U.S. based watchdog organization Freedom House compiled a report on Freedom on the Net 2013 and included the report on Japan for the first time.

Japan was evaluated as “Free”,  where the constitution protects all forms of speech and prohibits censorship, and Internet and digital media freedom are generally well established. For key developments during May 2012 to April 2013, Freedom House reported that: 

• Political speech was constrained online for 12 days before the December 2012 election under a law banning parties from campaigning online.
• In April 2013, the legislature overturned that law, but kept restrictions on campaign emails.
• 2012 amendments to the Copyright Law criminalized intentionally downloading pirated content, though lawyers called for civil penalties.
• Anti-Korean and anti-Chinese hate speech proliferated online amid real-world territorial disputes.  
• A constitutional revision promoted by the newly-elected LDP party threatens to erode freedoms and rights that “violate public order” .

You can read the full report here.