The topic this time is Heraldic Group Theory. This is a model to describe how the various groups of charges in a coat of arms relate to one another. Not only is an understanding of charge groups essential to conflict-mongering, but it is used in blazonry as well.
But first, a warning. The model I am going to describe is an SCA invention. Usually that is a criticism, but not in this instance. Most SCA inventions stand in place of period practice: group theory describes period practice. Some years ago I did an analysis of medieval English arms in Foster's Dictionary of Heraldry. I was able to use this model to describe over 99% of the coats. The caveat is that like so much in the SCA, this theory was not designed so much as it evolved. Its current state of evolution is not, in my opinion, complete: precedent has not entirely accepted its implications. I will be describing the model in its full glory as I interpret it. Honesty requires, however, that I make clear what is established SCA practice and what are my own drug-induced ravings. (The drug, in case you were wondering, is caffeine.)
The essential idea is that every charge in a coat falls into exactly one category of group. The official Glossary defines four categories: primary, secondary, peripheral, and tertiary. Rule X.4. implicitly adds a fifth category, of overall charge. In general a group can have any number of charges in it, and they may or may not be identical.
The primary charge group is that which occupies the center of the shield. If there is one or more central ordinary(-ies) this is usually the primary group. For example, in "Argent, a bend sable" and "Argent, two bendlets sable" the bend(lets) are the primary charges. In "Argent, a lion sable", "Argent, three lions sable", and "Argent, semy of lions sable" the lions are the primary charges.
The secondary charge group is that which surrounds the primary group. Therefore you cannot have a secondary group without a primary group to surround. For example, in "Argent, a fess between three lions sable" and "Argent, semy of lions, a fess sable" the lions are the secondary group, surrounding the primary fess. In both cases if you removed the fess the lions would become primary.
The peripheral charge group is that which follows the edge of the shield. This is commonly a bordure, a chief, an orle of charges, etc. It is not necessary for there to be a primary charge group present. For example, in both "Argent, a bordure sable" and "Argent, a lion within a bordure sable" the bordure is the peripheral charge.
The overall charge group is that which surmounts one or more underlying charges. The underlying charge is the primary. In period heraldry the overall charge is almost always an ordinary, and usually a bend. For example, in "Argent, a lion sable surmounted by a bend gules" the bend is the overall charge, and the lion the primary. Unfortunately the popular pattern in the SCA puts the non-ordinary overall, but the underlying charge is still the primary. For example, in "Argent, a bend gules and overall a lion sable" the lion is the overall charge and the bend the primary.
The tertiary charge group is that which lies entirely on another charge group. For example, in "Argent, on a bend sable three mullets argent" the mullets are the tertiary group. To go off into my wild ravings, standard SCA practice doesn't take this far enough. I distinguish between tertiaries (i.e. charges on a primary charge), peripheral tertiaries (i.e. charges on a peripheral charge), and overall peripheries (i.e. charges on an overall charge). There are also secondary tertiaries, but these are extremely rare in SCA practice.
(In my most extreme moments I consider there to be yet another category: the cotisse. In this interpretation "Argent, a bend cotissed between six lions sable" has three charge groups. Someday I will write up my argument for this interpretation. In the meantime don't try this argument at home, kiddies. By current practice this idea is out in left field.)
One useful feature of my scheme is that there can only be one group of each type in any given coat. This occasional matters, and in those cases where it does the conventional interpretation is likely to lead to bogus conflicts. Is "Argent, a bend cotissed sable" only one cadency step from "Argent, a bend between two mullets sable"? I see no reason to believe that this is the case, but this is currently a conflict.
The reason why charge groups are important in conflict is because when we compare to armories we compare the corresponding charge groups seperately. For example, comparing "Argent, a lion within a bordure sable" vs "Argent, a lion within a bordure gules" we count the change to the tincture of the primaries (lions) as one difference, and the change to the tincture of the peripherals (bordures) as another. The point about distinct tertiary groups is illustrated by comparing "Argent, on a chevron sable three mullets argent, all within a bordure sable." vs "Argent, a chevron, and on a bordure sable three mullets argent." Is this zero changes, one change, or two? Precedent is unclear, but by my interpretation it is two: the removal of the primary tertiaries and the addition of the peripheral tertiaries. If, however, tertiaries is tertiaries, then all that has been done is rearranging the tertiary mullets, worth at most one difference.
I will close with the most notable situation where precedent not only hasn't caught up with the cutting edge, but hasn't even caught up with the rules and glossary. Compare "Argent, a fess and in chief a lion passant sable" with "Argent, a fess within a bordure sable." Current precedent has this as a conflict, considering the peripheral bordure to be essentially a special type of secondary. It therefore rules this as a conflict, with but one change to type of secondary. I don't know why this is the case: while more than one Laurel has upheld this interpretation none has explained the reasoning behind it. The rules and glossary certainly don't demand it, and indeed a straightforward reading is inconsistent with it. No one has suggested, much less documented, that this is but one cadency step. I expect that eventually this will be overturned, but in the meantime I can only shrug in bemusement. At least it serves as an illustration of the evolutionary nature of heraldic theory, and how practice sometimes lags behind.
In reviewing what I have written I find that I put in more anarchist ravings than I had intended. On the one hand I consider heraldic group theory to be one of our finest achievements: if the SCA makes one contribution to the modern study of heraldry I think this will be it. On the other hand it drives me crazy that we are so close, but not quite there; hence the wailing and moaning and gnashing of teeth. You will be on safe ground if you think in terms of the five basic categories: primary, secondary, tertiary, peripheral, and overall.
In terra pax,