Time passed, and the seven-day vacation was over in the blink of an eye.
Under Naruto's patient guidance over those seven days, Sasuke had made considerable progress in precise chakra control, though he was still far from meeting Naruto's standards.
Still, that level was enough to learn the Rasengan.
That evening, right after dinner, Naruto carried a wooden bucket in each hand and led Sasuke out of the courtyard.
Sasuke looked curiously at the two buckets Naruto was carrying. One held water, with a huge syringe used for injecting pigs floating on the surface, while the other held a large number of uninflated balloons.
"Naruto, why did you buy so many balloons?"
Curious, Sasuke took out a balloon and examined it. It was tiny, only about palm-sized when inflated.
"Well, to teach you how to play with water balloons properly."
Naruto smiled as he explained.
"W-what are you talking about? Playing with water balloons? I'm not playing such a boring game," Sasuke said unhappily.
"Hehe, these aren't just ordinary balloons. This is a training method. Listen to me. If you can do what I ask, I guarantee you'll learn an A-Rank ninjutsu with incredible destructive power."
At the mention of ninjutsu, Sasuke visibly perked up and asked, "What nature does it use? Fire Release or Lightning Release?"
Naruto shook his head. "Neither. It's a natureless ninjutsu. But once you've mastered it, you can develop it further and add your own chakra nature."
"A natureless A-Rank ninjutsu?" Naruto had thoroughly piqued Sasuke's curiosity. He grabbed Naruto's hand and pleaded, "Can you tell me the name first this time? Naruto..."
Honestly, even after more than five years together, Naruto had rarely seen Sasuke plead with him like this.
"Uh, sure. But for various reasons, don't tell anyone else its name for now."