That would, I think, be a very unusual use of FSF. FSF is usually played by responder, not opener. Plus I don’t understand how opener, having made a nf 1S ( it may rarely be passed but it isn’t forcing in normal methods) can now, after partner bid 1an(denying any primary fit and ,Ii ting his hand) can suddenly force with a possibly artificial bid How does one bid, say, AJxx void KJxxx Axxx?