Sengoku didn't stop at the mousetrap.
Over the next few days, he scavenged more scrap wood, turning his attention to everyday items like broken tool handles. Drawing on his shinobi training, he carved ergonomic grips designed to perfectly match the natural contours of the human hand. Using a small carving knife, he meticulously etched anti-slip grooves into the wood, mirroring the textured handles of standard-issue kunai to ensure a firm grip even when sweating.
When he finally returned to the bustling civilian market a few days later, he laid out his newly crafted inventory in a high-traffic corner. He sat behind his small spread—the complex mousetrap and several ergonomic tool handles—feeling a quiet, logical confidence.
Reality, however, quickly delivered a crushing blow.
Most pedestrians barely cast his stall a passing glance. The few who did stop picked up his intricately designed mousetrap, turning it over in their hands with deep confusion.
"How exactly are you supposed to use this?" a middle-aged woman finally asked, her brow furrowed as she poked at the interlocking gears.
Sengoku leaned forward, patiently explaining the sensitive lever mechanics and the secondary locking system designed to guarantee a kill.
The woman listened, her frown deepening by the second. "That sounds incredibly tedious," she interrupted, shaking her head. "I just want to put a piece of cheese on a block of wood and hear a snap. My old trap works just fine without a manual." She set the complex device down and walked away.
The ergonomic tool handles fared only slightly better, but still failed to sell. One weathered farmer picked up a carved sickle grip, testing its weight. "The grooves are fancy, I'll give you that," the man grunted. "But out in the fields, sand and mud are just going to get caked deep inside these little lines. It'll be a nightmare to clean." He tossed it back onto the cloth.
Sengoku sat in silence, watching the farmer leave. He had completely misjudged the civilian market.
He had approached the designs with the mindset of a shinobi and a puppeteer—prioritizing lethal efficiency, complex mechanics, and maximum grip. But he had completely ignored the actual needs, habits, and practical aesthetics of ordinary villagers. To them, his designs weren't innovative; they were bizarre, overcomplicated, and highly impractical. Furthermore, it was hard to build consumer trust when the vendor was a seven-year-old child peddling strange contraptions.
He sat there for the entire day. He didn't sell a single item.
By dusk, Sengoku dragged his feet back to his stone house, carrying the heavy burden of his unsold inventory. He dropped the useless tools onto the floor. Not only had he failed to earn a single Ryo, but he had also wasted the last of his usable scrap materials.
The path forward felt utterly blocked. The explosive tags he desperately needed for The Pursuer seemed further out of reach than ever.
Sitting on the edge of his bed, he stared blankly at the sparse remnants of wood and metal scattered in the corner. His chest felt tight with frustration.
Without thinking, Sengoku reached down and picked up his small carving knife. With his other hand, he grabbed a discarded, egg-sized chunk of sandstone left over from an old experiment.
He didn't want to think. He didn't want to engineer, calculate, or strategize. He just needed a physical outlet. He relied on instinct, letting his hands move in a repetitive, focused motion to forcefully grind down the turbulent frustration churning in his mind.
His mind went entirely blank, slipping into a trance. The sharp blade scraped against the rough stone, the quiet shhh-shhh of falling dust filling the silent room.
He didn't know how much time had passed. When the suffocating weight in his chest finally eased and his cold rationality returned, Sengoku blinked, snapping out of his daze.
He looked down, refocusing his attention on his hands.
He froze.
Resting in the center of his palm was not a jagged rock, but a perfectly rendered, flawlessly proportioned miniature kunai.
Sengoku stared at the stone sculpture, then slowly turned his gaze to his own hand holding the knife.
This wasn't just a carving; it was a masterpiece of micro-sculpting. The ring at the pommel was perfectly hollowed, the blade edges were geometrically symmetrical, and the wrapped texture of the handle was detailed down to the individual threads.
The realization hit him like a physical blow.
For months, he had subjected himself to the torturous practice of chakra thread manipulation. He had spent countless hours forcing his chakra into solid iron, painstakingly crafting micro-joints for the Hover Drone, and agonizing over the placement of hair-thin spider silk.
Without realizing it, that grueling, agonizing training had completely rewired his nervous system. His hands now possessed a terrifying, superhuman level of stability and absolute micro-control.
What a master civilian artisan might achieve after decades of painstaking labor, Sengoku could do effortlessly, guided by the muscle memory of a puppeteer.
He had spent all this time trying to use his intellect to invent strange, new tools for a market he didn't understand, constantly hitting a wall. But in this moment of mindless frustration, he had finally uncovered his true, undeniable advantage.
He didn't need to be an inventor. He needed to be an artisan.