Rasengan

Kangetsu shifted his left foot slightly, then rapidly formed hand seals and shouted, "Body Flicker Technique!"

There are three types of Body Flicker: space-time ninjutsu, body-flicker taijutsu, and elemental-based techniques.

Kangetsu naturally couldn't perform space-time ninjutsu, he lacked the physical constitution for body-flicker taijutsu, and the elemental variety required hand seals to achieve instantaneous movement through material substitution.

The rapid hand seals Kangetsu was performing now were for an elemental technique.

Elemental Body Flicker techniques include the Sand Flicker, the Water Flicker, and so on.

Even the Body Replacement Technique is merely a simplified, cut-down version of the Body Flicker.

What Kangetsu was using now was the Water Flicker technique derived from Hanzo the Salamander. This type of Body Flicker does not require chakra of a specific nature; it only requires swapping places with water in the opponent's vicinity.

Kangetsu had already locked his gaze onto a pool of blood near Ishikura Kameda, and blood, after all, is water.

Thus, under Kameda's shocked gaze, Kangetsu appeared directly behind him.

At that moment, Kangetsu could still hear Kameda muttering, "I am invincible! I am impervious to blades and spears!"

Kangetsu merely offered a disdainful smile. In that instant, a swirling mass of chakra manifested in his left hand.

If Naruto from the original story were here, he would surely exclaim, "How do you know the Rasengan too?"

Indeed, this was the Rasengan—the very technique the Fourth Hokage had specifically created for Naruto.

The Rasengan is arguably the most practical ninjutsu in the Naruto world. Beyond the fact that it requires no hand seals and possesses considerable destructive power, it is also a technique that can be evolved further by adding elemental chakra.

Furthermore, the Rasengan's greatest strength is that it is easy to learn. To master it, the most important thing is understanding the principle behind the technique, followed by chakra control, the application of that chakra, and the ability to grasp the flow of battle.

It could be said that in the Warring States Period, once the principle of the Rasengan was known, it would be easily mastered. In this dangerous era, every drop of chakra is utilized with precision; not a single shred is wasted, as even a tiny amount could become the means to save one's life.

Therefore, it can be said that everyone in the Warring States Period was adept at chakra control.

With the principle understood and the necessary chakra control in place, was the Rasengan really that far off?

The drawback of the Rasengan is its offensive nature; despite its immense power, it is useless if it fails to strike the enemy.

Thus, the timing of its use and how to land a decisive hit are matters that require careful thought—a task that relies entirely on one's intellect.

Another disadvantage is the sheer volume of chakra required. A single Rasengan demands twice the chakra of a standard A-rank ninjutsu.

Kangetsu formed the Rasengan directly in his palm, but he could only manage one. His chakra reserves were limited to a single use; if he were to attempt another, the immense mental strain would drain his frail body until he was nothing but a husk.

Yet, at this moment, under the astonished gazes of Inoue and the others, Kangetsu shouted coldly, "Rasengan!"