Board Thread:Theories and Speculation/@comment-29332822-20170111104029/@comment-35622277-20170116165323

Sasuke sword was shown previously cutting through things regular steel cannot. Rocks, metal, etc. without any lightning enhancement. Then it fell into the lava pit in Kaguya's dimension. Obviously he retrieved it from the fires of hell, reforged as Sword of Kaguya, and is no so overpowered, not even Naruto's first layer of plot armor could defend against it.

But seriously, I'm pretty sure Kishimoto just forgot. Unless Shin made the sword move so fast it broke the sound barrier and went Mach 15 high-hypersonic speed and cut right through his SPSM cloak.