Emmanuele Contini/NurPhoto via Getty Images
It's no secret that people on Chinese social media dislike Japan.
The list of perceived grievances keeps growing, from the Rape of Nanking in World War II to fears of seafood in the Pacific Ocean being tainted by radioactive water from the Fukushima disaster.
That rhetoric was stoked again on June 24 when a knife-wielding man in Suzhou attacked a Japanese woman and her son at a school bus stop, injuring the pair.
But it was the third victim who seized the country's attention. School bus attendant Hu Youping, a 55-year-old Chinese woman, rushed to protect the two foreigners, suffering stab wounds herself.
She died later while receiving medical care, police said. They identified the suspect as an unemployed 52-year-old man with the surname Zhou, saying he'd only recently arrived in the city.
A whirlwind of emotion and debate ensued on social media. Hu was lauded as a hero — with some clamoring for the bus stop to be named after her — while anti-Japan hate speech swelled in posts and comments implying the attack was warranted.
As the two narratives intertwined, Chinese social media companies intervened in lockstep. It was clear the extremism had gone too far.
Tech giant Tencent published a statement on Saturday condemning the hate speech and said it would crack down on posts related to the Suzhou stabbing that "provoke extreme nationalism." Tencent runs WeChat, a super app that performs functions similar to WhatsApp and Facebook.
NetEase, a major gaming company, published a similar announcement, saying it observed posts calling for "resisting Japan and exterminating traitors" and accusing Hu of being a Japanese spy.
Douyin and Weibo, China's versions of TikTok and Twitter, publicly slammed accounts that they said "promote extreme xenophobia" and "cheered for criminal behavior in the name of patriotism."
The platforms said they took down thousands of posts and removed several dozen accounts.
It's a rare rebuke of nationalism on these platforms, a hotbed for inflammatory posts like the 2022 calls to shoot down then-House Speaker Nancy Pelosi's plane when she visited Taiwan.
Though China's social media is heavily moderated, anti-Japanese rhetoric has been one of several popular nationalistic sentiments allowed to flourish in recent years.
As of Wednesday, the main hashtag for posts about the Japanese victims of the June knife attack was censored. However, discussion of Hu's death and her posthumous recognition for bravery are still allowed.
In recognition of Hu's actions, Japan's embassy in China flew its national flag at half-mast.
It's unclear if China's central government was directly involved in the crackdown. But social media firms in the country react sensitively to what the state deems acceptable, often simultaneously issuing announcements about undesirable posts.
China's Cyberspace Administration tasks social media platforms with self-regulating content and, on June 14, published a set of rules detailing how internet providers should censor violent content.
The anti-Japanese rhetoric also comes at an inconvenient time for Chinese officials hoping to bring in more business from Tokyo as the local economy struggles.
Suzhou, in eastern China's Jiangsu province, is one of the country's largest hubs for Japanese investment, with thousands of Japanese firms in the city.
On Tuesday, Chinese state media reported that Vice Premier He Lifeng had met with a trade delegation from Japan, saying his country welcomed Japanese companies and hoped they would expand.
Hu's death hung over the meeting, with officials on both sides pausing for a moment to honor her passing, The South China Morning Post reported.
