After finishing with the Rasenshuriken, Naruto turned his attention to another research direction for the Rasengan, which was miniaturization.
When fighting specific enemies, the Rasengan is not always better the bigger it is.
Although a huge Rasengan has astonishing power, it simultaneously slows down the attack speed, and it is very easily noticed by the enemy.
If facing a speed-type opponent, a ping-pong ball-sized mini Rasengan would have faster speed while maintaining its power, and could surprise the enemy and penetrate their defensive line during close-quarters combat.
Under Absolute Control, Naruto repeatedly adjusted the compression ratio and rotation radius of the Chakra inside the Rasengan, attempting to compress a standard-sized Rasengan to only the size of a ping-pong ball without losing the internal rotation density.
This process was even more mentally taxing than developing the Rasenshuriken. Shrinking is harder than expanding because when Chakra is compressed to extreme density, it generates tremendous internal tension, and if one is not careful, it will dissipate.
Fortunately, there were enough Shadow Clones. The trial-and-error cost spread across two hundred Clones led to a breakthrough.
The high-density compressed Rasengan would only dissipate 5 seconds after being released, meaning that its range was as far as he could throw it within five seconds.
At the same time, Naruto also took the time to do an experiment, which was to integrate Lightning Chakra into the Rasengan.
He had an idea: if he attached Lightning Chakra to the Rasengan, could he develop an invisible Rasengan like Boruto's that could disappear into thin air after being thrown, and then suddenly reappear before the enemy could react?
Taking it a step further, if this vanishing characteristic were applied to the Rasenshuriken, an invisible and constantly cutting giant shuriken would fly toward the enemy. The enemy wouldn't even be able to judge where the attack was coming from and could only be beaten passively.
Of course, it was currently in the preliminary stage. The practice of Lightning Release nature transformation had only just been completed, and wanting to integrate it into the Rasengan to produce a stable and controllable nature mutation would still require time and experimentation.
The second harvest was the completion of his Lightning Release development.
Naruto chose to develop Lightning Release first because of the Rasengan, followed by the Flying Thunder God Technique. In certain application scenarios, he could use Lightning Chakra to increase his speed when performing the Flying Thunder God Technique.
Furthermore, Lightning Release is the attribute with the most prominent penetrating power and paralytic effect among the five basic attributes. In close-quarters combat, attaching Lightning Chakra to a Kunai can paralyze an enemy's local muscle groups, or even interrupt their hand seal movements.
After twenty days of repeatedly using Lightning Release: Lightning Flash, he now possessed the foundation to continue moving forward.
The third harvest was a further breakthrough in the Flying Thunder God Technique. He had grasped Flying Thunder God: Guiding Thunder.
Flying Thunder God: Guiding Thunder is the third stage of the Flying Thunder God Technique.
Unlike the first and second stages, which teleport oneself to a coordinate point where a technique formula was previously left, Flying Thunder God: Guiding Thunder teleports other entities or Ninjutsu away. Of course, the destination also requires a Flying Thunder God Technique coordinate.
Furthermore, Naruto was now able to perform the Flying Thunder God Technique in practical applications just like Minato.
In high-speed combat, the moment he makes contact with an enemy's body, he can imprint the Flying Thunder God Technique formula onto them. The formula then automatically hides itself, and unless he actively activates it, the marked person is unable to perceive it.
Naruto attributed this achievement to Fuinjutsu. It was precisely because Fuinjutsu helped him automatically apply a layer of stealth seal after the technique formula was engraved that the mark remained unperceived.
The fourth harvest was Fuinjutsu.
The Flying Thunder God Technique formula could achieve engraving upon hiding and hiding meant permanence, precisely because Naruto had combined Fuinjutsu and the Flying Thunder God Technique formula at a fundamental level.
He was now able to independently set up a Sensory Suppression Barrier without needing the cooperation of Clones. By simply performing specific hand seals in succession, he could create a Sensory Suppression Barrier, with the size of the barrier depending on the amount of Chakra injected.
In addition to this, he had also learned several practical Fuinjutsu, including short-term object sealing and Chakra suppression sealing.
However, the overall learning progress of Fuinjutsu was not particularly fast. After all, his main energy during this period was focused on the breakthroughs of the Rasengan and the Flying Thunder God Technique, so Fuinjutsu could only be considered supplementary training, and several high-level Fuinjutsu were still on the to-learn list.
...
At this moment, Naruto stood in place with both hands spread open.
On his right hand, a swirl of light green Wind Chakra rotated at high speed in his palm, emitting a faint cutting sound.
On his left hand, a swirl of light blue Lightning Chakra danced at his fingertips, with electric arcs crackling.
Two different attributes of Chakra were simultaneously condensed in his two hands, not interfering with each other and operating stably.
Naruto looked down at the two distinct clusters of Chakra in his hands, the corners of his lips curving slightly.
After the Chunin Exams ended, he could begin to research the fusion of Wind and Lightning Chakra.
Just at this moment, a familiar fluctuation approached at extremely high speed within his Negative Emotions Sensing.
Jiraiya had returned.
Naruto flipped his hands, dissipating both Chakra clusters simultaneously, then leaned against the rock wall, waiting quietly with his hands in his pockets.