Backsaw

A backsaw is any hand saw which has a stiffening rib on the edge opposite the cutting edge, enabling better control and more precise cutting than with other types of saws.

Backsaws are normally used in woodworking for precise work, such as cutting dovetails, mitres, or tenons in cabinetry and joinery.

Tenon and dovetail saws usually have a pistol grip style handle which may be open or closed at the bottom.

These two immediately incompatible requirements are resolved by swaging (and perhaps, spot welding) a stiffening cap over the length of the top edge of the blade.

This thickening of the blade is the back and is generally made from some kind of metal, usually brass or steel.