Geoff, you are right, from my photos it certainly looks like a blade irregularity. Don't know if this is photo disturbance or real. I will have to go back and look. Bob, I am going out on a limb here but I think that arsenal stemp is the stamp for SEKI and in the lists there was a smith with the name of NAOTANE. It gives his real name but of course I can't read it. Doesn't give the first name. These smiths produced good and bad blades but mostly showato according to the reference I looked up about Seki. David
