I came across this for a cheap price at an estate sale, and instantly noticed that it seems to be very old. The blade is not in the best condition, as I'm sure it was used in battle a few times. Looks to be polished many many times. One thing that is interesting is the saya has old Japanese written on the underside of the cover where it has torn and split. I have never seen anything like it. The nakago has a fair bit of age, and some bad rust, and does show faint file marks. The blade measures just over 50". Would anyone know the age and name of this? Would it be considered a Nodachi? I would assume that these blades are rare? Thank you