foreign bought Unlocked N95 8gb usable in japan, softbank?
 

any one knows if its usable? an unlocked nokia N95 8Gb, usable with my current softbank sim?

Not based on my research. You can look at the following site and compare your phone spec to see if its compatible:

Japanese Cellular Phones FAQ

While the site is old and probably outdated, I think most of the information is still relevant

N95 specs: Nokia N95 - Full phone specifications

Good luck