Naruto: The Scientific Ninja

Chapter 35: Infrasonic Radar

After a full meal, Sasuke found an excuse and returned to his underground laboratory. Fortunately, Shibi had been sensible—or perhaps his detection range was limited—and had only distributed his parasite insects on the periphery of their defense zone, leaving the squad itself unmonitored.

When he arrived at the lab, Sasuke eagerly unsealed the scroll containing his new experimental equipment. It took him two full days to install everything. Once the lab was set up, he immediately took the bisected body of his water bat from its saline solution and began his anatomical research.

The results were gratifying, but the path forward was not smooth. The good news was that he had now basically deconstructed the bat's ultrasonic principle. The bad news was that while chakra was nearly omnipotent, it still followed the law of conservation of energy. To replicate the bat's meticulous physiological structure with chakra required a relatively high amount of both energy and control. Pushing the perception limit beyond three kilometers would cause the chakra requirements to increase exponentially. For practical combat purposes, the effective range of his sonar radar would have to be kept below two hundred meters.

Continuing to research in this direction is starting to have diminishing returns, Sasuke thought, a little disappointed.

However, there is always a silver lining.

As he reviewed the research materials on other summoned beasts, he found something interesting: notes on tiger-type summons. While most of the research focused on their immense combat power, he found an overlooked observation log that deviated from the main line of inquiry. According to these records, the roar of a tiger-type summon had a deterrent power similar to a genjutsu, and its range was extremely wide, capable of being heard for dozens of kilometers and even causing cardiac arrest in common creatures.

In other words, Sasuke realized, the roar has extremely strong penetrating power and can be transmitted over a great distance.

The value of this research material immediately clicked in his mind, connecting with the scientific knowledge from his past life. He remembered from popular science books that the frequency humans can hear is between 20 and 20,000 Hz. Sound waves below 20 Hz are infrasonic; those above 20,000 Hz are ultrasonic. A tiger's roar operates in the infrasound range, between 14-18 Hz.

Infrasonic waves are extremely penetrating and have a great propagation distance. Furthermore, research showed that the sound waves from a tiger's roar could penetrate the human skull and resonate with the brain's alpha waves, causing illusions and nerve paralysis.

"The tiger's roar is actually infrasound!" Sasuke was deeply shocked, his heart pounding with excitement. In the ninja world, enhanced by chakra, the infrasound of a tiger beast's roar would be even more terrifying. That would explain its genjutsu-like deterrent power.

With his previous experience developing the ultrasonic radar, and now with these new research materials, he had a clear path forward. He immersed himself in this new, promising line of research, spending every spare moment in his lab or reading the scrolls while on patrol.

...

"Let's stop for today."

Sasuke stretched, put away his research results for the day, and ran back to the patrol station.

"Captain, you didn't go to the military station to 'have fun' again, did you?" Tekudō teased, sniffing the air around Sasuke. "Smells like disinfectant."

Sasuke tossed him a small bottle of Water Bat No. 6. "If you still want these little darlings, then shut up."

"Alright, I'm shutting up," Tekudō said, caressing the poison bottle as if it were one of his little wives.

Seeing Sasuke return, Ryo and Chōmi immediately started preparing dinner. Sasuke went to fish, while Tekudō practiced his water-walking on a large wooden barrel downstream.

"Infrasonic Radar Technique," Sasuke whispered to himself.

He stood on the river's surface, formed a Tiger seal with both hands, and began to sense. Soon, several Golden Gong Fish appeared in his perception, hiding in a deep pool to his right.

Awesome!

He formed another Tiger seal, and a completely invisible infrasonic wave silently rushed into the deep pool. A few seconds later, a large group of stunned freshwater fish floated to the surface, among which were several of the prized Golden Gong Fish.