This is the Sickle design – The embedded Sickle known as the ‘sica’.
The blade was sharpened only on the inside and was reputed to be devastatingly effective.
It was capable of splitting a shield in two at a single blow and then pierce the armour.

The 3 leather tied plates here commonly known as Plate Armour, or Lorica Sementata (segmented) consisted of covering the body with dozens of articulated metal plates. This protective design gave rise to the term “Knight in Shining Armour”.