Also called in French clinches, cliques, Chaines de Jacques…

This form of arms protection was light and highly mobile. This offered the perfect balance between efficiency and minimum weight.

They were much appreciated by crossbowmen, billmen, pikemen, and all the infantrymen who wished to protect their arms at low cost and without weighting themselves down. They were even sometime worn by men-at-arms or knights in specific circumstances, such as climbing the walls of a city.

« To properly equip a footman, either a crossbowman or a handguner, the said fiefs and sub-fief will be required to have a haubergeon, a lights sallet without visor, a gorget and some jack chains for the right arm.” Ordinance of Charles the Bold (Salins 1473)

« Pikemen should wear small haubergeon with sleeves, breastplate and on the right arm they should wear iron strips with small guards (ie : jack chains)» Ordinance of Charles the Bold (Bohain en Vermandois,1472)