As far as I can tell, the only blade length limit in Virginia is 3" on school grounds. Switchblades, however, are not legal if concealed. This should probably be in Legal&Political.
There doesn't seem to be a length for open carry given and concealed carry is prohibited. The problem occurs when you parse what "open" means. Is carried in a belt sheath "open"? Is the pocket clip being visible of an auto with a clip enough for "open"?
I was lookin at this nice italian stilleto switchblade.. I wasnt sure If I was going to buy it for legality issues.
and in that link it says carry legal... and for virginia it says Y3,4, whats that mean?