Hello all, I have developed a liking for these large backsaws, (this one being 18inches) and particularly the earlier ones with the large, full cheeks. BSSM has a mark similar to this dated at about 1825, but I am happy to go up to 1830 on this saw. Until I looked at an enlargement of the photo of the mark, I did not realise that that there was writing below it. I have since cleaned up the back a little and the word to the right of the mark is "Sheffield". There is a letter to the left of "Sheffield which I think that is a "D." If it is the last letter of the word it should be "warranted", although it is so faint that even with extra cleaning I may never be certain this. Fred