Testing the Ninja Tool

Pushing open the creaking wooden door, Uchiha Rin returned to his drafty plank house in the slums. The night wind slipping through the cracks in the walls carried autumn's chill, making the oil lamp hanging from the rafters sway gently as its dim yellow light cast fragmented shadows across the room.

After nightfall, the cold restlessness deep within his meridians began to stir again—an old affliction he had suffered from for as long as he could remember. Whenever night fell or his emotions fluctuated, the dark chakra settled in his lower abdomen would begin to move, battering his meridians like a trapped beast. He had to focus and hold his breath to barely suppress it.

He bolted the door behind him, sat down before the mottled wooden table, adjusted his state, and pushed open the blade guard with his thumb before slowly drawing the short sword.

The pale blue blade lay steeped in the warm yellow lamplight, gleaming with a cool, lustrous sheen. The fine patterns that had been hard to make out during the day now showed in perfect detail—they were not markings carved by an outside hand, but more like veins grown from the metal itself. Like blood vessels, they wound out from the hilt, extending all the way to the tip and spreading along the curve of the blade's spine, seamless and natural.

He calmed his mind, suppressed the faintly swelling chill within him, and sent a thread of chakra from his palm into the hilt. At first, the blade showed no reaction. But the instant his chakra touched those veins, the familiar warmth in his palm suddenly intensified.

His chakra seemed gently drawn by some force, flowing steadily along the patterns toward the blade's core. At the same time, the trapped beast rampaging through his meridians seemed cowed by something. Its surging momentum abruptly stalled, and the restless chill inexplicably weakened by several degrees.

Uchiha Rin's heart tightened. Instinctively, he wanted to pull back, but he found that this suction was not violent. It carried none of the brute force of plunder; it was more like a gentle acceptance. He stopped moving and let his chakra flow in slowly. The blade's patterns glimmered pale blue as the chakra entered, brightening and dimming once like a breath before returning to stillness. The troubling chill within him also seemed soothed by that warmth, quietly sinking back into the depths of his body.

He loosened his grip, withdrew his chakra, and let out a slight breath. That had consumed roughly one-tenth of his chakra—not a large amount, but clear enough. He gripped the hilt again, but the suction had vanished completely. The blade rested quietly in his palm, indistinguishable from an ordinary short sword.

Uchiha Rin laid the sword across his knees and lightly ran his fingertips over the patterns along its spine, his mind racing.

He had seen records of ninja tools capable of storing chakra in the Ninja Academy's textbooks. Master ninja tool craftsmen could embed specialized sealing formulas during forging, allowing weapons to hold their user's chakra and release it in a burst at critical moments. Such craftsmanship was exceedingly difficult to master, and the finished products were mostly custom equipment for jonin. Ordinary ninja would struggle even to see one.

And he had picked up a sword like this for five hundred ryo from an old box in the corner of a ninja tool shop.

He leaned closer, carefully studying the direction of those veins in the lamplight. He had learned the structure of basic sealing formulas, but the arrangement, turns, and connections of these patterns were utterly unlike the textbook models. They formed a system of their own, so unfamiliar that he could not make sense of them at all.

Suppressing his surprise, he tried infusing chakra again. This time, he deliberately slowed the pace, precisely controlling the output as he carefully sensed the blade's changes. The pale blue glow lit up along the patterns in sequence, flowing across the entire blade like water, while the pulse in his palm became distinct and powerful.

About ten minutes later, the blade gave off a subtle sense of saturation—no matter how much chakra he urged into it, those veins would not absorb another trace. Like a container filled with water, it had come to a steady stop at its threshold. He estimated that the chakra stored in the sword was roughly equal to the total amount he could naturally recover in a day.

The room was cramped, and its beams and pillars were all load-bearing. Swinging the sword recklessly might destroy the already flimsy house, and too much noise could easily draw attention. Uchiha Rin rose, sheathed his sword, gently pushed open the back door, and walked into the clearing behind the house.

The night was thick as unbroken ink. Clouds obscured most of the moonlight, leaving only scattered traces of light across the wild grass. A half-rotted old wooden stake was driven crookedly into one corner of the clearing. Its bark was dry, cracked, and rough—a piece of discarded firewood from one of the nearby homes, perfect for testing the blade.

He stopped before the stake, flicked his wrist, and lightly swept the chakra-laden blade toward its side.

There was no expected chopping sound. The blade brushed the wood as though it had passed through air.

Uchiha Rin froze for a moment, then reached out and touched the stake's surface—the cracked grain remained perfectly intact, without even a faint scratch.

He frowned. With a thought, he withdrew the floating chakra layer covering the blade's surface, lowered his wrist, and swung again at the stake.

A faint hiss sounded. The blade sliced into the stake without resistance, cutting nearly an inch deep. He sheathed the sword and looked down at the cut—the cross-section was smooth and even, as if it had been carefully polished. Not a single wood splinter had lifted.

He stood in the night wind with one hand on the hilt as the wild grass rustled around him. A clear conclusion gradually formed in his mind:

When filled with chakra, the blade was covered in an invisible chakra layer, but it lost its physical sharpness and seemed geared more toward effects on the chakra level. When empty, the sword's own sharpness far surpassed that of any standard-issue ninja tool. The stored chakra was clearly not meant simply to strengthen its cutting power; there had to be another method of releasing it.

And the sword's warming, calming effect might be even more important to him than its sharpness.

He returned to the house, sheathed the sword, placed it beside his pillow, and blew out the oil lamp in one breath.

Darkness instantly swallowed the little house. Outside the walls, night insects chirped one after another, and the occasional bark of a dog drifted from the distant alley, mingling with the wind striking the plank walls. Uchiha Rin lay on the hard straw mat, the warmth of the hilt still lingering on his fingertips.

He remembered the shopkeeper's casual words that afternoon: "Just a bunch of junk nobody wants."

In the darkness, the corner of his mouth curled into a faint, nearly imperceptible smile.

That shopkeeper would probably never know what kind of treasure he had sold for five hundred ryo.