Hello Jacques,
I've subsequently seen some examples of attributed to the Kanefusa school (Mino, isn't it?) that are given a date, though there is nothing other than the signature. Have you any idea what criteria is, or has been, used to date those pieces? I, personally, can't tell from the signature if there is a difference in the characters with the different generations - I'm not that good and neither is my vision any more, nor have I seen enough examples. I've collected Japanese tea bowls (chawan) for some time now and often, such as with Raku bowls, there have been many generations of the family that have made them. With each generation the seal or signature stamp has changed - sometimes subtly, sometimes significantly. I gather this is not the case with the swordsmiths? Is there a way to get an accurate dating on an older piece that would be agreed upon by more than one person?
David