If this slight numbness occurred throughout the whole body, a person in a state of fatigue would generally find it very difficult to detect.
But with a comparison, this slight numbness became prominent.
Having verified the feasibility of the improved method through actual practice, subsequent steps only required refining the details.
Seeing the smile on Shinji's face, Mumei asked, "Shinji, is the 'Twelve Palaces' flawless after the improvement?"
Shinji shook his head and laughed. "How is that possible!"
Mumei was somewhat puzzled. "Does the 'Twelve Palaces' still have problems?"
"Maybe, maybe not!" Pausing, Shinji shook his head. "There's a high probability that problems still exist; we just haven't discovered them yet!"
Any jutsu has room for refinement and improvement.
Even star-level jutsu like 'Impure World Reincarnation' and 'Rasengan' are constantly being improved by later generations.
Therefore, Shinji dared not claim that the 'Twelve Palaces' he developed was truly flawless.
This was also the reason why he hadn't promoted the 'Twelve Palaces' on a large scale for the time being. The difficulty of cultivation was one aspect, but on the other hand, he was worried that the 'Twelve Palaces' still harbored serious hidden dangers.
Just like this time, if not for Mumei possessing extremely high chakra control abilities, Shinji feared he might never have discovered the hidden dangers within the 'Twelve Palaces'.
Over a long period, he, along with Ryuzetsu and Chino who cultivated the 'Twelve Palaces' with him, might very well see their nervous systems completely collapse one day, leading to sudden bodily paralysis and permanent loss of mobility.
However, this incident also made Shinji realize that perhaps allowing more people to join in the cultivation of the 'Twelve Palaces' was the only way to better discover the potential problems within it.