"Now that we've tested your affinities, we'll move on to the next exercise."
The Land of Rain was crisscrossed with rivers and dotted with swamps. If you couldn't fight on the water as easily as on solid ground, you'd be a sitting duck.
"Tree climbing uses a steady flow of Chakra to cling to a fixed surface, but Water Walking..."
Uchiha Fugaku stepped forward and stood steadily on the restless water.
The current rushed beneath his feet, but he was as firmly planted as if nailed in place, unmoving despite the waves.
"Water is constantly moving and has no fixed shape. You must continually adjust the amount of Chakra you release through your feet to adapt to changes in the water's surface."
He looked at the two of them. "You have to learn this."
"Yes."
Namikaze Minato watched the river beneath his feet, a thoughtful glint in his blue eyes.
He tentatively extended one foot and lightly touched the water, feeling the current push against it.
"I see. You don't grip it—you support yourself on it..."
The next moment, Namikaze Minato was standing on the water.
At first, he wobbled a little, like someone walking a tightrope. But after just ten minutes, he was jogging across the water.
"..."
The notebook Nishikawa Tetsu had just taken out to calculate things was still unopened in his hands.
He glanced at Namikaze Minato, already running across the water, then at Uchiha Fugaku, whose expression had grown complicated.
So this is what they call a genius?
"Don't look at him. Look at the water!" Uchiha Fugaku's stern voice rang out. "If you haven't learned by nightfall, you're going without dinner."
Nishikawa Tetsu sighed and walked to the riverbank.
"Surface tension, fluid mechanics, buoyancy formulas..."
He began building a model in his mind.
"Unlike the static friction involved in tree climbing, this is a dynamic equilibrium. It doesn't require a constant output, but high-frequency, pulsed adjustments."
Splash!
On his first attempt, Nishikawa Tetsu stepped right through the surface and plunged halfway into the icy river.
"Too heavy," Uchiha Fugaku commented from the bank, arms crossed.
Splash!
On his second attempt, he released too much Chakra. The water exploded upward, and the recoil knocked Nishikawa Tetsu onto his back and into the river.
"Too stupid." Uchiha Fugaku furrowed his brows.
Nishikawa Tetsu spent almost the entire afternoon "bathing."
Only as the sun began to set, soaked through and shivering with purple lips, did Nishikawa Tetsu finally manage to stand on the water.
He still had to focus completely and couldn't move across the surface as easily as Namikaze Minato, but at least he no longer fell in.
"Barely usable."
Uchiha Fugaku glanced at the sky and tossed Nishikawa Tetsu a dry towel. "Back to camp. Get some rest."
Two in the morning.
The rain in the Land of Rain never stopped, a kind of natural white noise.
Inside the tent, Namikaze Minato breathed evenly. The intense training during the day had clearly worn him out, too.
But Nishikawa Tetsu suddenly opened his eyes.
As a researcher, he'd developed light sleeping habits and an irregular schedule in his previous life. A sudden urge to pee had just forced him out of his warm sleeping bag.
He got up as quietly as he could, only to find the bed at the far end empty.
"Fugaku?"
Nishikawa Tetsu glanced at the neatly folded blanket, puzzled.
Was Fugaku at Jiraiya's for a meeting, even at this hour?
Or was it...?
Nishikawa Tetsu put on his raincoat and slipped out of the tent.
By the dim light of the camp and a faint glimpse of moonlight through the clouds, he didn't head for the latrine. Instead, almost against his will, he made his way toward the rocky riverbank where they'd trained that day.
Before he even got close, a wave of scorching heat hit him, mingling with the cold, damp wind.
"Whoo—"
"Cough, cough, cough!"
A stifled coughing fit came from behind a boulder.
Nishikawa Tetsu softened his steps and peered out from behind a tree.
Uchiha Fugaku stood by the river, his back to the camp.
He wasn't wearing his signature high-collared Uchiha robe. Instead, he had on nothing but a tight black combat vest.
The Uchiha Young Clan Leader faced the river, forming Hand Seals.
"Compress it... compress it more..."
Uchiha Fugaku muttered under his breath, his voice edged with determination. "Like that kid said, increase the oxygen... something..."
"Snake—Ram—Monkey—Boar—Horse—Tiger."
"Fire Style: Great Fireball Technique!"
A burst of flames shot out.
At first they were the usual orange-red, but then Uchiha Fugaku puffed out his cheeks, seemingly trying to forcefully compress the Chakra in his mouth.
The flames contracted at once, their color beginning to shift toward blue.
But the change was wildly unstable.
"Pfft!"
A muffled bang.
Before the flames could turn completely blue, a cloud of black smoke burst from the corner of his mouth.
"Cough, cough! Cough!"
