UPDATE (April 28, 2013): Press outlets originally reported that authorities intended to encourage Internet Service Providers (ISPs) to block Tor; this has since been corrected. Police allegedly are encouraging website administrators to blocks users of the program.
According to an April 18 news report , Japan's National Police Agency  (NPA) may soon urge website administrators to ‘voluntarily’ block users from accessing their sites via Tor,  the anonymous online communication program. The NPA report carrying this announcement has not been formally released; whether NPA will actually put this move into practice remains unknown.
A report published in late January  [ja] quotes the chair of the NPA cyber security committee [temporal translation] saying:
As for Tor, for example we would suggest to limit access from Tor. This is something outside of investigation and should proceed as a policy with consensus of the citizens. We would like to discuss from this standpoint.
At Global Voices Online, we have written about Tor which offers a protective measure allowing users to remain anonymous in online environments where freedom of expression is limited and surveillance is prevalent.
The proposed NPA policy would be a voluntary effort to keep criminals from using anonymous networks as a way to issue threats against others. Still, the hacker collective Anonymous had something to say to NPA. ChanologyAgent who claims to be the Anonymous of Japan uploaded a message  on Youtube on April 19.
What is regrettable is that Tor is not the dark and dangerous shadow network that you and the mass media would like to paint it as. Tor is merely a tool, and like all tools, it can be used both responsibly and irresponsibly.
The truth is, the Tor network helps people in repressive countries, such as Tibet, bypass censorship and communicate with the outside world. It helps whistleblowers safely expose unethical behavior by powerful people. Tor can and is used every day for noble ends.
At our last count, there were 52 Tor nodes operating in Japan, several of those exit nodes. Each and every one of those nodes contributes to the strength and stability of the network, and the exit nodes in particular help users in less fortunate countries than ours.
By discouraging Tor use in Japan, you weaken the strength of the entire network. You reduce the options for people in repressive regimes. And you rob your own people of a legitimate and perfectly legal tool they can use to protect their privacy in a world that regards it as less and less important with each passing day. We urge you to withdraw this report and renounce your recommendation for ISPs to block the Tor network in Japan.
On social networks and citizen media, users responded to the news, mostly with indignation. On bookmarklet service hatena, users commented in cynicism  [ja] that the country's Internet is “turning Chinese”:
umeten : That's it, there will be no more the “Internet”
Another user, activecute,  jokingly writes that communication methods may be very limited in the future.
activecute : why don't we tame pigeons to be carrier-pigeons…or we may be sent to jail in 30 years later
arajin  :「一方で、中東の民主化運動では政府の弾圧から逃れるため民衆が活用。」国内で起きているのは愉快犯。どちらが重大かは自明。
arajin : it says [in the article] “on the other hand, Tor was used by citizens in oppressive regimes during Arab Spring.” Compare this to what's happening in Japan, which is more like vicious users playing with threatening comments [without real action]. It's obvious the former matters.
@needle : Now the police start saying that they want to restrict Tor via ISP. I knew they would say that sooner or later, but this could violate the right to communications privacy. What do they mean by ” ask the public for understanding”?
On technology news blog techdirt.com , user JarHead posted a comment wondering whether this move has any effect in decreasing online crimes.
JarHead : Say that there's an “effective” ways to block Tor. What's to stop people to just abandon ship and use yet another anonymizer? Tor isn't the only one in the game, there are others. Then they'll be calling to block those as well, and people just pick up yet another one. This will go on and on until everything is blocked including legal channels.
Police were criticized last year for making wrongful arrests  of citizens who they identified using IP addresses. On user submitted news site and forum slashdot.jp  [ja], many commented, doubting the ability of the police to tackle cyber crimes.
However, hatena bookmark user festerfester writes that measures are needed and that the anonymous online bulletin board is becoming the hotbed for crimes .
festerfester : 警察の情報通信関係の捜査のずさんさには心底憤りを感じるけど、だからといって２ちゃんねるなどの悪質な書き込みを放置していいという話は全く別問題のはず。元管理人とかあまりにも無責任すぎると思う。
festerfester : I do feel furious about the cops for being so terrible at investigating cyber crimes. With that said, it's a different story that vicious posts on 2channel can be remain untouched. I think the former manager of the 2channel is way irresponsible.
Global Voices Advocacy will continue to cover this threat as it takes shape in Japan. If you have information or ideas for our Japan Internet policy coverage, tweet to us @Advox.