Main world.
Summer, Year 18 of Konoha.
Konoha, Senju Clan Compound.
Summer sunlight filtered through the lush leaves, casting dappled light and shadows across the flagstones. The cicadas' cries rose and fell, mingling with shouts from the distant training ground to form the distinctive backdrop of the Senju Clan Compound. Ten-year-old Little Tsunade sat beneath the eaves, holding a thick medical book, her golden ponytail swaying gently in the breeze.
Beside her, Sakura Haruno wore a plain white kimono and patiently explained the book's contents.
"Here is the distribution of the liver's chakra network."
Sakura Haruno's finger traced lightly across the page.
"The liver's chakra channels are different from the kidneys'. The liver leans toward yang, while the kidneys lean toward yin. So, when treating liver injuries, you need to use yang release chakra. When treating kidney injuries, you need to use yin release chakra."
Little Tsunade nodded, her gaze focused.
"Then... what if both the liver and kidneys are injured?"
"Then you need to use both yang release and yin release chakra."
Sakura Haruno's voice was calm.
"But you must pay attention to balance. Too much yang will damage yin. Too much yin will damage yang."
"Balance..."
Little Tsunade repeated the word softly.
"Yes. Balance." Sakura Haruno nodded. "The core of medical ninjutsu isn't 'healing,' but 'regulating.' Regulating yin and yang, regulating qi and blood, regulating the chakra network. Once everything is properly regulated, the body will repair itself."
A glimmer flashed in Little Tsunade's eyes.
"Teacher, you're amazing."
The corner of Sakura Haruno's mouth twitched slightly.
Teacher.
Little Tsunade was calling her teacher.
Yet in another world, she called Little Tsunade teacher.
"Teacher, what's wrong?"
Little Tsunade tilted her head and looked at Sakura Haruno.
"Nothing."
Sakura Haruno shook her head.
"I'm just... feeling a little reflective."
"About