But he did not refuse.
He happened to need a strong enough opponent lately to test the practical effects of his Lightning Mode, swordsmanship fundamentals, and Lightning Ball practice.
The ordinary students at school were not up to the task.
Might Guy was suited to Taijutsu training, but this was not yet the time to reveal his lightning abilities casually.
Kakashi was different.
This guy was a recognized genius, with quick reactions, strong Swordsmanship, and combat awareness far beyond his peers.
He was just right for testing moves on.
Fang Xu reached into his Ninja Tool Pouch and took out a kunai.
Kakashi watched him.
"Not using Lightning Ball?"
Fang Xu tightened his grip on the kunai.
"Depends."
Kakashi lowered his short sword slightly.
"Then I won't hold back."
Lightning began flowing through Fang Xu's body.
Rather than erupting crudely throughout his entire body, it followed the method he had refined over the past few days, focusing on activating his ankles, calves, lower back, shoulders, elbows, and wrists.
Fine arcs lit up beneath his skin, and blue-white sparks crawled along his arm onto the kunai.
Lightning Mode activated.
Kakashi's exposed eye instantly grew serious.
"As I thought."
The next instant, arcs blasted black specks into the dirt beneath Fang Xu's feet.
He shot forward, his speed even more abrupt than an ordinary Body Flicker.
His kunai thrust straight at Kakashi's chest.
Kakashi raised his short sword horizontally.
Clang!
The clash of metal rang out.
The kunai and short sword collided, scattering sparks mixed with electric arcs.
Kakashi's arm went numb. He immediately turned sideways to redirect the force, his short sword following through with a diagonal cut toward Fang Xu's wrist.
Fang Xu shifted his footing. Lightning stimulated his calves, forcing his body half a beat faster.
The blade skimmed past his cuff.
He pressed his kunai down with a reverse grip, going straight for Kakashi's shoulder.
Kakashi retreated half a step and swept his short sword upward.
Clang, clang, clang!
They exchanged three blows in the blink of an eye.
Kakashi's Swordsmanship was steady, every block positioned to expend the least effort.
Fang Xu's bursts were faster, and Lightning Mode kept pushing his attack speed higher.
"It's more refined than it was in the alley."
Kakashi spoke quietly.
Fang Xu turned the kunai in his hand, electric arcs dancing over it.
"You're tougher to deal with than I expected, too."
Kakashi said nothing more.
He suddenly drove off his feet, sliding his short sword past Fang Xu's kunai and striking the back of the blade straight toward Fang Xu's ribs.
Lightning flashed across Fang Xu's lower back. He bent sideways to evade while driving his knee upward, forcing Kakashi to draw back his sword to block.
Thud!
The knee strike hit the flat of the short sword.
The impact drove Kakashi back a step.
Fang Xu gave him no chance to open up the distance. He burst forward again, pressing in amid sparks and lightning.
Kakashi raised his short sword horizontally and advanced instead of retreating.
The kunai and short sword collided again. A piercing metallic clang erupted alongside lightning as the two figures became thoroughly entangled in the middle of the riverbank.
Clang!
The kunai and short sword collided once more.
Arcs burst along the metal edges. Kakashi's wrist dipped, and his feet immediately slid half a step back.
Instead of pursuing with brute pressure, Fang Xu planted his right foot and, aided by the stimulation of Lightning Mode, shifted half a foot sideways. His kunai swept upward from below, aimed straight at Kakashi's sword wrist.
Kakashi turned his short sword and pressed its spine down.
Clang!
Another crisp ring sounded.
Fang Xu's kunai was forced aside, and the blade followed through, slicing along his arm.
This strike was fast.
Against an ordinary student, it would already have cut the arm open.
Lightning flashed at Fang Xu's lower back. His entire body jerked backward as though pulled by a thread, and the blade passed along his sleeve, cutting away only a small scrap of fabric.
Kakashi's eye widened slightly.
"You're not just using a kunai."
Without stopping his footwork, Fang Xu delivered a reverse diagonal slash.
