I can post more pictures of the sword. I apologize in advance for the bad shape of the blade, it went though a house fire years ago and has been in rough shape since.
Thank you very much. Can I ask how you were able to tell it's sadashige? The first kanji looks very different to me but I'm new to this and want to understand.
I believe the side with the most characters reads "8 month lucky day 1 year of Tenna (tenwa) era", but I'm not certain. As for the other side I'm not sure. Thank you for any and all help.