Shinra stared at the damaged tree.
The hole beneath his fist was deeper than he had expected. The first impact had already broken through the trunk and damaged the wood underneath, but the second wave of chakra had clearly done something different. Instead of simply adding more force to the original strike, it had travelled into the damaged section and caused the weakened wood to collapse from within.
He touched the edge of the hole with his fingers.
The wood was splintered and uneven.
'The second impact isn't stronger than the first.'
The destruction made it look more impressive, but most of the damage had been caused because the second impact struck a structure that had already been weakened.
Shinra looked at his fist.
'If I used this against a person, the result would depend heavily on where the first strike landed. Its unpredictability is a major advantage, but it's still not as powerful or unpredictable as Frog Kumite.'
That wasn't necessarily a problem.
A technique didn't need to be overwhelmingly powerful by itself to be useful. It only needed to create an advantage that another technique couldn't.
The more important question was whether he could reproduce it at will mid-battle.
Shinra stepped away from the tree and flexed his fingers.
The first attempt had happened because he had accidentally noticed the difference between his physical movement and his chakra. He had then deliberately kept some chakra compressed in his arm and released it after the initial impact.
That part seemed simple.
Actually controlling it was another matter.
He gathered chakra into his right arm.
This time, he didn't move.
He focused entirely on the chakra.
It flowed through his arm smoothly, following the path he established. Shinra gradually increased the amount until he could feel the pressure building inside his muscles.
Then he released it.
Nothing happened.
There was no target for the chakra to interact with, and without a physical movement accompanying it, the sensation was completely different from what he had experienced earlier.
Shinra frowned.
'So even if I release the chakra, it won't cause a major effect unless it's in contact with an object. That's a shame. I was hoping I would be able to release air blasts from my fists.'
Since he needed a fixed target, this large tree would serve well enough.
Shinra returned to his previous position and raised his fist.
He gathered chakra.
Moved forward.
His fist struck the trunk.
THUD!
He kept a portion of the chakra compressed.
Then released it.
BOOM!
The massive tree shook.
Shinra immediately looked at the damaged section.
The second impact had occurred, but it was weaker than before.
There was a small crack around the original hole, but nothing more.
'It isn't like the last time. Does the problem lie in the release period?'
He tried again.
This time, he increased the amount of chakra he held back.
THUD!
BOOM!
The result was better.
The second impact caused another section of the tree to break apart, but Shinra could tell that something was still wrong.
The delay had been longer.
He could feel it.
The first time, the second impact had followed almost immediately. This time, there had been a slightly longer gap between the physical strike and the chakra release.
It wasn't much.
Perhaps a fraction of a second.
But Shinra's sensory ability allowed him to notice it.
'So the amount of chakra affects how long I can hold it?'
He wasn't certain.
He needed more tests.
For the next several minutes, Shinra repeated the same process while changing only one variable at a time. Sometimes he reduced the amount of chakra he held back. Other times he increased it. He experimented with releasing it immediately after contact and then waiting longer before allowing it to escape.
The results were inconsistent.
A small amount of chakra produced a weak second impact.
Too much made the chakra difficult to contain.
Waiting too long created another problem.
The chakra didn't remain perfectly still inside his arm.
It continued moving.
Shinra frowned.
'This time, the problem is that I'm unable to control the compressed chakra properly. That weakens the second impact and makes the delay difficult to control.'
Shinra discovered that he could compress it, but compression wasn't the same as freezing it in place. The longer he held the chakra, the more pressure accumulated, and eventually maintaining control became increasingly difficult.
Shinra immediately understood the problem.
'The longer the delay, the harder it becomes to control where the chakra goes. It's similar to what happens when a blood vessel is blocked—the pressure of the flow increases.'
That made sense.
Chakra wasn't a physical object he could simply store inside his fist and release whenever he wanted. It was energy flowing through his chakra network.
The technique worked because he was controlling that flow with enough precision to create a small separation between the initial hit and the second impact.
If he pushed that separation too far, he would lose the advantage. But currently, he was unable to control that separation reliably, leading to another headache.
Shinra sat down beside the tree.
The four hundred kilograms were still weighing heavily on his body. His breathing had become deeper, and sweat covered his forehead despite the relatively cool air.
He closed his eyes.
'Maybe I'm approaching this from the wrong direction.'
He had spent most of his training learning how to consistently manage the timing and strength behind the punch.
The Rasengan was a perfect example.
He had to maintain several different forms of chakra manipulation simultaneously. Rotation, compression, shape transformation. Any imbalance could destabilize the technique.
But this was different.
He wasn't trying to synchronize his chakra with his body anymore.
He was trying to control the difference between them.
