"Best of three sets! The Second-String Select team serves first!"
When Inui Sadaharu and Yanagi Renji made those comments during the coin toss just now, it was clearly aimed at messing with the Mutsu brothers. But judging by their blank expressions, it was hard to say whether it worked.
Standing behind the baseline, Inui Sadaharu had a flood of data flashing through his mind—everything from the Mutsu brothers' hitting habits to their behavioral logic. Of course, he hadn't forgotten their core foundation—Synchronization.
He tossed the tennis ball high, tilted his body back, used the motion of his waist and abs to channel all his strength into his right arm, then slammed his racket down hard onto the descending ball.
In an instant, the tennis ball turned into a rushing waterfall and blasted into the backcourt. The Mutsu brothers didn't react in time, and the ball shot straight out of bounds.
"Waterfall!"
"Ace! 15-0!"
"Serve speed: 237 km/h! Not bad at all—what do you think, Ochi?" Mitsuya smiled as he turned to ask.
"Probably not his limit yet. With that kind of serve speed, the Mutsu brothers will adapt soon," Ochi replied coolly.
"Nice serve, huh~ onii-san!" Yūho called across the court.
"But still not quite on Ochi's level. Think you can return it, Yūho?" Yūma replied calmly.
"Let's see~" Yūho didn't give a straight answer, only something vague.
Inui showed no change in expression after scoring. He casually picked up another ball, tossed it again, and launched another powerful and fast Waterfall.
"Ace! 30-0!"
Yūho still didn't move from his spot, letting the ball fly past. Truthfully, he had already seen the serve's path, but the speed was just too high—he didn't feel confident he could catch it.
"241 km/h! Just as expected, another small increase!" Mitsuya grinned while watching Inui. Based on his data, Inui's Waterfall could hit over 250 km/h at its peak.
Seeing the lack of reaction again, Inui didn't ease up. His third serve pushed both power and speed up a notch. Yūho looked completely unresponsive, standing still like a statue.
"Ace! 40-0!"
Inui's fourth serve was still Waterfall, but this time he cranked it to the max. The ball speed shot past 250 km/h. A flicker of sharp light flashed in Yūho's eyes, and Yūma's lips curved slightly into a smile.
"Game! Second-String Select! 1-0!"
"Should be about time now, right, Yūho?" Yūma asked with a composed look, unbothered by losing the first game.
"Ah~ It's pretty much what I expected, onii-san," Yūho replied with the same coolness.
"Then let's begin." Yūma looked at Yūho, and the moment he spoke, a milky-white aura rose from both brothers' bodies and instantly linked them together.
"Synchronization!"
Yanagi Renji wasn't surprised to see the faint golden glow in the Mutsu brothers' eyes. He had already predicted they would enter Synchronization in the second game. It was something he and Inui had simulated during their pre-match analysis.
"Synchronization, huh? In the end, it's just a form of entropy release," Yanagi murmured softly.
"Renji," Inui called from behind.
Yanagi nodded in response.
The second game was Yūma's serve. The Mutsu brothers didn't have any flashy serve techniques, just solid high-speed serves with nasty angles.
"This one has a 74% chance of landing near the left sideline," Inui suddenly said, predicting the serve's location. He was already moving to intercept.
He quickly returned the ball, continuing to speak as he moved.
"Yūho-senpai has a 91% chance of returning it. 86% chance it'll be a down-the-line passing shot!"
Sure enough, Yūho dashed in and struck a sharp drive down the line, but just as it looked like it would go through, a racket appeared in its path.
"100% chance of intercepting it at the right centerline. 79% chance of scoring with a drop shot," Yanagi called out, cutting the ball with a light slice.
The ball floated gently over the net and dropped down softly. Yūma slid forward to catch it, but the ball didn't bounce. Instead, it rolled oddly forward and stopped.
"Utsusemi!"
"0-15!"
"Nice one, Yanagi-senpai! Inui-senpai!" Kirihara cheered from the bench.
"Ugh… Data tennis really is annoying~" Yūho said quietly.
