Underarm (Original Latin: Sub brach) is an term used to describe a type of middle guard or ward in historical swordfighting.
Arming Sword and Buckler
The term is applied to the ward relating to the 1st Ward of the Royal Armouries MS I.33 although the term itself is not used in the manuscript.
The 1st ward is taken up by standing right foot forward, buckler held near the waist facing to the left. The sword is held in the right hand, tucked under the buckler with the long edge facing out (second position) and the point down and towards the rear.