Memoirs of an Isekai in Naruto

Log 4: Chakra Expulsion Taijutsu. Fist of a Thousand Hands

This Taijutsu is based on the Hyuga gentle fist taijutsu but focused on using heavy strikes augmented with chakra control and its repulsive effect instead. I base this on a fan fiction story called Naruto: The Outsider's Resolve.

This supplementary Taijutsu chakra control technique focuses on the principles of tree walking and it is necessary that you are at the ABSOLUTE minimum capable of this chakra control skill before you use it. 

When walking up a tree, if you use too much chakra to adhere yourself to a tree, you repel yourself from the surface, leaving an indent of your shoe behind. This indent is due to the incidental chakra flow moving through your shoe strengthening it and making it withstand the impact of the chakra pulling you into the tree. 

As the chakra can no longer adhere to the solid surface of the tree if you don't yet have the skill of water walking and are capable of moving over fluctuating material, the chakra scatters. The force of the motion of the compressed uncontrolled scattering chakra forces you away. The force of motion of these large scattering volumes of compressed chakra is what is trying to be harnessed in this supplementary Taijutsu.

If compressed chakra can hold material to your skin or completely hold up one's physical body it can be extrapolated that the motion of compressed chakra is just as dangerous as the movement of a compressed matter like gas. 

If we do the math the average weight of a male athlete in my world was 164 pounds if we say that that weight is covered by a square foot of space to account for both feet that means just for an athlete to hold themself up it needs a PSI of 1.139. 

It is proven here that a ninja can instantaneously concentrate and sustain a flow of enough chakra to offset a minimum of 1.139 PSI when standing still. The force applied by the foot can range up to 2-3 times when running. This value will likely be far greater as a ninja can easily produce twice as much force given their movement speed. 

For my calculations, my math focuses on the lowest-rank ninja. A fresh graduate likely has a similar physique to an average top athlete. However, I will be treating these values as the baseline mundane man while Jounin is a top athlete. These values will not be fully accurate but make a great baseline for understanding a ninja's body as they have a higher output of force and can also handle higher stresses.

When running up a tree a ninja exerts a minimum of PSI of 3.41. This value is far smaller than the 500-1000 PSI required to break a human bone however we have not taken into account the physical force of any strike added to this force. Mundane humans throw a punch at a psi of 150 PSI. While pro boxers throw about 800 psi with the best of the best throwing 1500 PSI. These athletes' punches are so great they must use hand wraps to secure the bones in their hands and gloves to reduce blunt injury. I will equate these two metrics to average graduates before chunin ranking while Taijutsu specialists like guys throw punches closer to 1500 PSI. 

They Definitely punch harder than these numbers but the ninja's durability is higher than mundane due to Yang energy. This means that for a ninja with a solely mundane level of punching using purely the chakra control enhancement it requires at least a 100-times increase in chakra concentration than what is used in tree climbing. This can be done as seen in the forces applied by a Rasengan examples are when destroying rocks and trees but this skill needs time to charge and concentrate the chakra. In Taijutsu speed is important waiting seconds for this skill to concentrate chakra can be devastating.

Training

Step one: After you get to the bare minimum of chakra control with the tree climbing you need to practice improving the rate of concentration and the total concentration of chakra. Tests can be done where you apply chakra to a hand and lift heavy objects; without a handhold on the object, purely with chakra control to see how much PSI can be concentrated into the hand. 

When one can support about 9310 pounds of weight with just the chakra on the surface of your 26.6 square inch palm. Once this weight is achieved a mundane man with a striking force of 150 PSI can deal bone-breaking strikes of 500 PSI if any part of the hand connects. The chances are this weightage will need to be higher as ninjas are more durable but ninjas' physical punches' are stronger so things likely even out.

Step two: Chakra flow training. After you can break bones you want to protect your own hands. Just like the subconscious use of chakra flow through your shoes you need to wrap your hands and likely use brass knuckles to distribute the weight of your strike more evenly throughout your hand. The downside with the wrapping and knuckles is that hand signs will be far less dexterous. These safety steps are taken in place till one advance in chakra flow far enough that one can enhance a thin cloth glove to give stability in your hands to protect your bones from dislocating. Note these gloves will also act as powerful shields vs both Taijutsu and Kenjutsu.

Step three: This step incorporates Chakra Motion into this Taijutsu. As you are now practiced in Chakra Control and Chakra Flow you have likely progressed your chakra concentration to the point of least lifting a weight of 13,300 pounds as this is the necessary minimum weight for chakra by area for the size of a person's hand to break a bone without the assistance of the physical strike of a fist. Apply motion to this compressed chakra and release these strikes from your fists hitting enemies from a distance. 

This training can be done by placing durable objects at a distance from one's self and punching then compressing the chakra before molding and releasing. The perfect mastery of this step is for the punch not to dissipate before hitting your target and for one to no longer concentrate your chakra into your fist for every strike but to release it anywhere to surprise an opponent when one least expects it. To do this one needs to be able to form their expunged chakra into a construct like the Rasengan.

At this point, you have created weaker Rasengan-like strikes at the rate of a thrown strike. Applying nature change would be advised but it is highly unlikely that this is possible. The speed of compression shaping and motion applied to the movement of chakra leaves little to no time for effective nature change. 

Step four: Step four for mastery beyond improving the previous three attributes constantly is shaping. There are two shaping improvements that can be made size and quantity. You can improve the size of your strike to produce smaller needle-like strikes or larger blows. The second is needed to concentrate multiple points at a time across the body to release multiple strikes simultaneously. If the enemy is too powerful these multiple strikes give you time to build up larger finishing strikes. This final step is where this Taijutsu style gets its name.

Footnotes: my next log will be focused on a water lighting release meant to enhance fire Jutsu if you lack wind nature but want to be useful to the primary fire nature of the hidden leaf village