To try and answer this question we have to first take a look at the 1651 silver crown, made towards the end of 1651 in very limited numbers. So let’s get started here are some 1651 crowns.
1 2 3
4 5 6
The totally re-designed 1651 crown after the failed designs of 1649 alongside two examples of what are often referred to as 1652/1 crowns.
Images 5 and 6 show what appears to be a faint digit 1 under the large digit 2. This is usually the defining feature which some pounce on. But could that maybe be a faint small 2 under the large 2 ? Another question which arises is why use a large 2 to cover a small digit 1? Wait a minute the 5 looks to have changed too!
Images 5 and 6 also appear to have a small 6 and a small 5 over a larger 6 and 5. Notice also in image 6 a small depression between the 6 and the 5.
One final difference is the letter V above the reverse shields. In image 5 and 6 it is a larger, different shaped V.
A detailed comparison can be made by super imposing images of the reverses. The first row of images is 1651, crown image 1 super imposed on 1651 crown image 3 to test the process. Matching up the positions of the stops and the shields leads to good overall alignment within the limitations of the hammer process. The second row super imposes a 1652/1 crown, image 6 over 1651 crown image 1. It is not possible to align these images therefore the 2/1 die does not originate from the issued crown of 1651. Moreover the variety of digit 5’s in use can be clearly seen. The central transparent images clearly show that the size and shape of the V above the shields is quite different. This occurs thru’out the crown series suggesting that there were two sets of punches being used to make the reverse dies. The harp punches are also different.
So the correct description for this coin should perhaps be 652 over 651, instead of just 2/1, or maybe 1652 crown, large 2, fine beading. Then there is an often unrecognised variety of 1652, with both a very large 2 and coarser beading -