The Kusari Gama is a weapon used in Feudal Japan by Ninjas.
The Kusari Gama is a Kama (or Japanese sickle) which is attached to a chain with a heavy iron weight at the end. The user could attack with either the chain or the sickle, but it's ideal use was to tangle the enemy's weapon in the chain, then move in to strike the disabled opponet with the Kama.