From AP, via CNN.com:
The Japanese government strongly protested on Saturday a new wave of anti-Japan demonstrations in China, saying Beijing should have prevented the violence.
“Even though information was available beforehand to infer that there would be a demonstration, nothing was done to prevent it … and we strongly protest to the Chinese government,” Japan’s Foreign Ministry said in a statement.
It denounced the “destructive and violent actions” of the protesters and called anew for the Chinese government to prevent a recurrence.