So, I got a lot of interesting answers to my previous post, this is a Mino tanto from the Muromachi period, and it is "無铭" on its registration certificate, but recently, I found that the word "一" appeared on the side of the "铭", I am not sure if it is a scratch or half of the word, and secondly, at the end of the blade I found a huge fingerprint-like pattern, both sides, but compared to the real fingerprint, it is too large
ps: left one is my fingerprint comparison