Literally means "Left hand", this is a defensive weapon. Used primarily in conjunction with a rapier, a main gauche is weilded in the off-hand for parrying and occasionally for a thrust. Was fairly popular in the 16th through 18th centuries, mostly for its benefits in a duel-style fight.

While lengths vary as much as any dagger or sword might, it averages around 12-18" blade length with a 6" hilt. There is also usually plenty of hand protection, such as a long (10" or so) quillion, knuckle gaurds, and such. The blade is also a little wider than most daggers, and sometimes sports recessions near the hilt (for trapping the opposing weapon).