Czeslaw Miłczak for 20 guilders 1932 described as many as 13 different varieties of patterns, but did not record one like this!
This is a circulation pattern for a standard (not fractional) series. As many as 6 different varieties of patterns are noted for this type of series (and considering the series letters it is even 8), but they are all with zero numbering. There are none with circulation numbering specifying the range of numbers within the variety (here from 1 to a million). This type of circulation pattern is noted only for fractional type series, such as C/A 000,001 - C/A 750,000 or C/B 500,001 - C/B 750,000, etc.
Acquired in the upper margin an additional numerator with the digits 12,345, probably placed to show the typeface of the digits. In addition, there are also acceptance annotations in the margin that look like an order number and date.
Very nice state of preservation, visually unchallenged and with a PMG rating of 50.
Great rarity, most likely unique for the moment!