This is a Tanto that was given to me by the widow of my best friend that died a few years ago.  He loved the Japanese swords, and unfortunately I know little of its history.  I did have an expert look at it, who determined it was made from a cut down (or broken) WWII Japanese sword.  The polishing is not correct, the shape of the blade tip is a bit off, but the parts are all authentic and someone put a lot of time into this piece.  The collar was noted as being very unique.

Bryan