Throne Of The Uchiha

Sealing Technique

"With your current strength, you are now eligible to access some of the Uchiha clan's deeper secrets," said Uchiha Tenjo as he pulled a tightly bound scroll from a hidden shelf. He handed it to Fugaku with a solemn look. "This is one of our clan's preserved scrolls on fūinjutsu — sealing techniques."

"Fūinjutsu is deceptively simple to learn but extremely difficult to master. Only a rare few in the shinobi world ever reach true proficiency. Most of them were taught from a young age by masters of the art," he added.

Fugaku nodded. He had read accounts of shinobi like the Uzumaki clan, whose mastery of sealing techniques became legendary before their downfall. In the current era, only a handful could even replicate basic techniques from their arsenal.

Tenjo handed him a small, black-lacquered box. "This is the key to the secret chamber," he said. It was shaped like a pentagon, engraved with intricate Uchiha clan markings and ancient elemental scripts.

"From now on, you may spend a few days each month exploring our ancestral jutsu and fūinjutsu records," Tenjo said. "But don't lose yourself in it. Strength is still paramount. No matter how many jutsu you know, without power to back them up, it means nothing."

He continued, "Many talented clan members have drowned themselves in the pursuit of knowledge, but failed to awaken the Mangekyō Sharingan or step into the upper ranks of the shinobi world."

"I'll remember your words, Father," Fugaku said respectfully.

After exiting the hidden chamber, Tenjo was called away by duties involving the guard corps. Left alone, Fugaku looked down at the scroll in his hand and slowly unrolled it.

> Fūinjutsu is a complex art involving the manipulation of chakra patterns, symbols, and ritual formulas to bind, seal, or suppress objects—both physical and metaphysical. These may include living beings, chakra signatures, memories, or even time-delayed techniques.

Though not famed for sealing, the Uchiha clan had accumulated a wealth of sealing knowledge over generations—spoils and copied techniques gathered from the Warring States Era. They had long respected the discipline, even if it was not their main strength.

The first part of the scroll detailed sealing formulas—kanji-based glyphs that corresponded to elemental natures, time delay triggers, spiritual binding, and chakra containment. It noted that high-level sealing could bypass hand seals altogether, using direct chakra manipulation to etch formulas internally—like Orochimaru's Gogyō Fūin (Five Elements Seal), which disrupted the Shiki Fūin placed by the Fourth Hokage on Naruto's stomach.

Fugaku began with the basics—memorizing and hand-inscribing the formulas on wood planks and parchment. For two weeks straight, he dedicated his evenings to studying sealing formations. He was disciplined and methodical, taking careful notes and testing formula resonance with his chakra.

Eventually, it was time to test.

Behind the Uchiha compound lay a forested slope — quiet, lush, and covered in green throughout the year, thanks to the Fire Country's temperate climate. Old training targets dotted the area, many cracked and weatherworn.

Fugaku crouched beside a small ant hill. He used a fine ink brush to draw a simple boundary seal around the nest. It took him ten minutes to carefully trace each symbol and connect the chakra flow lines.

He activated the seal with a basic kai hand sign and slapped the ground. Chakra flowed through the inked lines. The moment the pattern lit up, a barrier shimmered into existence, encasing the hill.

For a moment, it held. Ants trying to leave bounced off an invisible wall. Some began to gnaw on the glyphs. The barrier flickered, then broke.

"A raw sealing array without a stable medium can't last long," Fugaku murmured. Still, it was a successful test of formula flow and chakra control.

The entire afternoon was spent experimenting with such patterns—containment, delay-release, suppression arrays—on smaller animals. By evening, he caught a mouse, brought it home, and placed it inside a reinforced glass box.

He carved sealing symbols into the box's base, sides, and lid, then placed the mouse inside and activated the array. A faint humming surrounded the glass. The mouse ran frantically, but the box remained sealed. Even though the lid wasn't locked, the chakra-linked barrier made it impossible to lift.

This time, the experiment was a complete success. The seal was stable, and the creature's attempts to escape only confirmed its strength.

For the next half month, Fugaku refined his work—progressing from mice to squirrels, to rabbits. He experimented with chakra-triggered release seals, motion-sensitive traps, and even basic suppression fields—used in wartime to neutralize enemy jutsu storage scrolls.

---

A full month had passed since his return from the Amegakure mission. Fugaku's understanding of sealing was still basic compared to a master like Jiraiya, but his control and theory were solid. He could now inscribe and activate functional seals reliably.

Back at the forested slope behind the compound, he planned to test on a larger animal today.

"You've been hard to find lately," said a familiar voice behind him.

Fugaku turned. "Uchiha Jin," he greeted with a faint smile.

"I heard from the clan leader you've been studying fūinjutsu. That's rare for someone aiming to be a frontline Jonin. Advanced stuff, sure—but shouldn't you focus more on combat training?"

Fugaku gave a calm nod. "Don't worry. My training hasn't slacked. In fact, I've made solid progress lately."

Jin raised an eyebrow, amused. "That so? It's been a month since we returned from the Rain Country. Let's see what that progress looks like. Spar with me?"

Fugaku didn't hesitate. "Sure."

The two moved to a clearing. This wasn't the same Fugaku who'd lost to Jin a few months ago before his Jonin promotion. Now, Fugaku had grown—in skill, in control, and in presence.

Both activated their Sharingan—three tomoe spinning in perfect symmetry. But Fugaku's Sharingan held a deeper gleam, enhanced by repeated chakra battles and the emotional growth he'd undergone during recent missions.

Jin felt it too. This wasn't just another match. He'd have to go all out to avoid losing to someone younger—especially someone he had once defeated.

As the two squared off, their chakra flared against one another.

The seal master was now a true warrior—on the path not just of knowledge, but of strength.

---

Notes on Manga Accuracy:

The Uchiha are not known for fūinjutsu, but it's plausible they would collect and study it from defeated clans during the Warring States Era.

Orochimaru's Five Elements Seal and the Eight Trigrams Sealing Style (used by Minato) are canon examples of how fūinjutsu affects chakra flow.

Chakra-based sealing with formula carving (used by the Uzumaki, Orochimaru, and Jiraiya) is accurate to the lore.

Glass as a sealing medium is used in Naruto for storage (e.g., ink bottles, animal containment), though often chakra-infused materials like paper and stone are favored.

Sharingan power scaling through emotional growth and exposure to battle is consistent with canon.