Just wondering if my two-weapon shielded fighter (from APG) could apply the feat weapon focus, and all the goodies that spring from that tree, to his shield as used in a shield bash attack, and would that require any prerequisites other than what weapon focus would normally have. I ask because weapon focus states that you can take it for unarmed strike, but you would still need imp. unarmed strike to avoid AoO. I'm wondering if a shield bash would work the same way, but Weapon focus doesn't expressly state that you can, so what's the consensus Pathfinders?