Chapter 173:
Did Orochimaru just use a genjutsu?
No, not exactly.
It was impossible to cast an illusion from that distance. Genjutsu isn't some invincible technique that ignores distance or movement.
The ability Orochimaru used was indeed a unique Mangekyo technique—"Space Confinement," a different ability from any in his memory.
Of course, it sounds powerful, but there are quite a few limitations.
The range is limited to a hundred meters, with an area of effect only five meters in radius, and the confinement lasts for just five seconds. The strength of the confinement also varies depending on the charge-up time.
Using it immediately upon activation merely slows down the target. To completely immobilize someone, Orochimaru found he needed about a minute to charge it, similar to the preparation time for Itachi's Amaterasu or Kakashi's Kamui.
However, Orochimaru believed that as his mental strength grew, the preparation time would decrease.
Once released after a full charge, the space within a five-meter radius of his target would freeze entirely. Only Orochimaru and those he physically touched would be able to move freely within it.