A traditional agricultural tool used to harvest whole plants, such as hemp, or wheat. Also used in depictions of "death" as a tool to reap souls, or by other mythological beings.
Although seen in anime as a weapon, the only known use of a "war scythe" is done by flipping the blade to point up and attaching it to a modified handle, to use like a spear as an emergency weapon for farmers and villagers. It was effective against cavalry and fighting in open space, which is common for farmland to have. This tool looks more like a spear or halberd, and nothing like the original. Theoretically however, it could be used as an effective weapon as is.