藍羅紗藤紋陣羽織|Surcoat (jinbaori) - Public domain photo of museum object

A surcoat is a garment worn over armour, typically in the Middle Ages. It served both practical and decorative purposes. Often sleeveless and reaching to the knees or below, surcoats provided additional protection for the wearer's body and armour from the sun, rain and other elements. They were also used to display heraldic symbols, coats of arms or other insignia, helping to identify knights and their allegiances on the battlefield or during tournaments.