reverse blade
A type of katana, in which the sharpened side is on the inner curve as opposed to the original construction of a katana, where the sharp side is on the outer curve. That way, when battling, your opponent becomes incapacitated other than cut, lowering a risk of death. Fans of Ruroni Kenshin may have heard of it.
It is also known as the Sakabatou or the Sakaba