Recently I have been collecting Portual III V and X Reis from the 1700's. I have not seen many errors (much more common in Brittish and French coins), but I did come across this one the other day. First, this is the coin well struck. Note the "I" in Ioannes. Now here is the interesting one, so many cracks that the middle of the die flexed and did not strike. The bottom of the "I" is now missing. Here is my attempt at some close ups....
Hi Ed You might think so, but recall the "well struck" photo. There should be a field there yes? In fact it buglges out in that whole region. It bottom of the I and just under the O the metal should be struck into a field, but instead rise higher than the top of the I and O. That is not normal wear. Normal wear would wear the I and O before it got to wearing the field. Note this pic here, you can see the leaf in the crown is cracked in half, the two would be fields that were never struck as well as an additional die crack on the right. I think that its the die that flexed and gave way not wear that account for the bulge in the coin. It was not a bad planchet. if it were well struck as I said, these "fields" left and right of the crown would be the last part that would wear rather than the first. IMHO of course. I was not there...