So as you attempt to compare the two societies they are Apples and Oranges and no Japanese nor Norwegian societies would work here seeing America is the third largest populated country in the world with Fifty States and is a damn melting pot!
I know you will disagree but when you have a melting pot society like America has, well you will have problems...
Here's the main difference.
America lets average citizens own guns.
Japan has banned private gun ownership since the Meiji Restoration (when they got sick of people raising private armies).
The Japanese are more like us that we care to admit. The should be, they've spent the last 100+ years trying to be us.
To try to blame melting pots or video games for the problem is just silly.
We have a problem because we've decided that gun ownership is a "right" like voting or freedom of speech, which means that we've put a very high hurdle into taking that "right" away.
And we get exactly the result we got on Feb. 14. Someone who everyone agrees now should not have been able to get a gun was able to get several, and killed a lot of people.
Again Japan is a Island Nation and is a lot smaller in population than us and no the Japanese culture is not like the American culture...
They may try to be like us in some ways but tradition is strong in their society where it is lacking in America.
Also America is a mixture of cultures and not just Japanese.
Also your argument is the private citizen does not need firearms to live in this country, well I can tell you the rural population need them.
Why?
Simple, I live in Texas where wild boar ruin land and coyotes and wild dogs can kill your livestock.
Now you will tell me to call the local police or animal control but in some places it is a hour away before they can get there.
So what do I do?
Well according to you I should not have my shotguns ( pump action and single shot ) and should my land and animals be destroyed.
Then living in some rural parts of Texas you have to deal with Cartels and Mexican Gangs that want to use your land.
Now you would again say call the local authorities, and again you might have to wait an hour and by then those Cartel Members or Gangs have killed you.
Now I know in your urban simple minded way you do not care about rural America ( which is why Trump got elected ) but guns are a tool for protection and no matter how much you disagree they will be part of life.
So as you try to shame gun owners for owning a tool to protect themselves from many things in life, well thank God you are not in power to change things because you would get innocent people killed more than what have been killed so far.