Hi Ken, Muromachi was my impression too. The spacing between the mekugi Ana is relatively large, so the original blade length was above 70 cm for sure. I don't even think that the lowest mekugi ana is the original mekugi ana. I think it's lost when the blade was shortened.
I have read several threads about taking pictures of blades but in reality it's not that easy. Thanks a lot for your reply. I really appreciate it!
Best regards, Ed