Japan is possibly the worst country to cherry-pick violence statistics from. Following WWII, the country was forcibly disarmed. If you want to pick a "castrated-by-the-USA" country, they would be the #1 pick. If it wasn't for the US and its "gun culture" as some put it, Japan, along with Germany, would long ago have removed ALL free men's right to bear arms, along with most other rights.
Japan and Germany are among the worst, but not the only countries of defenseless impotent men that the gun-grabbers love to cite as a model for the USA to follow.
They also use the UK and Australia/New Zealand to 'prooove' that gun grabbing is legitimate and works, forgetting that the people in those places are not free, having never fought or won a revolution and War of Independence, and are thus still serfs, peons, and subjects of the Crown.
OTOH, Americans own themselves and are not property of any Sovereign King or Queen. Hence our concomitant right to keep and bear arms, plus its associated costs and benefits.
Japan, Germany, and the rest of our paper statelets are lucky we didn't feed them to the Chinese Dragon or Russian Bear, instead preferring to teach them about democracy, baseball, and value-added manufacturing.
We'll give the samurai their swords and the Hun his axe back when the time is right, unlike the Royalists who will never allow the peasants to be armed.