On reading Michael Marsh’s books on the Gold Half Sovereign. I decided some years ago to
commence an exercise to see what die numbers still existed and to see if the reason for their
adoption could be ascertained. The gold half sovereign denomination is an excellent
denomination to look at as the use of die numbers on half sovereigns occurred over the
longest period, that is 1863-1880 inclusive.
BNS Research Blog 
The author of this article is unaware of recent research published at the end of last year in the British Numismatic Journal 2024. The article “Victorian Die Numbers: Their Purpose and Their Demise” (pages 189-211) gives a comprehensive explanation as to why die numbers were introduced in 1863 and why they ended in 1880. It also undertakes a review of numismatic literature published over the last 150 years, pointing out that many inaccurate accounts have been offered as to the reasons why die numbers began but, equally, that several correct versions have also been written. Brian Unsworth’s article on die numbers and half-sovereigns has been written without reference to any of the previous research on die numbers and offers speculative and inaccurate explanations. It should be revised to take account of the most recent research.