The term earliest known use, or EKU, is the first date on which a stamp is used. In a perfect world, the earliest known use of a stamp is the same as its first day of issue (FDI). However, the world is not perfect and there are several reasons why the two dates may not be the same. But first, a little explanation of what it takes to be a collectible EKU stamp.
Most, but not all, earliest known use stamps require these components in order to be considered a true EKU:
- It must be postally used. As such, it cannot have been favor-canceled whereby a postal authority legitimately, or illegitimately, dated the stamp without it going through the mailstream. It would be too easy for an unscrupulous postal clerk to cancel a sheet or two of stamps and sell them as EKU stamps. Ideally, EKU stamps would go through the mail to their intended destination.
- By definition it requires that a date of cancellation appear on the stamp and/or the cover to which it might be attached. Without a valid postmark, there is no way to prove when the stamp actually went through the mailstream.
- If the cancel date is not on the stamp, the stamp must be tied to the envelope by the cancellation. If the date is not completely visible on the stamp itself, the stamp must appear on an envelope or postal card where the cancellation clearly ties the stamp to the cover. Without this requirement, a stamp could have just been stuck to an older cover and appear to be issued earlier. The cancellation is what validates the date the stamp as used.
There are a couple of reasons why an earliest known use of a stamp can occur before the first day of issue for the stamp:
- Accidental causes. This is probably the most likely cause of most EKUs. Postal authorities get stamps in advance and sometimes clerks just forget and sell the stamp over the counter before it is officially released. With thousands of post offices in a country, it can easily happen.
- Illegal activities. If sheets of stamps are stolen or slipped out the back door of the post office, and used prior to the first day of issue, these stamps can become earliest known uses. Also, an unscrupulous postal clerk could theoretically backdate a cancel and create EKUs at will.
Also, there are a few reasons why an earliest known issue for a stamp can occur after a first day of issue for a stamp:
- Changes to stamp formats. If a postal authority releases a variation of a stamp that creates a new type, with a perforation change, for example, the earliest known issue for that variety would be different than the original first day of issue.
- Losses of early issues. For older stamps, the earliest known use of a stamp may be after its official issue date because there are few copies that exist. Early issues may not have been collected on-cover, and thus there are few examples.
- Lack of demand. If there is no demand for a stamp's first day of issue, the earliest known use can occur later. This would probably only occur on expensive or unusual denominations on stamps issued in small quantities by remote countries.
Searching for earliest known uses of stamps can be an interesting aspect of philately. Be prepared to look through lots of covers if you ever hope to find an EKU.
Previous Terminology Topics:
- Coil Stamps
- Common Design Stamps
- Forever Stamps
- Air Mail Stamps
- Semi-Postal Stamps
- Commemorative Stamps
- Definitive Stamps