in many systems of heraldry, the arms of each living person must be unique. english heraldry has used armorial variants to distinguish the arms of brothers from their father's arms and from each other since the 13th century; this is now normally done by the system of marks or "brisures" set up by the early tudor herald john writhe. canada adds a unique series of brisures for use by female children who inherit arms. as in other heraldic systems, these cadency marks are not always used; in any case, when the heir succeeds (in canada, this is normally the first child, whether male or female, according to strict primogeniture; however, the grantee may choose another person as heir), the mark of cadency is removed and the heir uses the plain coat of arms.