Devils_hand
The Body Replacement Technique is not a space technique, but it is a degraded type of summoning technique. In order to summon the wood log, the location of the clinch and the smoke is not a defect. It is to cover your escape routes. It cannot be a space technique, because the space techniques cannot be performed without space convergence.
Body Replacement Technique This ninjutsu lets a ninja quickly replace their body with a nearby object such as a plant or animal. It is used to evade an enemy’s attacks, allowing them to escape a lethal blow and gain an advantageous position over their enemy. It surpasses simple speed or reflexes, and the use of a replacement object makes it harder to detect until it is too late. Despite how it appears, this replacement is not instantaneous. Like the Body Flicker Technique, it is an example of high speed movement that causes the caster (and the target) to move faster than the eye can see. This is what makes it difficult to use at the higher levels of shinobi combat as a skilled enough ninja are able to discern its use, either intercepting it or tracking the caster. The caster’s chakra latches onto the object they want to replace themselves with, binding the two of them together and slipping them past one another until they reach the other’s original position. The curious nature of this movement means that a ninja can use it even while being restrained or are in mid-air. This replacement will often create an optical illusion, an after-image infused with chakra, allowing it to change in reaction to the attack and fool the enemy into believing that they had succeeded. The most common object that ninjas use to replace themselves with are wooden logs. Primarily because they are most convenient objects to swap with, the ideal size and easy to get a hold of. It’s not even uncommon to have them set up on a battlefield beforehand for future body replacements. The targeted object needs to be within the immediate vicinity for it to be in range of the ninjutsu. And if it is too small or too large in comparison to the caster, then the ninjutsu cannot effectively grasp it. It is not impossible for the ninjutsu to be cast on another person but it is one of the more difficult ways to use it. Without a certain difference of power and skill between the caster and target – such as a genin and a jounin or a civilian and a genin – the chakra of the other individual can interfere with the body switch to prevent it from taking hold.
Mano com seis olhos ele pode compreender o espaço, para que porra ele tá fazendo essas coisas inúteis. Ele tá usando um jutsu de conexão, mas tá dizendo que é espacial ?. Ele fala que uma qualquer pessoa pode usar esse jutsu ?. Se for o que ele tá dizendo que usa o 'espaço', como a porra de uma criança pode brinca com espaço?.
You know that body flicker had already been perfected by Shisui Uchiha she even had a nickname because of this technique I think it was Shisui of Body Flicker something like that, so no your MC is not the first to see the potential of this technique it's also likely that others cannot use this technique because of the speed it moves the mind cannot follow which is not a problem for those who have Sharingan as it alters the perception of time.
Guys chill, the author is being logical (in his own way), it doesn’t have to check out 100% to you. Substitution jutsu might not be a pure spatial movement technique but… hear me out. We all exist within space right? Dislacement from one point to another (summoning or what not), without conventional methods (walking, running, swimming, flying…) IS SPACE REALATED. And mind you, summoning doesn’t just occur because of SUMMONING and nothing else, space laws are involved somehow. Correct me if I’m wrong. (Sorry for the double comment)