"What about me? What about me?"
Naruto Uzumaki eagerly pressed on. Sasuke and Sakura's numbers both had meanings, so he was curious what his own "three" stood for.
Wu Yu scratched his head. "Um—Chakra—a team with a ton of it?"
"What was that? You just made that up, didn't you?" Naruto Uzumaki grabbed Wu Yu by the shoulders and started shaking him.
Sakura Haruno also complained, "If it's a team with a ton of Chakra, Karin doesn't have any less than Naruto."
Shaken so hard his voice wobbled, Wu Yu said, "That's because—her constitution is special—her Chakra isn't actually all that much—"
The Uzumaki Clan's red hair signified powerful vitality, but strong vitality did not necessarily mean an enormous amount of Chakra. Before Karin was modified by the Slug, she had been like this, with only around 7 Stamina and Chakra Reserves. That was certainly a great deal compared to ordinary people, but it was only the equivalent of 2 Itachis—not enough to call it an extraordinary amount of Chakra.
A ninja's physical strength could roughly be divided into three parts, much like diving. The shallowest layer was [physical strength] in the conventional sense. When ninjas refined Chakra in their daily lives, they converted this portion of their physical strength. On the other hand, physical strength could also be used entirely for purely muscular Taijutsu. When Rock Lee did not open the Eight Inner Gates Formation, this was his style.
Once this visible physical strength was exhausted, one would be exhausted in the usual sense and could recover by eating, resting, and sleeping. But if the battle was not over and they had no choice but to keep refining Chakra, they would begin converting the deeper, middle layer of [latent physical strength].
Beneath the middle layer lay the deepest layer: