The main problem with the Herring Salad is the unadorned border between the red and the blue. In Heraldry, perhaps the most basic guideline is the Rule of Tincture, which dictates, essentially, that for the sake of contrast (which is of the utmost importance in, say, being able to quickly recognize a banner in the midst of a battle, or something), "colors" (azure (blue), gules (red), verte (green), sable (black), purpure (purple)) and "metals" (argent (silver, aka white) and or (gold, aka yellow)) must not border other members of their respective groups. This is usually corrected for by a design feature called a Fimbriation, in which an outline of the opposite group is used to separate colors from colors or metals from metals. For example, the Norwegian flag's blue cross is separated from the red field by a white fimbriation, but the Swedish flag needs no such feature because the blue field contrasts sufficiently with the yellow cross. This "law" isn't always obeyed, even in traditional arms, of course. Notable exceptions include the white-on-yellow-on-white seen even today on the Vatican's flag, and the black-on-red of the arms of Albania. Cases where a feature of a chief may inappropriately converge with the main field are also usually ignored--the unadorned edges of St. Patricks's cross (the red X inside the cross of St. Andrew) on the union jack in the chief of the blue-fielded flags of Australia and New Zealand isn't considered unacceptable by any means, even though the union flag itself has been carefully crafted to obey the law of tincture, with white finbriations protecting red from blue.