While the ancient style is classified to be impenetrable, Shikon’s Space Time Ninjutsu Barrier is not blockading any trespasser to go in and out. His pocket dimension focuses to alter the sense of time and disrupt the chakra flow. This allows him to make his trespasser slower as he changes the speed of time, while it does not affect him. On the other hand, the farther the trespasser is from him, the closer they would be to the normal speed of Earth. The closer they are to Shikon, the slower the time will go for them. Disrupting the chakra flow allows Shikon to disable the trespasser’s ability to mold chakra and perform jutsu of any kind.