This is kusarigama, and this is not some kind of curse, but a formidable weapon of the past. Kusarigama consists of a sickle, to which a shock weight was attached with a chain. Moreover, the length of the handle and the blade were different, but the most popular model had a ratio of 60/20 cm.
The sickle blade is perpendicular to the handle and is sharpened from the inside. You probably already guessed how they wielded this weapon. The technique of working with kusarigama made it possible to strike the enemy with a kettlebell, confuse with a chain, or with a sickle. Multifunctional little thing. In addition, it was possible to throw the sickle itself at the enemy, and by pulling the chain, return it to yourself.