"You noticed?"
Kakashi blocked with his short sword held horizontally, the impact numbing his arm.
"That's Kendo's way of generating power."
His tone was considerably more serious than before.
"You've studied the sword, too?"
Fang Xu did not answer. His kunai slid along the edge of the short sword as he pressed forward, his shoulder, elbow, and wrist exerting force together. He wielded that little kunai with the form of a short sword's cleaving slash.
Kakashi dared not be careless.
He had thought Fang Xu relied on Lightning Mode's explosive bursts.
But only after actually exchanging blows did he discover there was more to it.
Fang Xu's close combat was not the wild stabbing and blocking common among Ninja Academy students.
His footwork followed lines.
His attacks followed paths.
Every attack contested distance, and every retreat preserved an angle for a counterattack.
His movements were not smooth enough yet, and there were plenty of flaws in the details, but the framework was already in place.
He had grasped the basics.
Kakashi was somewhat surprised.
Fang Xu had clearly been only average at school before.
Lightning Mode could be explained as something he had developed after suddenly awakening his lightning attribute.
But what about Kendo?
Kendo was not so easy to hide.
Whether someone had practiced became apparent the moment blades met.
Clang, clang, clang!
They exchanged several more blows in the blink of an eye.
The short sword was longer, and Kakashi's Swordsmanship was steadier.
The kunai was shorter, but Fang Xu forced his speed higher with Lightning Mode.
For a time, the riverbank was filled with the clash of metal.
Grass was crushed beneath their feet, and charred footprints kept appearing in the dirt.
Fang Xu's right arm was numb.
Kakashi was not faring well either.
Every time the short sword struck the kunai, tiny currents of lightning traveled along his blade. Although they were not enough to immobilize him, they numbed his fingers and slowed his reactions by half a beat.
That half beat was deadly in close combat.
Dozens of meters away.
Up in a large tree, Hatake Sakumo stood in the shadows of the branches and leaves, quietly watching everything.
He made no sound.
He had been following farther behind ever since Kakashi began following Fang Xu.
As Kakashi's father, he had no objection to his son proposing a spar.
But even a spar between children needed someone watching to keep it within bounds.
Especially since Fang Xu had been changing so quickly lately.
Hatake Sakumo also wanted to see for himself just how far Naoto's child had come.
What he saw surprised him somewhat, too.
"Lightning-Attribute Nintaijutsu, Lightning Release Ninjutsu, and Kendo."
Hatake Sakumo's gaze settled on the kunai in Fang Xu's hand.
A kunai was not a sword.
It was too short and too light to fully execute many Kendo techniques.
But every turn of Fang Xu's wrist, every pressing step, and every withdrawal of force bore clear traces of Kendo.
He had not been learning haphazardly.
He really had reached the threshold.
His foundation isn't deep, but he's headed firmly in the right direction.
Hatake Sakumo quickly formed his assessment.
His timing is still immature, and his judgment of distance is off, but the way he generates power is already correct.
If he really is self-taught...
His gaze grew a little more serious as he looked at Fang Xu.
Then that was quite remarkable.
Grasping the basics of Kendo was nothing earth-shattering.
But for a Ninja Academy student without a teacher's guidance to reach this level through his own practice showed a high aptitude for understanding.
Especially since Fang Xu was not practicing only the sword.
He was also practicing Lightning Mode, Lightning Release, and the Three Body Technique.
Even with his efforts divided, he had managed to grasp the basics of Kendo.
That talent was already enough for Hatake Sakumo to take him seriously.
With a renowned teacher to hone his skills, he won't do poorly in Kendo in the future.
In the middle of the riverbank, the fight continued.
Kakashi suddenly sped up.
His short sword slid along the kunai, its tip circling around the front to cut straight toward Fang Xu's shoulder.
The angle of this strike was extremely tricky.
Fang Xu was just about to block with his kunai when he realized the short sword was only a feint.
The real attack was Kakashi's knee strike as he closed in.
Thud!