The sakabatō (reverse-edged sword) is a type of strange katana sword which has an upside down blade - the sharpened (edge) and unsharpened (back) sides of the blade are transposed.
The sakabatō seems to be a weapon of peace. On the normal katana, the outward curved side of the blade is sharpened, while the inward curved side of the blade is blunt. In contrast, the sakabatō is designed as a simple katana with its blade forged on the opposite side than normal, making it a sword ill-fit for killing. The sharpened edge is the inward curved, longer side of the blade, making it hard to differentiate the cutting edge from afar. It generally knocks the wielder's enemies "senseless" rather than killing them, which is used normally would only inflict blunt force trauma which can't cut or kill. The only way for the sakabatō to cut is to rotate the hilt by 180 degrees within the hand, thus holding the sword backwards. Its fittings are humble and simple, but vary upon depictions throughout.
This reverse bladed sword is used by a fictional character- Himura Kenshin who wields a sakabato to uphold his vow never to kill, yet still protect his friends with his sword. Sakabatou may not be able to kill you, but he can still beat the shit out of you.