Choking on the smoke, Uchiha Fugaku coughed repeatedly. A cluster of blisters had formed at the corner of his mouth, leaving him looking rather pathetic.
"Damn it. The theory should work."
Uchiha Fugaku wiped the soot from the corner of his mouth, his eyes filled with stubborn defiance.
"Is the Chakra rotation too slow? Or is the timing of the mixture wrong?"
He took a deep breath and prepared to form Hand Seals again.
During the day, he'd only given the technique a quick try in front of his two juniors, wanting to maintain the Uchiha's aloof image.
But as a shinobi who sought power, he couldn't stop thinking about Nishikawa Tetsu's theory of complete combustion. It nagged at him like a cat clawing at his heart.
Since he couldn't bring himself to ask for advice during the day, he'd had no choice but to practice in secret at night.
"Compression doesn't mean squeezing it with brute force, Fugaku."
A calm voice suddenly came from the woods behind him.
"Who?!"
Uchiha Fugaku jumped. His body tensed instinctively, a Kunai appearing in his hand as he spun around.
When he saw Nishikawa Tetsu standing beneath a tree with a calm expression, a succession of emotions flashed across his normally icy face: shock, embarrassment, irritation, and more.
He looked like a schoolboy caught secretly cramming by the class genius.
"What are you doing here?"
Uchiha Fugaku quickly put away the Kunai and tried to assume a dignified pose. But with his face covered in soot and blisters at the corner of his mouth, he wasn't very convincing.
"I'm just out on patrol. Right, patrol."
"Does patrolling require you to breathe fire at the river?"
Nishikawa Tetsu walked over. He wasn't mocking Fugaku; instead, he seriously pointed at his throat. "You're on the right track, but you're going about it the wrong way. You're trying to physically compress the Chakra with your mouth muscles, which causes it to backfire. You could easily burn your airway."
Uchiha Fugaku had been about to tell him to go back to bed, but when he heard the professional analysis, he swallowed his words.
He fell silent for two seconds, then awkwardly turned his head away. His voice was as quiet as a mosquito's buzz. "Then how should I do it?"
Nishikawa Tetsu chuckled to himself. This tsundere streak really is hopeless.
He picked up a twig and drew a simple spiral in the damp earth.
"Turbocharging," Nishikawa Tetsu said.
"You need to form a Chakra vortex in your throat and make the Chakra spin rapidly as it shoots out. The centrifugal force will draw in outside air, allowing the mixture to reach high pressure the instant it leaves your mouth. Don't hold it in there."
"Make the Chakra spin?"
Uchiha Fugaku studied the drawing on the ground, deep in thought.
"Give it a try. Don't hold your breath. Let it out with the force of the rotation."
Uchiha Fugaku nodded and formed Hand Seals again.
This time, he didn't try to squeeze the Chakra with brute force. Instead, he followed Nishikawa Tetsu's instructions, controlling it to form a spiral in his throat.
"Fire Style: Great Fireball Technique!"
"Vroooom—!!!"
A sound like a jet engine starting up rang out.
A pure, steady, tightly concentrated stream of pale blue fire shot across the river, instantly evaporating the water in its path and leaving a deep, glowing-hot hole in the rocks on the opposite bank.
No black smoke. No backfire.
Perfect.
Uchiha Fugaku gazed at the beautiful blue flames, excitement reflected in his eyes.
He'd done it!
The power had increased by at least twofold, while the Chakra cost remained the same.
He ended the technique and turned to look at Nishikawa Tetsu.
The two of them faced each other in the rainy night.
After a long moment, Uchiha Fugaku cleared his throat awkwardly. The soot on his face made him look a little ridiculous, but he did his best to preserve his dignity.
"Ahem... I just happened to refer to your suggestion while developing a new technique. I wasn't practicing your theory specifically."
"I understand," Nishikawa Tetsu said, playing along and giving him an out.
"As a genius of the Uchiha Clan, you practice late into the night and always strive to improve. That's something us juniors should learn from."
Uchiha Fugaku's expression eased a little.
He walked up to Nishikawa Tetsu and patted him on the shoulder, much more gently than he had during the day.
"About tonight..."
"I didn't see a thing."
Nishikawa Tetsu answered at once. "I just came out to use the toilet. It was too dark to see anything."
Uchiha Fugaku nodded with satisfaction, the faintest smile finally tugging at the corners of his mouth.
"Go back to bed. We have more training tomorrow."
"Yes."
Nishikawa Tetsu turned and headed back.
Just as he was about to enter the woods, Uchiha Fugaku's voice came from behind him. It sounded casual, but carried a hint of warmth.
"By the way, that Water Walking today..."
"You did all right. You weren't too embarrassing."
Nishikawa Tetsu paused. Without turning around, he simply waved over his shoulder.
Before you continue