"I don't really get what you're talking about, but even if you figured out what Synchronization is, so what?" Yūho said coldly.
"Yeah. That doesn't close the gap between us," Yūma added right away.
"No. Once you understand the essence of Synchronization, everything after that becomes simple. I just need to output my data to Inui in a specific way," Yanagi said calmly.
"And I just have to analyze the data I receive, then feed it back using my own data. In the end, we'll be able to..." Inui trailed off mid-sentence.
Just as the Mutsu brothers looked confused, a faint glow rose around Inui and Yanagi, connecting them. Even though their eyes didn't visibly change, massive streams of data flickered across them.
"Data Synchronization!" the two of them said in unison.
"No way... how are they doing that?!" Chitose stared at the court in disbelief.
"This is crazy. It's making me want to play too!" Tachibana Kippei said, also surprised.
"Does science lead to mysticism? This really wasn't something I expected..." Even Akashi was caught off guard that they achieved such a mystical state using such a scientific method.
"So all that talk just now was about some special kind of Synchronization, huh?" Yūho didn't take their so-called data Synchronization seriously. He tossed the ball and smashed out a high-speed serve.
"Right baseline corner: 76% probability! Data correction: 3%!" Inui called out as he dashed toward the predicted spot. The ball landed and bounced up just as he reached the baseline.
Inui countered with a forehand drive, the ball flying swiftly toward the middle backcourt. Yūma sidestepped left and reached the spot, but as he was about to return the shot, a chaotic series of bizarre images flashed through his mind—same for Yūho.
Although Yūma snapped back quickly, the ball was already inches away. He swung hastily, unable to aim properly. Before the ball even crossed the net, Yanagi was already waiting on the left sideline.
"Pause time: 0.54 seconds. Probability of sudden crosscourt shot: 96%. Angle deviation: 12%. Data correction: 4%!" Yanagi rattled off the numbers as he slashed at the bouncing ball with a sharp backhand.
The ball spun violently and darted diagonally across the court like a missile. It shot straight toward Yūma, who once again saw strange images—right before taking the ball full force in the stomach and getting knocked off his feet.
"Kamaitachi!"
"0-15!"
"Don't underestimate data tennis, senpai!" Inui and Yanagi raised their rackets together, calling out to the Mutsu brothers.
"You okay, nii-san?" Yūho rushed over, ignoring the taunts.
"I'm fine. Just hurts a little." Yūma stood up, rubbing his stomach.
"That's good... but you saw those weird images too, right? What were those?" Yūho asked, relieved but confused.
"No idea. But it's definitely got something to do with those two," Yūma answered as he walked back to his position.
"Strange. The Mutsu brothers looked sluggish just now. They blanked out when hitting the ball..." Irie muttered from the bench, frowning.
"That's some brilliant data application," Mitsuya said, sounding quietly impressed.
Yūho, now clearly angry, stepped to the baseline with a sharp glare at the two across from him. He tossed the ball high and smashed it hard with his right hand.
"Seeing his brother get hit, anger probability: 93%. Serve speed increase: 18%. But control drops: 53%. In other words, this serve's lost its calm," Inui said as he darted to the return spot.
Inui returned the serve. At the same time, Yanagi started moving toward his own left baseline. Yūma spotted it and let out a small scoff.
He rushed to intercept the ball, pretending to aim for a right-side drive. But then, the bizarre visions hit again. Snapping back, he had no choice but to awkwardly block it with a backhand. The ball popped up into the air, high and slow.
"Probability of reacting to Yanagi's movement with an opposite play: 89%. Action delay: 0.48 seconds. Resulting in a forced lob: 93%. My smash success rate: 100%!" Inui calmly recited as he leapt into the air and smashed down with full force.
The ball shot like a beam of light between the Mutsu brothers, slammed into the baseline, and flew out of bounds. Yūho had wanted to intercept it but didn't make it in time.
"0-30!"
"YEAH!!! Keep it up, Inui!" Kikumaru shouted from the stands, jumping with excitement.
"Ohhh~ Not bad, Inui-senpai!" Ryōma grinned and said proudly.
"Yanagi-senpai! Finish the match in one go!" Kirihara shouted excitedly.
This time, the Mutsu brothers didn't respond. But their expressions turned serious—despite all the misdirection and data manipulation they had done during the first set, their opponents still managed to calculate all of their actions.
"Data tennis? Don't mess with me!!!" Yūho growled under his breath and served again. But Inui had already locked onto his data completely, returning the ball with ease.
"You're wondering how we could collect accurate data even though you misled us during the first set, right?" Yanagi appeared near the net and spoke calmly to the Mutsu brothers.
"What?!" Yūho was startled by Yanagi's sudden words. Combined with the strange images flashing in his mind, his swing went off and he hit a straight shot.
"Straight shot probability: 96%! Angle deviation less than 0.5%!" Yanagi was already waiting on the other side. He quickly fired off a sharp backhand, hitting the ball into a visual blind spot between the brothers. By the time Yūma reacted, the ball had already bounced out of bounds.
"0-40!"
"Once we realize that the data we collected has misleading elements, we can reconstruct the correct model using auxiliary data and forward simulation," Inui said calmly from the baseline after the point.
"Normally, neither of us could do that alone. But with Data Synchronization, we can," Yanagi continued.
"I see... So Synchronization lets them process and simulate data simultaneously, doubling their computing power?" Mitsuya muttered thoughtfully from the bench.
"I'd rather die than play doubles with Inui-senpai..." Momoshiro mumbled in horror.
"I agree," Hiyoshi added with a grim look.
"Double data collection... I wonder if Closed Mind can withstand that..." Oshitari Yūshi frowned, thinking seriously.
By now, Yūho had served for the fourth time. But every move they made was already predicted by Inui and Yanagi. The returns were all under their control, and the Mutsu brothers could only watch helplessly as they lost the first game of the second set.
"Game! Second-string selection! 1-0!"
In the second game, it was Inui's turn to serve. Yūho had already managed to return his Waterfall serve in the first set, so he wasn't too worried—although that data prediction ability was still a huge problem.
Inui stood at the baseline. A ray of sunlight reflected off his glasses, hiding his eyes and thoughts completely. Then he tossed the ball and fired off a Waterfall serve with full force, the ball rushing like a column of water toward the opposite court.
"That move doesn't work on me anymore. Compared to Yukimura's serve, you're still way off!" Yūho said confidently. But a moment later, another bizarre image flashed in his mind, throwing off his timing.
"Ace! 15-0!"
"What the hell is that?!" Yūho muttered, confused.
"No... the question is what did they do to us..." Yūma said seriously.
Because of their Synchronization, both Mutsu brothers saw those strange visions—like strings of numbers or video clips. But the interference seemed heavier for Yūho this time.
"Ace! 30-0!"
As the brothers hesitated, Inui served another Waterfall. Just like before, Yūho was disrupted and failed to return it.
"Ace! 40-0!"
"Game! Second-string selection! 2-0!"
With just a few Waterfalls, Inui secured another game. The Mutsu brothers couldn't hold it anymore and shouted at Inui and Yanagi:
"What the hell did you do?! Why do we keep seeing those weird images?!"
"It's simple. We already explained it when the match started. Because of Synchronization, you've created a special connection—a transmission channel between your minds," Yanagi said calmly.
"In other words, during Synchronization, you subconsciously start collecting each other's data. We just amplified that data collection a little. The weird images you saw were simply unprocessed data that your brain couldn't keep up with," Inui explained.
"So, if you want it to stop, you'll have to break your Synchronization. But if you do that, your chances of beating us in our synchronized state are exactly 0%," Inui and Yanagi said in unison.