Japanese sword, real or fake?

[wve]

Ho guys, can you help me or refer me to the right place where can I ask this? My grandpa loved to collect Japanese things and he had this sword. I'm wondering is it a real sword or something fake? What is that? What do these letters mean? I'll be very grateful for any help! Thanks!

 

[Uncle Frank]

Easier to read.

 

[wve]

I'm sorry, I don't know Japanese. Can you translate? And do you know is it a worthy thing? Real sword or fake? Thank you!

 

[Uncle Frank]

Not sure why no one has responded? I posted the picture in hopes someone would reply. To really identify swords , I believe the handle has to be removed to see markings under the handle. I wouldn't try that unless an expert recommends doing it. Hopefully someone will let you know something soon.

 

[Toritoribe]

The inscription is 山本大佐 Colonel Yamamoto. It's quite unusual that the owner's name is inscribed especially with his rank (the rank can be changed, as you know). Also, Damascus steel-like pattern appears on the surface. It doesn't seem to be authentic to me.