"Too bad the data they gathered might not even be useful. With Mitsuya around, like we'd leave that gap unguarded!" Yūma replied casually.
Yūma fired off another high-speed serve. Inui Sadaharu again predicted the landing spot and returned the ball with a backhand, immediately starting to predict the opponent's next move.
"Lob probability: 17%. Crosscourt shot probability: 81%. So... what?!" Mid-sentence, Inui suddenly froze.
Across the net, Yūho had mimicked Yanagi Renji's earlier move and dropped a short ball. Neither Yanagi nor Inui had seen it coming. They could only watch helplessly as the ball slowly landed—too far gone for either to reach in time.
"15-15!"
"In data tennis, the most important thing is the accuracy of your data. Did you really think you had all of ours?" Yūho said coldly after scoring, staring straight at Inui and Yanagi.
"A data tennis player's most basic discipline is to always hide their real data." Yūma chimed in right after.
From that point on, Inui and Yanagi's data became completely useless. All the info they had collected was what the Mutsu brothers had deliberately leaked. While not exactly fake, it still veered far from their true tendencies.
"15-30!"
"15-40!"
"Game! Japan Team! 1-1!"
"Without data, you two pose no threat to us at all! In the world of doubles, whether you're synchronized or not makes all the difference!" After tying the score, the Mutsu brothers spoke in unison again.
Still, Yanagi and Inui remained calm. They had expected things wouldn't go smoothly. Faulty pre-match data was already part of their prediction model.
Yanagi silently returned to the baseline. He gave the Mutsu brothers a glance before launching a high-speed serve and kicking his brain into overdrive to gather real-time opponent data.
From there, the match completely shifted to the Mutsu brothers' rhythm. With Synchronization activated, they were almost impossible to fight head-on. Inui and Yanagi tried to hang in there with sheer willpower but couldn't stop the point loss.
"Game! Japan Team! 2-1!"
"Game! Japan Team! 3-1!"
"Game! Japan Team! 4-1!"
In the blink of an eye, the Mutsu brothers had taken four games. It looked like the match was already decided. But both the twins and Mitsuya on the sidelines knew—it was only just beginning.
The hardest part about data tennis is that your opponent doesn't just study you beforehand—they can collect data during the match and adjust in real time. Unless you have overwhelming strength to end the match quickly, the longer it drags out, the higher the chance you get overturned.
The Mutsu brothers clearly understood this too, so they kept ramping up the pressure. With Synchronization activated, their coordination was flawless. And because they were twins, their mutual response was even smoother than most synchronized pairs.
Watching from the sidelines, Oishi, Kikumaru, Hiyoshi, Oshitari, Marui, and Jackal all gained a deeper understanding of Synchronization. Tachibana and Chitose didn't count—forget their special Synchronization—for pure individual strength, they far outclassed the Mutsu brothers.
"Game! Japan Team! 6-1! First set goes to Japan Team! Overall score: 1-0!"
Yanagi and Inui quietly left the court and returned to the coach's bench for water. That's when Akashi spoke up.
"Should be enough data by now, right? But can you be sure what you have this time is accurate?"
"Don't worry, Akashi-kun! Gathering data was just the prep work. We know better than to think we can win with data alone," Inui said, wiping the sweat from his face.
"Victory comes from reaching the opponent's essence through data. Like Mitsuya-senpai said, data isn't just for gathering—it's also for input and output!" Yanagi added.
"Then go again. Show me your data tennis," Akashi said coolly, giving a nod.
The second set started quickly. This time, Yūho was serving. Just as he walked to the baseline, Yanagi suddenly spoke.
"Humans are actually low-entropy creatures. So we subconsciously try to increase entropy. But in contrast, we're very inefficient at releasing it."
"Which means most humans have a dormant form of power within. The clearest example is mental force," Inui added.
"And talented tennis players use special methods to release that entropy. Whether it's Ten'i Muhō no Kiwami or Divine Path of the Asura, it's all the same principle," Yanagi continued.
"When two people match frequencies during entropy release, it forms a special positional channel. That's the true nature of Synchronization," Inui concluded, a sharp glint flashing across his glasses.