Here's the Sangot, or sickle. Started life as an agricultural tool, but has many lessons to teach about evasion, turning, and finding emptiness ... as in learning to be where it's not .....
Here is a design made by Sonny from a tool, with a handle fabricated from leather, sawdust, and crazy glue amongst other things.
The second is a training version of the same with a carved handle indicating different orientations of the hand.
The edge is on the inside of the curve.