Forgive me being pedantic 1949! but don't you mean a "die blemish"? If there was a genuine die error in the modern era it would be remarkable and valuable, as witness the 1983 2 NEW PENCE error. (Though strictly speaking, even that is not a die error, but a mule - I'm finding it hard to come up with an example of a die error in modern times). Yeah.......I suppose. I'm not really sure what you would call mine either, and I'm very open to persuasion on this one. It appears like a little bubble in the upper field of the reverse. Die "blemish", as you suggest, maybe ? Or other blemish? E.g. on the blank itself? Or a bit of grease or foreign matter that got in for just one strike only?