The Book of Seals was a forbidden repository, sealed by Hashirama Senju, the First Hokage. It held Konoha's most guarded techniques—secret ninjutsu and advanced jutsu that only a handful of shinobi could even glimpse.
Not just anyone could open it. Only those who had made great contributions to Konoha could be granted access.
If it weren't for Utatane Koharu's passionate insistence—backed quietly by his father, Kagami—Hayashi might never have been given this chance, even with all his accomplishments.
With anticipation burning in his chest, Uchiha Hayashi channeled chakra into the scroll.
This scroll wasn't the Book of Seals itself, but rather a list of jutsu he could "trade" for, drawn from the forbidden book. A curious black-inked pen hovered beside the list, its markings strange and precise.
He scanned the first entry: Multiple Shadow Clone Technique, originally developed in the canonical universe by the Second Hokage.
Hayashi raised an eyebrow. Why would such a "forbidden" jutsu appear? Its hand seals are identical to the standard Shadow Clone Technique — any shinobi who already knows the basic clone jutsu can learn it. It's common. The only real limit is chakra.
He skipped it.
Scrolling further, he found no Wood Release techniques. Nor did he find the infamous Reanimation Jutsu — the kind of forbidden technique that could rival even the strongest jutsu of the other villages.
But then his eyes locked on a name that made his pulse quicken: Summoning Technique – Rashōmon.
This was a powerful defensive jutsu, used in canon to summon a huge gate-like structure. According to lore, it blocked devastating attacks—even tailed beast bombs.
Hayashi felt his heart race. His other defenses weren't nearly as reliable as this.
Yet, he kept scrolling.
Next came Flying Thunder God Technique.
This space-time ninjutsu, originally created by Tobirama Senju and later perfected by Minato Namikaze, allowed instantaneous teleportation to previously marked locations.
His mind wandered: Minato had mastered it. If Hayashi learned it, he and Minato could coordinate even more effectively. But was it wise to give it to Minato now? He had only just begun exploring sealing techniques. The Flying Raijin required a strong grasp of spatial theory—a foundation Hayashi wasn't fully certain Minato had yet.
He hesitated. Could Minato handle that? Maybe not yet.
He continued scanning.
Another jutsu caught his eye: Spirit Transformation Technique. But the more he thought about it, the less appealing it became — once used, his physical form would be left vulnerable. He didn't like that risk.
Most of the rest of the scroll listed fairly ordinary A-rank jutsu, nothing extraordinary. The Book of Seals, as it turned out, was selective.
It wasn't because Hokage Hiruzen was hiding every powerful technique. Rather, some techniques simply weren't appropriate for someone of Hayashi's age. Forbidden jutsu like the Reaper Death Seal were too dangerous — even the Hokage wouldn't let him near that.
Still, the scroll only gave names. No detailed explanations. If he didn't already know some of them, he risked choosing blindly.
At the bottom of the scroll, one last name glowed in his mind: Mutual Instantaneous Explosion Tag.
He paused.
This explosive jutsu, said to be developed by the Second Hokage, was terrifying in its scale. The idea was simple: place a single explosive tag on an enemy, then detonate it. But when triggered, it could repeatedly summon more explosive tags, setting off an endless chain of explosions.
It sounded nearly as destructive as Konan's rain of paper tags. But unlike an S-rank jutsu, this technique was surprisingly "simple" — only A-rank in difficulty to learn.
There was a risk, though. The caster could easily be caught in their own chain reaction.
But the potential… the power…
Hayashi's hand froze over the ink-pen. He stared for nearly a minute, thinking. Finally, with a firm grip, he marked the box next to Mutual Instantaneous Explosion Tag.
Immediately, the scroll in his hand vanished in a wisp of white smoke. A new scroll appeared—sealed, but alive with energy.
He opened it. The scroll described both the benefits and risks of the technique. It showed how to summon tools, how to train for continuous tag summoning, and even how to craft specialized explosive tags.
Hayashi read quickly, memorizing every line. Then he carefully rolled up the scroll and tucked it into his pouch.
This kind of training couldn't happen in his room. Too dangerous. He could destroy his belongings or worse, hurt someone.
He needed an open space.
Where better than Hokage Rock?
He tucked the scroll away.