After World War I, there was a law passed that products coming into the United States had to have a provenance mark. The earliest marks just state country of origin. The later marks added words in English, such as "Made in". Still other marks included a company's or an exporter's logo. In today's art glass antique market, provenance marks are passed off as "signatures", which they are not, since they do not indicate the company that made the glass but only the country of manufacture.
When it comes to Czech glass, there are plenty of marked pieces, all corresponding to post Art Nouveau, Jugendstil production. We do know Loetz employed two such marks in its later glass items for export (see Loetz 4: Tango glass). A great number of Kralik items also appear with distinctive markings, comprising both Tango and Deco period vases. Two such marks are recognizable as Kralik. The first is the word "Czechoslovakia" in a semicircle, and is documented in the PMC VI: 43, :
1. Semicircular mark
So far, we have two fan vases with the semicircular mark. However, Tom Rood has the same vase, in pink, with a straight line mark:
3. Tom Rood's vase
And to make matters more interesting, the same fan vase, in green, has appeared on internet with two marks, both semicircular. The alternate spelling shows the vase was marketed both in English and in French:
4. Vase marked twice
Thus, we have a vase marked two different ways in two different spellings. The semicircle and the straight line can be both safely attributed to Kralik, as are both spellings of the country of provenance. Some marks are more arched than others, depending on placement on the vase. The pieces below come from private collections and from internet:
7. DL 1
The next group of examples comes from the internet.
18. INT. 1
19. INT. 1M
Other semicircular marks have been found, both pressed in the mold and hand etched (which may be spurious). They are not to be confused with this particular mark. If anyone has pieces with this particular mark, I'd appreciate a photo of the piece and a photo of the mark.
On the subject of photographing marks: it is notoriously difficult. I have found that using the macro setting is worse than just using a normal opening and not really getting very close but using editing: cropping and contrast--to highlight what may be quite a faint mark. If you can't photograph, I'll take your word for it!
Another comment: so far, no "Made in Czechoslovakia" semicircular mark has surfaced. It may mean that the mark under analysis is an older mark. Whenever the mark appears in a piece, it identifies it as Kralik and also identifies any unmarked piece in the same decor.