I am somewhat familiar with the grading system of the National Hardwood Lumber Association (NHLA).
FAS (First & Seconds)
1F (one face)
There is another system that does not appear to be standardized amoung suppliers, but is based on furniture use. Each supplier has their version, so the following is from only one.
Another supplier has the following
Does anyone have any background on this other grading system out there? I know that Superior is usually defined as FAS. It appears that this grading system was devised for furniture/cabinet makers and often comes from suppliers of specific species like Alder or Beech. It appears that the grading system may change based on the species.