Being an avid collector , you first start with types, then the known/standard varieties such as signatures, watermarks, replacements, etc. and when you run out of those you start searching for supplemental material and/or new varieties. That being said, I sat down with my Ukrainian shahiv notes the other day, organizing labeling, studying as one would normally do and while making a determination on whether or not one of my 50 shahiv notes was a contemporary counterfeit and comparing it to a few authentic notes I noticed a difference between two of the authentic notes.  

The backs of the two notes were different, not significantly so but different none the less. The text " Ходить / нарівні / з дзвінкою / монетою. " ("Walks along with the ringing coin." is what Google came up with, but most likely translates to "Circulates along with metal coins.") is slightly larger on one of the notes, with some of the individual letters having serifs. The Tryzub also varied with one being noticeably larger, with a larger (wider) center prong and slightly larger teardrop opening. My first thoughts ran to one or both of these being a contemporary counterfeit, but both have a quality of design and printing that is on par with authenticated examples, along with the paper looking good as well. For now, I'm going with there are two varieties and I'm going to call Variety A, small text - large Tryzub, and Variety B, Large text - small Tryzub. ST/LT and LT/ST for short. I was very confident that both were authentic but looking for a second opinion I searched for PMG graded examples of each variety. Found them!

Large Text - Small Tryzub. (1530318-026)

Small Text - Large Tryzub. (2020786-042)

Let's dig into the details now shall we. The front of both notes look nearly identical to me and have none of the telltale signs associated with counterfeits of the time. Below are front and back images of each variety, left top and bottom, and side by side images of the front and back of both notes. The ST-LT note was more heavily inked obscuring some of the design elements, I think, if you look very closely you will notice this. It is possible that the two fronts are different but, for now, I think not. The differences on the back are more noticeable and become obvious once noticed. We'll dig further into that next.

Both notes were scanned together, front and back / side by side, and the scaling has not been changed. I edited out the edges and, again, placed both side by side. The front are again identical, or at least nearly so, but the backs are not. The ST - LT note's back design is taller and narrower than the LT - ST note's back. The text on the LT - ST note is noticeably larger and of better "craftsmanship" with serifs on some of the letters, equal spacing and varying thicknesses within individual letters. The ST - LT text is much blockier and more basic.

Sizing variation. 

Text cropped and enlarged for easier viewing.

The Tryzub on the the back of the ST - LT note is overall larger, with the center prong being wider with a larger/taller center teardrop opening in the design which extends further towards the tip of the prong. The Tryzub on the LT - ST note is smaller with a narrow center prong and smaller/shorter teardrop opening. There are other differences in the design, mainly brought on by the size difference, but the center prong and teardrop opening are the most noticeable/easiest identifiers. Below are enlarged images of the two Tryzubs with identifiers noted, and overall size variation dimensions. 

I've looked through several reference books and while none recognize either variety, images of each are used in these references. In Paper Money [of] Ukraine the 50 Shahiv images used are of the LT - ST variety, and in Ukrainian Paper Money images of the ST - LT are used. It seems that the references have accepted both varieties but acknowledge neither. I find this normal, as typically only American collectors are obsessed with varieties.  

I'm very confident both notes are authentic and that PMG has graded each of the variations is additional verification, but there is always a chance that one could be a counterfeit and until I can find additional confirmation in a reference, or a second set of eyes to verify, or get PMG to recognize the varieties it's not a done deal. I'm also looking for this same variation in the other Shahiv denominations but it seems that the ST - LT variety is dominant throughout the other issues. Although, I have seen images of the 40 Shahiv note with these back design varieties. I now only have one question, why? A reprint at a later date? An unauthorized issue? A modern counterfeit? Personnel? Equipment? Etc......  All I know is that I'm adding a new variety to my Shahiv variety list until proven otherwise.