Pronounced As: blaznr , science of describing or depicting armorial bearings. The introduction, since the Middle Ages, of artificial rules and fanciful medieval terms has complicated the science, particularly in England. The chief part of blazonry is the description of the escutcheon, or shield, the essential part of the coat of arms. This involves the description of the color of the field on which devices are displayed. Arms are identified by their charges; the most common of these, the ordinaries, include lines of division, e.g., a cross, a chief (a band occupying the top third of the shield), a fess (a band across the shield in the middle), and a bend (a diagonal band). Other characteristic charges are heraldic animals or flowers, e.g., the lion, the fleur-de-lis, and the trefoil. The arms of younger sons should, in theory, show differences; thus a second son should display a crescent in his field. The bend sinister (a band from the upper right to the lower left of the shield) is not a difference and does not necessarily (as is popularly believed) indicate illegitimacy, which is usually blazoned by a wavy border around the shield. Blazonry also involves the description of the crest above the shield and of the motto. The tinctures, or colors, used in blazonry are gold (or), white or silver (argent), red (gules), blue (azure), green (vert), purple, and black (sable). In England, blazonry is regulated by the Heralds' College.