Shinra opened his eyes.
'Maybe instead of compressing the chakra and trying to release it at the right time, I should slow down the chakra flowing toward my fist and let it reach the point of impact immediately after the first strike lands. It wouldn't be as strong, but it should allow me to control the timing.'
That realization simplified things.
He didn't need to hold his chakra for half a second.
He didn't need some dramatic gap between the two impacts.
A tiny delay was enough.
The human body already reacted to impacts in ways that weren't immediately obvious. If the second wave of chakra arrived at the right moment, even a small separation could create an opening in unsuspecting opponents.
Shinra stood.
He deactivated the seals and dropped the weights.
The sudden loss of weight made his body feel almost unnaturally light.
He moved his arms and shoulders before activating them again.
This time, Shinra didn't immediately begin punching the tree.
He moved his arm slowly and started directing chakra toward his fist, deliberately slowing its flow.
He raised his fist.
He began moving before the chakra could fully reach his hand.
The punch accelerated slower than normal.
His fist travelled toward the tree.
THUD!
He felt the impact.
Immediately afterward, he allowed the delayed wave of chakra to continue flowing into his fist.
BOOM!
The second impact was small.
But Shinra smiled.
Not because of the damage.
Because this time, he had managed to control the delay.
The chakra had remained under his control throughout the entire movement.
'The reason I was unable to control the delay at first was because I was trying to combine two incompatible techniques. In the case of Tsunade and Sakura, their technique involves gathering chakra and heavily concentrating it before releasing it at the exact right millisecond, creating a powerful force.'
He looked at the tree.
'I hate to admit it, but my chakra control isn't at the level where I can pull this off.'
Shinra sighed.
'In this case, instead of trying to release the chakra at the exact millisecond, I simply need to direct my chakra flow so that it reaches my fist immediately after the first impact has landed.'
He repeated the motion.
THUD!
BOOM!
The timing was once again as he intended.
Shinra adjusted the speed of his chakra flow.
Again.
THUD!
BOOM!
He continued practicing.
Shinra spent the next hour fine-tuning the technique and getting used to it.
'Again.'
THUD!
BOOM!
Again.
THUD!
BOOM!
After several more attempts, Shinra finally stepped away from the tree.
The trunk was covered in holes and cracks, but he was no longer interested in testing the technique against something that couldn't fight back.
He had learned enough.
The real test would be against himself.
Shinra formed a hand seal.
A shadow clone appeared beside him.
The clone glanced at the tree full of holes before looking back at Shinra.
"Want to test it?"
"Yes."
The clone nodded and moved several meters away.
Shinra lowered his stance.
The spar began.
The two exchanged several blows, neither gaining a clear advantage. The clone was useful precisely because it knew Shinra's habits and understood his fighting style.
Shinra eventually decided to create an opening.
He stepped forward and threw a punch.
The clone raised its arm to block.
THUD!
His fist struck the forearm.
The clone immediately prepared to counter.
BOOM!
The delayed chakra struck a moment later.
The clone's arm was knocked aside, creating the opening Shinra needed. He stepped forward and landed another strike before the clone could recover.
Shinra's eyes narrowed.
'It works.'
The clone quickly adapted.
During the next exchange, it began moving away from his punches instead of blocking them directly. When Shinra used the delayed impact, the clone anticipated the second strike and reduced its effect by moving with the first impact instead of resisting it.
Shinra didn't mind.
That was exactly why he was testing it.
He continued sparring, mixing normal punches with delayed ones rather than relying on the technique every time. After several minutes, he had a much better understanding of its limitations.
The delay couldn't be too long.
The amount of chakra couldn't be excessive.
And if the opponent knew about the technique, they could easily adapt to it.
Still, Shinra was satisfied.
The technique didn't need to be impossible to defend against.
It only needed to catch someone off guard.
The clone disappeared in a cloud of smoke, returning all of its experience to Shinra.
He stood quietly for a moment.
'It's usable. In terms of effect, this technique could barely be considered C-rank in its current state. Its biggest downside is that it still requires a high level of chakra control. If I ever manage to successfully incorporate chakra compression into it, then it might become a trump card.'
Shinra sighed.
That was enough.
He turned toward the equipment he had left nearby.
His gaze settled on his sword.
Shinra picked it up and examined the blade.
The new technique had been useful, but he still had another problem to solve.
His sword technique.
The technique had given him a tremendous burst of speed, but it was still incomplete. Once he activated it and committed to the thrust, his body had to follow the sword's trajectory.
Sasori had already exploited that weakness.
Shinra hadn't forgotten.
He lowered the sword before raising it again.
Lightning chakra began flowing through the blade.