...absolutely require background checks on all firearms sales. Yes, it's probably the case that exchanges between two private parties will sometimes be conducted "in the parking lot" as it were, but that sort of violation of the law (Oregon has universal background checks) occurs outside the gun show realm, too. The majority of sales are by gun dealers, and they're highly unlikely to risk an unchecked sale (huge penalties).

In my "other home?" Mostly, gun sales don't happen at all...but those that do have a level of paperwork hoop-jumping that makes the US system look like a complete free-for-all. Japanese bureaucracy has to be experienced to be believed.