Genjutsu works by affecting the enemy's five senses. Since the vast majority of these techniques require visual contact to take effect, theoretically, if one simply closes their eyes, most Genjutsu will be rendered useless.
"So that's how it works!" Maito Gai exclaimed. He felt as if he had just discovered a broad, golden road to defeating Genjutsu specialists!
"Are you an idiot? How are you supposed to fight with your eyes closed! If you can't see the enemy's movements, isn't that just seeking death?!" Obito mocked. As a perennial dead-last, the opportunities to look down on another dead-last and find a sense of superiority were few and far between.
If Kurenai-san had known a bit more about Hagoromo, she wouldn't have let her emotions get the better of her. She would have known that Hagoromo was exceptionally skilled at provoking his opponents.
"Then stick to your strategy and don't regret it when you lose!" Kurenai said with a hint of resentment. Without waiting for Hagoromo to signal his readiness, she flicked her wrist, sending two shuriken whistling toward him.
She was a Genjutsu ninja, true, but that didn't mean her arsenal was limited to illusions. She knew how to use shuriken and kunai just as well as anyone else!
Hagoromo's eyebrows twitched slightly, and he promptly opened his eyes. This classmate of his played for keeps—the two shuriken were aimed straight for his chest!
However, shuriken were a form of attack that rarely worked against any ninja in a head-on confrontation. Hagoromo swiftly pulled a kunai from his tool pouch and performed a precise parry in front of his chest.
With two crisp clangs, Kurenai's shuriken were struck down without a miss.
"I thought you were going to fight with your eyes closed?" Kurenai mocked, seeing that he had opened them.
Teachers generally didn't stop verbal sparring during a match, as it was often considered part of psychological warfare. And Hagoromo was indeed capable of disrupting an opponent's psyche, but he wasn't speaking for tactical reasons. His reason was much simpler: he just genuinely enjoyed talking trash.
"Eh? Didn't I say it? Closing my eyes is for dealing with your Genjutsu. Did you use Genjutsu just now? Oh... so that's what Yuhi-style Genjutsu looks like. We usually call that kind of thing a 'shuriken' where I'm from." Hagoromo adopted a face of innocent ignorance, asking in a tone of sincere inquiry.
Hagoromo's wicked personality... The same thought flashed simultaneously through the minds of the three people who knew him best.
Predictably, Kurenai—feeling toyed with—grew even more enraged! In an instant, three more shuriken were flying toward Hagoromo.
Hagoromo parried them away again and said, "Forget the shuriken. Aren't you going to use Genjutsu? If you don't, you're going to lose. I'm much better at shurikenjutsu than you are."
Just then, Kurenai noticed a shuriken circling in a wide arc, bearing down on her!
When did he—?!
She hadn't seen Hagoromo make an attacking motion at all. How had he thrown a shuriken with absolutely no warning?
However, because the shuriken had to circle into her blind spot before suddenly appearing, the wide arc sapped its momentum. By the time it reached her, it lacked power. She swiftly raised her kunai to parry it.
Clang!
Hagoromo's attack seemed to have failed.
Kurenai was just about to mock his shurikenjutsu—thinking such a petty trick could never hit her—when she suddenly heard someone shout in desperation: "Watch out! It's a Shadow Shuriken!!!"
"What?!"
Hagoromo hadn't thrown one shuriken, but two. Both were traveling in a wide arc toward Kurenai, one stacked above the other. The bottom shuriken was hidden perfectly in the shadow of the top one, skimming just ten centimeters above the ground. Furthermore, when it was only a meter away from Kurenai, it suddenly veered upward with sharp lethality, heading straight for her chest!
Having been warned, Kurenai realized her peril instantly. She performed a frantic, clumsy dodge!
The shuriken tore through her sleeve, leaving a shallow graze on the outer side of her arm. If it hadn't been for the warning, that shuriken would have incapacitated her, likely causing an injury that would have taken weeks to heal.
"Sarutobi Asuma! This is a one-on-one duel. Any outside warnings are forbidden! If you interfere again, Yuhi Kurenai will be disqualified immediately!" Aizawa-sensei warned Asuma sharply. The teacher was clearly furious, showing no regard for Asuma's status as the Hokage's son. This should have been a match-ending blow, but because of the interference, it had turned into a negligible scratch!
"Yes, sensei." Asuma hung his head obediently. He knew he had messed up. Seeing Kurenai about to get hurt, he had shouted out before he could even think.
A move that should have decided the match had only resulted in a trivial graze; that was entirely Asuma's fault.
To have two shuriken fly in an absolutely synchronized trajectory while utilizing the Shadow Shuriken technique was a feat far beyond the skill level of an average student. These were small shuriken, less than ten centimeters in diameter, not the massive Demon Wind Shuriken!
Kurenai checked her wound. It was just a graze, not serious. What was serious was her right hand; even now, the hand holding her kunai was still numb.
In an instant, she deduced the trick behind Hagoromo's attack.
"You coated the shuriken in Lightning Style?!" Kurenai asked in shock. There were only a handful of students in the entire Academy who could competently use Nature Transformation. More importantly, she was certain that Hagoromo hadn't performed any hand seals since the start of the match. So the question was: how did he use Lightning Style?
Hagoromo shrugged, offering no answer.
"And those small shuriken... how did you manage a Shadow Shuriken with those?" she asked, unwilling to let it go.
This time, Hagoromo answered, mainly because his "soul of a science lecturer" was burning.
"Making two small-volume objects perform synchronized motion on a wide arc, while maintaining acceleration for a final burst, is indeed difficult. It involves magnetic force, magnetic declination, and corrections for the Coriolis effect. I've summarized it into a rather complex formula, though using it in practice is a bit of a challenge for the brain's computational capacity..."
"Magnetic...?" For Kurenai, the explanation was worse than no explanation at all. That pile of terms she had never heard of made her head swim.
"From a physics perspective, a magnetic field is an electric field. Electricity and magnetism are inseparable. Or rather, electricity is magnetism, and magnetism is electricity. Lightning Style, to put it simply, is just the application of electromagnetism."
Kurenai: "..."
Teacher: "..."
Students: "..."
Everyone's internal monologue was screaming: What the hell are you talking about? Why don't we understand a single word?!
Then, they began looking at each other's reactions. Someone was nodding continuously—did he actually understand?
To avoid looking stupid, everyone else began nodding along as well.
"Gai, do you understand what Hagoromo means?"
"Huh? Me? ...Of course I understand! Why, do you need me to explain it to you?"
Gai wasn't exactly sharp, and he often acted like a "rare beast," but nobody wanted to be the fool in the room.
After staring deeply at Obito for a moment, Gai said, "No, no need for an explanation. I think I understand too."