Flag, Ensign: Imperial Japanese Navy (FLA 5500) The main flag of a ship of war is its ‘war ensign’, which identifies its nationality. Used since 1889, the Japanese war ensign, like those of Great Britain and France, has not changed design since the end of the Second World War. Copyright: © IWM. Original Source: http://www.iwm.org.uk/collections/item/object/30018036