License plates with low numbers are much sought after. But what about covers with low registry numbers? Aren't they just as desirable? Well, you'll have to decide.
Here's a cover with the optimum low registry number -- No. 1. It is all the more remarkable because the number was written in the space provided for the registry number in the registry handstamp. At least 95% of the covers I've seen have the number written outside the registry handstamp.
I also like the usage. The cover was posted at Heinerscheid, May 23, 1922. The Heinerscheid FSPL type 32 double-circle cancel is uncommon, even though it was used from 1910 until mid-October 1940. (Heinerscheid was never issued a type 33 bridge-and-bar canceler.) The cover was backstamped at Echternach the next day -- May 24, 1922.
The 25c Marie-Adélaïde definitive pays the domestic 20g letter rate; the 50c pays the registry fee.
How many number ones are in your collection? No, I don't mean how many of the 10c William III 1852 issue. These number ones are considerably scarcer!