Well, Japan has some of the most stringent anti-gun laws of any nation on Earth. Interestingly enough, even though they are a small island nation enough guns still find their way one shore that there are still incidents of gun violence every day. I will grant however that they have managed to slow the flow of guns enough that the criminals have simply resorted to using other, more readily available weapons.
In response to this, Japan is now forced to outlaw samurai swords as criminals have begun using them to perpetrate their crimes. Of course banning samurai swords will only be the first step. billions will be spent to eliminate the scourge of samurai swords from Japan's streets. There will be only partial success, but eventually criminals will resort to using some other weapon in enough numbers that laws will need to be made to outlaw that new weapons... Baseball bats perhaps.
Of course throngs of law abiding citizens across the country will turn in their samurai swords leaving them utterly defenseless against the sword wielding criminals that will simply disregard this law just as they disregard the laws against murder, rape and theft.
Look I don't know how many times I have to repeat myself. The logic doesn't get much simpler and clearer to understand. If you can not see this and understand it, perhaps it is simply time that Mr. Darwin leaves you behind, relegating you to the fate of the dodo because it is amazing that you have the faculties to remember to breathe.