hi mark
I will take a wild guess on this blade I know I'm right on target from what I see with the tang and original signiture the color of the steel and shape tells me its probly the above dates I stated so whats great about the Hawley Japanese sword smiths it can narrow down all the tadayoushi smiths from this early era most of them are 15 point smiths you can rule out any tadayoushi smiths that made after year 1650 it is not years 1500s 1700s or 1800s hope this helps you last in my opinion the Hawley Japanese sword smiths books are the bible for Japanese swords have a great day andy militarynut