Norway was has a murder rate 2.5x that of Japan[1]. Norway is considerably less safe than Japan, albeit still very safe by global standards.
[1] https://en.wikipedia.org/wiki/List_of_countries_by_intention...
https://www.tokyoweekender.com/2017/06/sex-crimes-japan-go-u...
https://www.japantimes.co.jp/news/2014/07/31/national/crime-...
Japan also has a huge issue with people admitting to crimes they did not commit. https://www.france24.com/en/20181207-japan-justice-99-system...
@nosuchuser2 said,
"Japan's official murder rate is widely believed to be significantly underreported"
in response to someone noting that Norway's murder rate is 2.5x Japan's murder rate.
None of the articles you linked to even mentions an elevated or misreported murder rate. Instead you linked to articles suggesting that sex crimes are underreported. Sex crimes are actually underreported in just about every industrialized country, US included.
Given that the official murder statistics are what they are, citation is still required
Japan has actually been seeing a rise in crime among the elderly population lately: https://www.npr.org/sections/parallels/2016/11/22/500040363/...
In a country of literal ninjas and samurais, this is the most inconsequential of all the reasons you gave.
https://www.researchgate.net/publication/309755075_Does_Gun_...
I looked very briefly at that study. It compares US cities to other US cities using data from 1990. I would be more interested in how the US stacks up against other countries that don't have to act within the limitations of the Second Amendment. More recent data would probably be valuable as well.
Most difference between crime in Norway and Japan is more likely down to Norway having much larger immigrant population from poorer countries.
I think your attitude easily ends up excusing police states. Japanese justice system is highly questionable. Almost nobody ever gets acquitted in the justice system, and prison is rather harsh. Norway gets away with low crime despite (or because of) probably the worlds most liberal prison system.
Don't get me wrong. I admire a lot about Japan, but I think you easily fall into the trap of thinking that everything great about Japan is directly the result of something bad.
I would argue more important factor causing law crime in Japan is much the same as in Nordic countries. Low levels of inequality. How people are socialized. Stricter gun laws.
And let us not forget that the average age is high in Japan. Older people commit a lot less crime.