When I turned eight, the results of the past years of training finally began to compound.
Until then my improvements had been steady but gradual. Now my body started responding faster to training. Exercises that once pushed me close to exhaustion began to feel routine. My muscles adapted quicker, and recovery between sessions improved noticeably.
Running through the forest no longer required careful pacing. My footing felt natural even on uneven ground. Climbing trees became effortless. Carrying water from the river, which once strained my arms, barely felt like work anymore.
The difference wasn't dramatic to look at, but I could feel it clearly.
My strength had increased.
My speed had improved.
And my endurance had grown far beyond what it had been even a year ago.
But instead of simply pushing my body harder, I decided to experiment with something new.
Breathing.
The idea came from a memory of something I had watched in my previous life—an anime called Demon Slayer.
In that story, warriors used specific breathing styles to strengthen their bodies and maintain stamina during battle. Obviously the techniques in that series were exaggerated, but the underlying concept made sense.
Breathing controlled oxygen intake.
Oxygen fueled muscles.
And muscles determined endurance and power.
If breathing could be optimized during movement, then physical performance might improve as well.
So I decided to test the idea.
Not by copying what I remembered from that story exactly.
But by deliberately experimenting with breathing patterns during training.
My running sessions became the first testing ground.
Instead of breathing naturally, I began controlling the rhythm.
Two steps inhale, two steps exhale.
Three steps inhale, three steps exhale.
Short explosive breaths during sprints.
Long controlled breathing during endurance runs.
Most of those patterns didn't work.
Some made my stamina worse.
Others disrupted my running rhythm completely.
But gradually certain patterns began producing better results.
Deep inhalation through the nose followed by a longer controlled exhale stabilized my stamina during long runs.
Short, sharp breaths synchronized with sudden movements improved explosive actions like jumping or sprinting.
Encouraged by those results, I pushed the experiments further.
The river became the perfect place to test breathing under pressure.
Moving against the current required constant tension in the legs and core. If my breathing pattern was inefficient, exhaustion arrived quickly.
But if the breathing rhythm worked, I could maintain movement much longer.
So I experimented there as well.
Walking upstream while maintaining controlled breathing.
Holding my breath briefly while stabilizing against the current.
Synchronizing short bursts of breath with explosive movements in the water.
Over time a stable rhythm formed.
It wasn't complicated.
Controlled inhalation through the nose.
A slightly longer exhale.
And breathing synchronized with movement.
The result was subtle but clear.
My stamina improved.
I could maintain training intensity longer than before.
And occasionally, when I used short explosive breaths during sudden movements, my body produced brief spikes of power.
Not something dramatic.
But noticeable enough to matter.
At the same time my body continued improving physically.
Years of training were finally compounding.
My strength increased steadily. Pull-ups and push-ups became easier, and I could carry heavier loads without fatigue.
My speed improved as well. Running through forest paths felt smoother and faster than before.
But the most noticeable change was endurance.
Between river training and breathing control, my stamina had grown far beyond what most children my age possessed.
During sparring sessions I rarely became tired before the older teenagers did.
One afternoon after a long sparring match, Jiro stared at me suspiciously.
(Why aren't you breathing hard?)
I shrugged.
(Training.)
He shook his head.
(You're strange.)
Maybe.
But the results were obvious.
Around the middle of that year I refined another idea.
Tracking progress.
Simply feeling stronger wasn't precise enough. I wanted a clearer way to understand my physical limits.
So I created a simple internal scale.
I called it the pressure stages.
Instead of numbers, the system tracked how my body reacted to increasing strain.
The first stage was Stable Pressure.
In this state the body performed normally. Breathing remained calm and movements felt efficient. Most training happened here.
The second stage was Heavy Pressure.
Muscles began to strain and breathing became deeper. Movements required more effort but remained controlled.
The third stage was Maximum Pressure.
This was the limit. Muscles trembled, breathing became intense, and continuing beyond this point risked injury.
The system worked surprisingly well.
At the beginning of the year certain exercises pushed me into the second stage quickly.
By the end of the year those same exercises barely moved me out of the first.
Which meant my capacity had grown.
The improvements became most obvious during sparring.
Teenagers around fourteen or fifteen often practiced near the clearing. Occasionally they allowed younger children to join.
By the time I was eight, I could hold my own against them.
Not through strength.
But through mechanics.
Years of balance training allowed me to stay stable even when pushed.
Understanding leverage helped me redirect their momentum.
And controlled breathing prevented fatigue from building up during long exchanges.
One sparring match lasted nearly ten minutes before the older boy finally stepped back laughing.
(You're annoying to fight.)
Jiro burst out laughing from the side.
I simply smiled.
That reaction meant the training was working.
Evenings remained dedicated to books.
Dad continued bringing texts from trade towns whenever possible. Some were simple travel records, others were guides written by healers and merchants.
The medical books remained the most useful.
They explained how muscles worked together during movement and how injuries occurred when joints lost alignment.
That knowledge allowed me to refine my training further.
I adjusted exercises to strengthen weaker muscle groups.
Improved posture during movements.
And experimented with recovery techniques using herbs Mom prepared.
Between training and study, my understanding of the body continued improving.
By the time my eighth year ended, several things had become clear.
My physical abilities had grown significantly.
Strength, speed, and endurance had all improved.
The breathing technique—an experiment inspired by Demon Slayer—had successfully increased my stamina and allowed occasional bursts of explosive movement.
The pressure stage system allowed me to track my limits clearly.
And my combat mechanics allowed me to spar with fighters nearly twice my age.
Years of preparation had finally built a solid foundation.
Strength.
Balance.
Breath.
Control.
Everything was beginning to come together.