I wonder what would happen if the US made a requirement that to get a student visa to study here, applicants from China have to take and pass a history course about Tiananmen Square and the subsequent efforts to cover it up?

There are around 360k Chinese students in the US. If China didn't do anything to counter it, that would be a lot of educated young people eventually returning to China to take influential jobs who are aware of Tiananmen.

Would China go so far as to stop allowing their students to study in the US to stop that? Or would they just to to convince the students that the US is lying?

Chinese students are cash cows for universities. Wouldn't be surprised if they found a way to argue against complying with any such mandate that endangered this rather important profit center. As far as the Chinese government goes, they could require pre and post briefings for all students studying in the United States. It wouldn't avoid the students being exposed to what happen in Tiananmen Square but under the right conditions, with the right carrots and sticks, they could be made to either be skeptical or disinterested in the truth. As Upton Sinclair said 'It is difficult to get a man to understand something, when his salary depends on his not understanding it.'

At Auburn University in the late 90s there was a seemingly random murder of a Chinese grad student and his wife. The local police were mystified because it didn't match a typical homicide and there appeared to be no motive, not even robbery. Eventually it turned out that the student was the son of a important regional politician back in China. His enemies had the son and daughter-in-law murdered in the United States to send him a message. Similar demonstrations of the long reach of the Chinese government could be made to students studying in the United States if they as a group started creating difficulties for the official narrative.

The students that make it to the USA mostly know things like that already. Their ideological positions, one way or the other, are not influenced much by ignorance.

I've met several Chinese students whose personal Tiananmen epiphanies were in the States, not on the mainland.

Epiphanies and knowledge are different things.

Confucius Institutes are arms of the Chinese state that operates on US university campuses that monitor and report on their citizens' activities while they're studying in the US, as well as organizing propaganda events in the US. US universities must stop collaborating with these institutes and expel them from campus, even if only to protect their students as much as possible.

It's a lot easier for those students to learn about it once outside of China. No firewall, less groupthink, less fear of being watched.

How many are unaware, and how many pretend to be unaware because they know they're expected to be unaware?

Here's a weeks long thread where I engage in a conversation with a (allegedly) Chinese student about such topics.

For those that have bought into the propaganda, the impression is generally that the government put down a dangerous riot that was killing innocents.

Start of the Twitter uh "thread" (not sure how to refer to these) https://twitter.com/Chinahnpy/status/1129327748743409664?s=2...

Here's the start of some tiananmen discussion: https://twitter.com/komali_2/status/1133764941675094016?s=20

Yes, there’s a lot of people who know nothing of Tiananmen at all, but often those that do would characterize it as a riot by agitators who forced the governments hand.

I think the central government now advocates apathy rather than forgettance. Young people get apathy, so it’s an easier sell.