"Don't joke with us. We're not data tennis players—how could we possibly collect your data?!" Yūho said, clearly in disbelief.
"You just don't understand the essence of Synchronization. Even if you've both developed it to a very advanced level," Yanagi replied calmly.
The Mutsu brothers frowned deeply at that. They still couldn't believe what the other two were saying. When it came to Synchronization, there were few who understood or developed it better than them. They had even given up honing their tennis skills to dedicate themselves fully to mastering Synchronization.
"Strategy, calculation, simulation, prediction—all of it is based on data. The Mutsu brothers might've developed Synchronization to the level of instinct, but they still can't grasp its essence through data," Mitsuya said from the player bench, shaking his head lightly.
Yūma stood grimly at the baseline. He and his brother didn't cancel their Synchronization—it was the core of their doubles play. He believed that if they ignored those strange visions in their minds and focused hard enough, they could still hold their own.
As Yūma's thoughts transmitted to Yūho through their Synchronization, their energy surged violently. Gradually, the aura around them shifted from simple connection to complete fusion, fully wrapping both brothers in it.
"You think we'd abandon Synchronization over something this minor? You seriously underestimate us!" Yūma snapped coldly, tossing the ball high and smashing it down with a powerful swing. The ball rocketed across the court, far faster than before.
"Serve speed increased 32%. Right baseline probability: 79%. Data correction 7%," Yanagi muttered as he moved early to intercept the ball. But even he looked slightly surprised—Yūma's serve was clearly faster than his previous calculations had shown.
Fortunately, the target zone hadn't shifted much. Yanagi grew alert and started recalibrating the data with Inui. The Mutsu brothers had clearly entered a deeper level of Synchronization.
As Yanagi returned the serve, Yūho's movements became noticeably quicker. The match suddenly erupted into fierce exchanges. The Mutsu brothers occasionally froze for an instant, but their improved focus allowed them to barely keep up.
The score bounced back and forth. On the surface, it looked evenly matched. But inside, the Mutsu brothers were growing anxious. They knew better than anyone—data tennis thrives in drawn-out battles.
"Game! Second-string selection! 3-0!"
"Game! Japan team! 3-1!"
"Game! Japan team! 3-2!"
"Game! Second-string selection! 4-2!"
"Game! Second-string selection! 5-2!"
Sure enough, Inui and Yanagi gradually took control of the match again. Without realizing it, they had gained a massive lead. One more game, and they'd win the second set.
Yanagi was up to serve. Standing at the baseline, a faint smile crept onto his face. Inui, up front, wore a more obvious grin—like everything was going exactly as planned.
"Data construction complete," Yanagi murmured softly, then served. The speed and angle seemed totally ordinary, and Yūma looked a little confused.
But he wouldn't miss such an easy chance. He dashed to the landing spot—then suddenly, his thoughts collapsed. His mind was flooded with just two numbers: 0 and 1. The ball zipped right past him and bounced out.
"Ace! 15-0!"
Luckily, that mental crash only lasted under 2 seconds. Yūma quickly snapped back to his senses. At the same time, Yūho recovered from his daze. Because of their Synchronization, both had fallen into that moment of thought collapse together.
From the bench, Mitsuya instantly understood what had happened on court. His smile widened. Both Yanagi and Inui could be considered his protégés—but their growth had already exceeded even his predictions.
"They actually performed data output against non-data-type players? Amazing. Though... maybe we should thank the Mutsu brothers for their 'cooperation'~," Mitsuya chuckled.
While the Mutsu brothers were still trying to process what had just happened, Yanagi served again. Yūma had no choice but to force himself to focus and rush to the drop point. But this time, the mental crash hit even harder. In mid-run, he stopped suddenly, a blank look in his eyes. The ball smacked the backcourt and bounced out.
"Ace! 30-0!"
Yūma shook his head hard, eyes fixed tightly on the two across from him. His tone turned sharp.
"What the hell did you two just do?!"
