Shortly before the Newtown killings, a mentally ill peasant went on a rampage with a knife in a primary school in Henan: there were no fatalities. Comparison of the two events seems to be causing quite a bit of discussion across the Sinosphere. School rampages are actually quite a thing in China, but since they involve edged weapons the body count tends to be less. Incidentally, check out the people in China at the above link who think the odd schoolkid massacre is a price worth paying for the right to have guns.
While China's hasn't had a shooting incident at a school, it has had a spree killing triggered by the one child policy. The Tian Mingjian incident:
Being reprimanded after a quarrel with superiors, because his wife was forced to have an abortion and died, Lt. Tian, 31, armed himself with a type 81 assault rifle and began shooting, killing five soldiers and officers, including the Communist Party political commissar of the camp, and injured at least ten more, before he fled the military base in Tongxian County.
While his fellow soldiers were ordered to change into civilian clothing, in order not to disturb the public when searching for the deserter, Tian hijacked a jeep and headed towards Beijing. Arriving in Tiananmen Square at 7:20 am, he jumped out, started shooting people at random and riddled a passing bus with bullets.
17 dead. That was back in 1994. I don't know if the application of the one child law within the PLA has changed since then.
UPDATE: it should be noted that the Chinese gun nuts cited in the link above appear to be very much a minority.
When Chinese viewers looked at the two attacks side by side, more than a few of them concluded, as this one did that, “from the look of it, there’s no difference between a ‘developed’ country and a ‘developing’ country. And there’s no such thing as human rights. People are the most violent creatures on earth, and China, with its ban on guns, is doing pretty well!”