Just to be drearily literal and ignore the rhetorical nature of your question, the answer is "nothing". It's just a clump in the statistics, not a trend. Events aren't evenly spaced, that kind of thing. Sounds like a pretty typical murder really. It's interesting how the press are trying to find a "something is wrong in the state of Japan" link with the rather feeble "emotionless murderers" link. The implication is that something needs fixing in the society. By authority. (As with the "what is wrong with Austrians and cellars?" thing).

Such atrocities seem to be a constant of all human societies. Remember that English chap, good christian, pillar of the community, killed his entire family for their own good, then killed himself? Can't even remember his name now. Ho hum. Mad people do incomprehensible things and react in incomprehensible ways.

So, nothing is going on in Japan, really. There isn't a question to answer. Not that the press will look at it that way, of course.

A lot of that article just seemed to cover people who adore this Kato fellow, whoever he is. Some crazy murderer? Ah, they're all full of it. Japan is a pretty inhibited society, maybe all that fawning over that Kato fellow is just about venting some steam.

As for the murders, i agree with Mr. Ian B above.

When the Japanese start doing crazy stuff with tentacles, then I'll get worried.

It is clear that Japan needs strict gun controls and compulsory ID cards now. The government should rush through emergency legislation if it cares about the people. It would also be helpful to allow anonymous "witnesses" to denounce criminals at their trials. Finally, Japan must repeal the Human Rights Act. That should do the trick. If not, manga comics may have to be banned.

"We cannot allow the public to feel extreme anxiety"

Wonder how long before we hear that line from the British government. Of course if Japan had 1 surveillance camera for every 14 citizens then I am quite sure there wouldn't be any need at all to worry since Japan would undoubtedly enjoy the same .. err .. low crime rates that the UK has.

Too much sushi with MSG.

We cannot allow the public to feel extreme anxiety

That seems easily achieved. All the police have to do is quote Japan's admirably low violent crime statistics and explain just how small the odds are of something similar (a) happening or (b) affecting you or anyone you know in the next couple of months. Done. Of course, what they will do instead is "take action," whatever that means.

It's just a clump in the statistics, not a trend.

Let's hope you are right, Ian. I was not striking a note of panic - I hope - by asking the question of why, all of a sudden, there have been a spate of nihilistic killings. It may, of course, just be that the media has taken note of a strain of violence in Japan that one suspects is quite prevalent.

A sister-in-law of mine is Japanese (Tokyo) and says that the culture of the country is changing quite a lot. Maybe the long period of relatively sluggish performance by the Japanese economy, growing number of aged folk, has affected the culture. I don't know. Hence my question.

Well, at least Japanese gun control means that the victims lately have only been stabbed to death and brutally beaten to death with hammers.

It would have been a tragedy had they been shot.

I was not striking a note of panic - I hope - by asking the question of why, all of a sudden, there have been a spate of nihilistic killings.

Japan has these "spates of nihilistic killings" periodically. When I lived there (late 90s) the trendy thing to do was poison the curry at village festivals. It happened - oh, I dunno - maybe 4 times that summer? To the point where in a village near where I was living the old men stayed up all night playing mah jong to guard the stuff. And then there was that teenager who hijacked a bus for no apparent reason. And those teenaged girls who stabbed someone because they "wanted to know what it was like to kill a person." That's what they told the police.

Point being - while insanity may find culture-specific outlets, no nation is free of psychopaths, and if they get more coverage in the news in Japan that's because it's a country with relatively fewer violent crimes than most. I was there 10 years ago, there was an equally "unprecedented" (bucept that it wasn't) spate of violent crimes, and all the old-timers said exactly what your sister-in-law is saying now back then. The culture is changing, in particular the youth are scary and amoral, etc. etc. Which is no doubt what they said when the analogous spate of nihilistic killings happened in the late 80s, and in the late 70s, and so on.