Half moon knife

A half moon knife also head knife, round knife are all modern terms to describe is a leather worker's tool consisting of a curved blade atop a handle, giving it a profile similar to that of a mushroom. Medieval terminolgy for the same tool includes trenket or tranchet from the Old French] trechet.

In medieval images they may be seen with a spike on one side which may have been used as an awl when sewing shoes.

The half moon knife allows the cutting of curved shapes necessary when making shoes but needs to be kept very sharp to do so.