The inverted surcharges above seem to be regularly issued as they are seen as frequently in the market as the normal stamps. P

The inverted surcharges above seem to be regularly issued as they are seen as frequently in the market as the normal stamps. Probably a printing error that was so common the post office simply sold as normal stamps. We include both types in the year set. The surcharges are arranged in a checkerboard pattern so some collectors also wish an entire sheet to show the printing arrangement.