*(At 4 PM)*
After following the Chief for the whole day, Kaida asked, "Chief, I carefully watched you perform your tasks. Can I get some practical experience now?"
"Kids these days are so impatient," the Chief replied. "Normally, you'd train for at least a month before getting near any patients. But since you're Mitsuru-sama's student, I'll cut that time down to a week."
The Chief then added, "My shift is over, so you can head back or go read some books," before leaving.
'Since my brother promised to teach me Genjutsu after this, I'll let my shadow clones handle the reading,' Kaida thought, using the Wind Instantaneous Movement Jutsu to quickly head home.
...
Shisui, having rested, was training in the garden. Despite being an elite jonin at only 12, he was still far from his prime. This made him a prodigy both within the Uchiha clan and in Konoha.
Kaida entered the house, saw Shisui, and walked toward him. With his Sharingan active, Shisui noticed Kaida as soon as he entered.
"How was your day?" Shisui asked.
"Boring. I have to shadow the Chief for a whole week without doing anything," Kaida replied.
"Observation is important for learning, Kaida. Take it seriously," Shisui advised.
"Okay, brother. Now can we start our Genjutsu training?"
"Sure, let's head to the training area," Shisui said, using the Body Flicker Jutsu to disappear.
'Even with my Sharingan, I can't follow his movement. He's so fast,' Kaida thought as he activated his own Sharingan and used the Wind Instantaneous Movement Jutsu to follow.
When Kaida arrived, Shisui was casually standing near a tree. Kaida disrupted his chakra flow to check if he was under any illusion. Shisui vanished and reappeared behind him.
"Good, at least you remember the basics. Now, try to divide your chakra between Yin and Yang as much as possible," Shisui instructed.
Activating his Sharingan, Kaida began dividing his chakra, and after five minutes, he projected a ratio of 91:9, with 91% Yin chakra.
"That's good enough. Now stop," Shisui said. "We're moving to the next phase, which is both easy and tricky."
Kaida nodded and deactivated his Sharingan.
"You just need to target the eyes of your opponent and send your chakra to their brain, specifically to the cerebral nervous system where the spine connects to the brain. Once you've established a chakra pathway, think of what you want them to see. The closer it is to reality, the easier it will be to fool them," Shisui explained.
"What do you mean by 'closer to reality'?" Kaida asked.
"It's simple. Like earlier, I made it seem like I was standing here. Since you expected me to be here, your brain didn't need to be forced to accept something unusual. With enough control and chakra, you can even do something like this."
Shisui snapped his fingers, and the day turned to night. Crows surrounded them, and Shisui grew black wings from his back. Kaida's immediate thought was, *'So cool.'* He tried to disrupt his chakra but was shocked when the illusion didn't break.
Shisui chuckled at Kaida's expression before stopping the Genjutsu.
"How did you do that, brother? I couldn't break the illusion even after knowing it was Genjutsu," Kaida asked in amazement.
"I made it seem like you dispersed your chakra when, in reality, you didn't," Shisui explained, smiling.
"Will I be able to do that someday?" Kaida asked.
"You will, but only when your Yin chakra is at least 96% pure. For now, let's focus on the basics," Shisui replied.
"Who am I going to practice on?" Kaida asked.
"Use your shadow clones," Shisui said.
"Will Genjutsu even work on shadow clones? They don't have cerebral nervous systems, right?" Kaida questioned.
"Yes, they don't have a true nervous system, but they have something similar. Otherwise, how could they learn and help you train? They need some form of 'brain,'" Shisui explained.
"Oh, I see," Kaida said, thinking, *'If shadow clones could resist Uchiha Genjutsu, they'd be the perfect counter, and the Uchiha's power wouldn't be so feared.'*
"Now, start your training," Shisui urged.
Kaida created a shadow clone and tried projecting his Yin chakra to its eyes, which was easier with his Sharingan active. He connected his chakra to the clone's "brain" and made it see a rabbit nearby.
"Did you see a rabbit?" Kaida asked.
"No, it wasn't a rabbit. It was something terrifying. Let me show you," the clone said before dispersing.
Kaida received the memory and realized he'd accidentally made the clone see a flesh monster instead of a rabbit.
"Were you hoping to get it right on your first try? Keep practicing. Once you master this, I'll teach you a jutsu that will improve your understanding of Genjutsu," Shisui said, using the Body Flicker Jutsu to rest in a tree.
Kaida created another clone and continued practicing. After two hours, Shisui called out, "I'm heading back. Come find me when you've either succeeded or run into trouble."
Kaida nodded and continued practicing. Controlling chakra outside his body was difficult due to the imbalance between Yin and Yang, but he persisted.