Time Barrier, as its name suggests, was a spiritual shield that renders the ability to freeze time ineffective on those touched by it. This powerful ability seems to be used by priestesses of supreme spiritual power, as Kagome's own modern-day possessions were capable of erecting this powerful barrier on their own instinctively when the Mirror of Stillness from the Dream Castle of the Pentacle Mirror in Lake Motosu has been activated under Kaguya's will.
However, this was utilized and mentioned only in the Castle Beyond the Looking Glass and never in the series itself, so it is unknown whether it would be needed again by either Kagome or Kikyō ever again.
Another thing in Fire on the Mystic Isand that Kanade, the priestess of the Hōraijima has built the Cauldron of Resonance with a magical barrier can protects the island from invading Yōkai (especially from Kirinmaru and Zero) that the barrier will fades and holds up every 50 years, until the Shitōshin were among them, as Priestess Kanade fought them and sealed their powers into her jeweled comb box and sacrificed herself into the Cauldron. As Asagi going to sacrifice, Inuyasha survived with his Robe of the Fire-Rat and Asagi has resurrected as Kanade gave him the the jeweled comb box and tells Asagi to forgive her that she made the wrong path. The Cauldron was damaged by Inuyasha's Kongōsōha, later was completely destroyed by his half brother Sesshōmaru with his Sōryūha while battle with Kyōra.
- The bandages and First-Aid Kit glowed with a thin white-green spiritual aura.
- Cauldron of Resonance
- To be overly simplistic, a time barrier only exists around items and people not native to an era. Kagome was not born in the feudal era, along with all her modern era supplies and the locket she gave Inuyasha. So this kept them unaffected by the Stillness spell cast by Kaguya.