Sword Leap: Flame.
More precisely, Sword Leap: Flame, Revised.
Among Uchiha Shisui's three sword forms, Sword Leap: Flame was the foundation. A direct cut, fire chakra drawn along the blade to form a burning edge. No tricks. No wasted motion.
The weakness was obvious.
Shisui's original form carried a trace of wind chakra. Not enough to dominate the technique, but enough to sharpen it. Fire rose faster. The blade arrived sooner.
Sasuke didn't have that option.
No wind affinity.
Developing a new chakra nature took years of careful conditioning. Even jōnin treated it as a long-term commitment. Sasuke had neither the time nor the patience for that detour.
Lightning wasn't viable either. Not yet. He hadn't even begun structured Lightning Release training.
So he changed the problem.
If speed couldn't be borrowed, then force would replace it.
Sasuke stood in the Uchiha training ground, blade half-drawn. Fire chakra flowed into the steel, not flooding it, but compressed and layered. Fine streams of chakra moved along the blade's surface, grinding against one another, accelerating.
Heat climbed.
Fire wasn't fast.
But fire exploded.
The moment he moved, the draw was absolute. The curvature of the scabbard guided the blade, friction converting stored heat into a single burst. The strike wasn't wide. It didn't need to be.
The outcrop ahead split cleanly.
Stone parted. Heat lingered.
Sasuke exhaled once and slid the sword back into its sheath.
"This works," he said quietly.
It wasn't Shisui's Sword Leap: Flame anymore. But in raw output, it didn't fall behind. In burst power, it surpassed it.
He turned.
A cat sat on the roofline, tail flicking once.
Homura.
Five small scrolls were secured to its back.
Sasuke allowed himself a faint smile and walked over.
That night, after meditation, he unrolled the first scroll.
Lightning Release.
No advanced techniques. No forbidden methods. Just theory, control exercises, and low-ranked jutsu. Diagrams. Chakra flow patterns. Repetition drills.
As expected.
Sasuke read anyway. Slowly. Carefully. Nothing was skipped.
An hour later, he set the scroll aside.
There was no mention of cellular stimulation.
Lightning Release was inherently dangerous. Techniques that accelerated the body itself existed, but they were rare and tightly guarded. Poor control didn't just injure the user. It killed them.
Two names surfaced unbidden.
Chidori.
And the Raikage's lightning armor.
Both demanded preparation far beyond raw talent.
Sasuke closed the scroll.
Starting now mattered.
Foundations decided everything that came later.
He extinguished the lamp and returned to stillness, the faint echo of thunder lingering in his thoughts.