"To be precise, we didn't do anything extra. Like we already explained—we just transmitted our own data to you," Inui Sadaharu adjusted his glasses as he replied.
"You two raised the depth of your Synchronization. But at the same time, the scope of the stance channel also expanded. In other words, the amount of data you can now receive has increased—even if that wasn't your intention," Yanagi Renji added from the backcourt.
"Using the Mutsu brothers' own Synchronization to restrain them… that's something only you two could pull off," Akashi Seijurō, seated at the coach's bench, showed a rare smile as he spoke.
Of course, the Mutsu brothers refused to accept Inui and Yanagi's explanation. They stubbornly held onto their Synchronization, but the result didn't change. Yūma was still powerless against the cognitive collapse triggered by Yanagi's serves, helpless as the ball flew past.
"Ace! 40-0!"
"Game! Second-string selection! 6-2! Second set! Second-string selection wins! Match total: 1-1! Now beginning the final set!"
During the break, the middle school players all cheered for Inui and Yanagi, but the two remained calm. So far, the match had gone exactly as they predicted—but they couldn't afford to let their guard down.
Over on the high school side, Mifune watched Inui and Yanagi with interest, then turned toward the Mutsu brothers.
"You two aren't planning to use your trump card? If this keeps up, you're gonna lose~"
The Mutsu brothers didn't respond, remaining silent. Mifune didn't mind. He knew full well the potential those twins held. The only reason they were ranked 15 and 16 was because the ranking matches were mostly singles.
But in doubles, they were definitely top-five level. If they fully unleashed their trump card, not even Byoudouin with his alternate dimension could beat them quickly. Mifune was genuinely looking forward to seeing how the third set would unfold.
Soon, the final deciding set began. The Mutsu brothers kept their deep-level Synchronization, but under the pressure of Inui and Yanagi's data attacks, their movements became more and more rigid.
"Game! Second-string selection! 4-0!"
Under this continued disadvantage, the Mutsu brothers quickly lost four games in a row. It looked like they had given up. But only Mifune and the top ten from the first-string knew—they were likely preparing to unleash their final trump card.
The fifth game was Yūho's serve. Just then, the two brothers exchanged a glance and nodded at each other. Their Synchronization aura began surging rapidly, and all of it gathered around Yūho, while Yūma stood silently at the net.
This sight made Inui and Yanagi frown. None of their collected data or material mentioned anything like this. They both instantly grew alert, hyper-focused.
Yūho tossed the ball high, and with a sharp swing of his racket, it slammed into the court behind Inui before he could even react.
"Ace! 15-0!"
"Wh… what?! That serve completely exceeded my data!" Inui turned back in disbelief. A lone tennis ball rested motionless by the fence.
"Serve speed… 261 kilometers per hour…" Yanagi reported calmly.
"Oh? Looks like they've started," Mōri said with a grin as he glanced at Ochi beside him.
"That's already around 60% of Ochi's Mach-level serves~" Kimijima added, smiling too.
"This… to think they've reached this level... interesting," Akashi's eyes sparkled as he activated most of the Emperor Eye's abilities, sounding genuinely impressed.
Ignoring the crowd's reaction, Yūho tossed another serve. Even though Inui now used data to predict the landing spot and moved early, he still couldn't catch up. The ball sliced past and bounced out.
"Ace! 30-0!"
"Ace! 40-0!"
"Game! Japan team! 4-1!"
"Mutsu Yūho-san's serves can't possibly reach that speed. They must've done something beyond what our data accounts for!" Inui said seriously after losing the game.
"Ah... it's probably a more advanced application of Synchronization by the senpai. But we just can't see through the essence of it yet," Yanagi replied with a furrowed brow.
Next came Yanagi's service game. He and Inui kept using data pressure to momentarily disrupt Yūma's mind. But to their shock, while Yūho did fall into a daze, Yūma moved without any hindrance.
"0-15!"
"Using the unique qualities of Synchronization to counter us… that's something we hadn't considered. But too bad—for Synchronization mastery, we've already gone beyond your data," Yūma said calmly after scoring.