It's always interesting to me to see some of the various sets of rules that different groups establish in order to encourage a particular heraldic style and philosophy. I was reminded of this the other day when I ran across (again) a set of the "Ten Commandments for a Designer of Finnish Heraldry", drawn up by Jukka Suvisaari and amended by a committee set up by the Heraldic Society of Finland in April 1990. These rules are similar to the guidelines that are found for other Scandinavian heraldry in Norway, Sweden, and Denmark. The rules, along with other general information about heraldry in Finland, can be found on-line at http://www.thefullwiki.org/Finnish_heraldry
The Ten Commandments for a Designer of Finnish Heraldry are:
1. Only heraldic tinctures are used. These are the metals, gold (Or) and silver (Argent); and the colors, red (Gules), blue (Azure), black (Sable) and green (Vert). In heraldic drawings yellow can be used in place of gold and white in place of silver. In flags and pennants this is almost always done nowadays. Heraldic colours are bright and clean; tones of the colours are picked from center of the scale.
2. The use of only two tinctures, of which one is a metal, is preferred. The use of a third tincture requires good reasons, but a fourth is definitely bad heraldry.
3. According to the tincture rule, one must not place colour on or next to colour or metal on or next to metal, unless the line of contact is very short.
4. Letters, numbers or texts do not belong on a heraldic emblem.
5. Figures (charges) must be as big as possible and fill the space intended for them as completely as possible.
6. In figures natural presentation is not important, but characteristic is. (i.e the ferocity of the lion, majesty of the eagle, gracefulness of the deer)
7. In principle the charges should be two dimensional. At a minimum they must be recognisable even when presented as coloured flat surfaces, without shading or extra borderlines.
8. A heraldic emblem must be easy to remember. It should not be crowded with too many symbols, only the absolutely essential. The ideal is only one charge.
9. It is forbidden to be repetitive in heraldry: one idea should not be symbolized with two or more charges. On the other hand, if one charge suffices to symbolize two or more ideas, it only strengthens the symbolism of the charge, and therefore the whole emblem.
10. The charges and the whole emblem must be such that they can be redrawn according to a written description (blazon) of the coat of arms or flag without a model. This means that the charge must be a general presentation of its kind. For example, a castle cannot be a specific castle, but only a stylized heraldic castle (although it can be explained as referring to, say, Korela Fortress). In other words, the description of the charge should not require the use of a proper noun.