[Curator Note:] This definition is not quite true in practice. A g variant seems to indicate that there is a circular region in the center of the grid that may or may not contain a numeral. If a numeral exists, then the -1 variant is added.
The following cancel is classified as Type 6egpr-1 (C+)
The following cancel is classified as Type 6
The above example is provided to show a normal killer grid (without a numeral)
in comparison to the g variant.
The following cancel is classified as Type 6g
Since there is no numeral within the circular region, the cancel is not
identifed as a "-1" variant.
The following cancel is classified as Type 6gp-1 (27.5mm dial) [S-22d]
There is no special variant code for a Type 6 grid with the numeral inside a
circle inside the circular region. By the way, it is the cancel that is blurry -
not the scan.