Point of difference
Most new SCA arms must display two points of difference from any other extant SCA arms in order to be registered. This is based loosely on the amount of change seen in period heraldry between non-related persons and helps prevent confusion or presumption.
The rules for conflict checking can be complex, but some of the ways to create difference in a device are:
- Add or remove a charge group
- Change the tincture of a charge group
- Add a peripheral ordinary
- Change the field
- Change the posture or position of a charge when applicable
In most cases, charges are cumulative. The exceptions are field changes and changes to tertiary charges, for which only one difference can be derived even with multiple changes.
The exception to the "two points of difference rule is simple heraldry. Simple heraldry is uncomplex, often consisting of a single charge or group of charges on a field with only the most basic of divisions. When a device is considered simple heraldry, only the type of primary charges needs to be changed to clear conflict, even if this means there is but a single point of difference.
On rare occasions, clear differences are trumped by a visual conflict. This is related to guidelines sometimes referred to as the ten foot rule, in that the points of difference must be obvious from a distance of ten feet.