Uchiha Sora turned to face the students below. "Can anyone tell me first—what is the essence of genjutsu?"
The classroom fell silent for several seconds.
Orochimaru raised his hand.
Uchiha Sora nodded. "This student, please answer."
Orochimaru stood up, his tone calm.
"Genjutsu is a ninjutsu that creates false perceptions by using chakra to interfere with an opponent's brain nerves or the flow of chakra within their body.
Its essence is deceiving the five senses, making the opponent see, hear, and feel things that do not exist."
"Very accurate."
Uchiha Sora gestured for him to sit down. "It seems some students did their reading in advance.
That's right. The core of genjutsu is deception.
But the prerequisite for deception is that your chakra must be able to invade your opponent's chakra system."
He picked up a piece of chalk and drew a simple diagram of chakra flow on the blackboard.
"When casting genjutsu, the caster's chakra invades the opponent's body at a special frequency, disrupting their chakra flow.
If the target cannot sense this intrusion, they will fall under the genjutsu."
He paused and looked at the students. "So here's the question—how do you sense whether you've fallen under genjutsu?"
More people raised their hands this time.
Uchiha Sora called on a girl—Kuno Chigusa from Gen's team.
Chigusa stood up and said somewhat nervously,
"If the environment around you suddenly becomes unnatural, or if the people beside you behave strangely, you may have fallen under genjutsu."
"Not bad. That's the wisdom of experience."
Uchiha Sora nodded.
"But if it's a sophisticated genjutsu, changes in the environment will seem completely natural, and you won't notice anything unusual.
At that point, you need another method—checking your own chakra."
He raised a hand and formed a seal.
"When you suspect you've fallen under