Naruto: They Have Systems

Chakra Paper, as its name suggested, could test the nature of a Ninja's Chakra.

Fire: the paper caught fire.

Wind: the paper split down the middle.

Lightning: the paper wrinkled.

Water: the paper got wet.

Earth: the paper crumbled.

Uchiha Yin's result meant that he currently possessed Chakra of four natures—fire, lightning, water, and earth. It was far beyond anything Uchiha Mikoto had expected.

As far as Uchiha Mikoto knew, most Ninjas possessed Chakra of only one or two natures when they were young.

Only after reaching the level of Jonin could they learn ninjutsu of natures their Chakra did not originally possess and gain those new natures.

Even then, newly acquired natures were not as strong as their original ones. Most Ninjas therefore trained their innate Chakra nature to its peak and learned the others only as backups.

Kakashi, for instance, was born with Lightning Nature. He had copied techniques of other natures with his Sharingan.

In battle, he tended to use Lightning Nature ninjutsu.

Uchiha Yin, on the other hand, was "born" with Chakra of four natures. He was a genius.

Of course, Uchiha Yin had not actually been born with all four. His original Chakra natures should have been fire and lightning, the standard combination for the Uchiha Clan. Not long after he became Tsunade's apprentice, the system had suddenly rewarded him with Water Nature and Earth Nature Chakra.

Uchiha Mikoto knew nothing about that, of course, so she assumed he had possessed all four natures from birth.

"All I'm missing is wind, and I'll have every Chakra nature."

Uchiha Yin looked at the Chakra Paper in his hand and muttered to himself.

"Four Chakra natures are already incredible. I've never met anyone with that many before."

Seeing that Uchiha Yin still seemed dissatisfied, Uchiha Mikoto gently