Image A student who was wounded Wednesday in an attack in Guangdong Province, where 15 students were stabbed. Credit... Associated Press

“The three killers wanted to get revenge on society,” one person, Zhang Han, wrote in an Internet chat posting. “They considered themselves as ‘underprivileged,’ and they chose an even more vulnerable group, children, to get revenge. Doubtless their own psychological problems played an indispensable role. But social inequality is obviously the catalyst.”

There likely is no single explanation for the assaults in Fujian, Shandong, Jiangsu and, on Wednesday, in Guangdong Province, where a 33-year-old former teacher stabbed 15 fourth-and fifth-graders. (In China, where access to guns is tightly controlled, knives are one weapon of choice in violent crimes.) Many Chinese might correctly note that their situation is hardly unique; the United States and other nations have also endured violent attacks on students.

Yet some aspects of the assaults — the alacrity with which they were copied by new assailants, to cite one example — raised questions among some Chinese about whether something else was at work here. Curiously, the four attacks in March and April mirror a series of assaults in August and September 2004, in which students in four other schools and a day care center were attacked by knife-wielding men who stabbed dozens of children.

One theme echoed in some Internet postings was the feeling by many Chinese citizens that they had little power in the face of authority, and few ways to right wrongs. One posting compared the attacks to a notorious rampage in July 2008 by a man who said he felt he had been wronged by the police. In a single attack in Shanghai, the man, Yang Jia, stabbed six police officers to death — and he became a national hero by the time he was executed that November.

Image Zheng Minsheng was sentenced to death in the March 23 killings of eight children in Fujian Province. The attack was the first of four recent ones. Credit... China Daily, via Reuters

One person who posted in a chat room pointed out that after the attack in March, a student wrote a letter to the assailant, saying, “If you’ve got hatred, please go to kill the corrupted official.”