Looks to be a katana cut down to wakisashi length, then shortened a bit more at that point. Signature was probably lost to the cutting-down. Not a military sword to my eyes. Oil the heck out of it TODAY, if yesterday is not possible, and regularly wipe down until no more loose surface rust is left. Then keep it oiled. A polisher might be then able to do a "window" to check temperlines, grain, etc.