Watermark 2 X And Ymichel #s 425 - 429

does Wmk 2X and 2 Y regarding this series of stamps designate horizontal or vertical gum or does it describe a horizontal or vertical watermark?

regarding Michel #425x-#429x and #425y- #429y

You can find the answer here

https://www.germanstamps.net/wmr-rpst-1928-coat/

The images on the website NSK references makes it look easy to separate x from y based on the watermark. Not so in real life.

The best way is to look at the back of the stamp for the gum ridges. These are very fine closely spaced lines. You can usually see them even on used stamps. Horizontal lines is y, vertical lines is x.

Another technique is to hold the stamp in the palm of you hand and wait for it to warp, like an arch. If the high portion of the stamp is vertically oriented it's x, otherwise y.

429 only comes in y so you can use that as a guide.

cha ching awesome thank you very much

I note that nowhere in the title or body is there a description of what series this thread is about, let alone country, making it a dead resource for anyone with a similar question in the future.