The University of Tokyo has suspended a professor after he allegedly embedded hidden references to China’s 1989 Tiananmen Square crackdown in the source code of university websites.
The university announced on Tuesday that it had taken disciplinary action against the professor in his 60s over the insertion of the kanji phrase meaning “six four Tiananmen” into websites operated by his department and laboratory.
The phrase is widely understood as a reference to the Chinese military’s 4 June crackdown on pro-democracy protesters in Beijing.
Kanji is one of the three core writing systems in Japanese, alongside hiragana and katakana. Originating from Chinese characters, kanji are logographic symbols that represent full words or ideas rather than sounds.
References to Tiananmen Square are heavily censored in China, and it was widely believed that embedding such terms in a webpage’s source code could cause the country’s internet filtering system to block access to the site.
The university said the professor inserted the hidden text into the source code of admissions-related webpages operated by the Department of Computational Biology and Medical Sciences at its Graduate School of Frontier Sciences between 2020 and November 2023.
The incident first came to light in December 2024 after an investigation by Japan’s Mainichi found the hidden character string embedded in the source code of the graduate school’s English-language homepage and admissions pages.
Following an internal investigation, the university suspended the professor for three days on 29 July, the outlet reported.
The Independent has reached out to the university’s Graduate School for Frontier Sciences for comment.
“This was conduct unbecoming of a faculty member of this university and is absolutely unacceptable,” executive vice president Ryuji Yamamoto said in a statement.
At the time of the discovery, the university said that any attempt to inhibit access for students from a specific country would be “very regrettable”.
In a statement at the time, the university said: “Our school holds up the policy of welcoming a diverse body of students and faculty members from both at home and abroad, and seeks to make us ‘a university where everyone in the world wants to enrol’. If the keyword was mixed in with the aim of inhibiting access from a specific country, it is an inappropriate act and is very regrettable.”
It also reportedly modified its web systems to prevent similar hidden code from being inserted in the future.
Online, several commentators expressed concern. “Embedded code can’t be seen by the user. It wasn’t teaching history. It was attempting to prevent Chinese students from attending the university … a place outside China where they could actually learn about the Tiananmen Square incident. It was just racism,” one wrote on Reddit.
Another wrote: “To me, this sounds like the professor didn’t want Chinese international students applying to his programme. Which is punishing students, not the CCP (Chinese Communist Party).”
The incident was alarming because Chinese students made up the largest group of international students in Japan in 2024.
At the time, it was reported that the University of Tokyo had seen a significant rise in international students, with 5,104 enrolled as of May 2024. Chinese students made up the majority – 60.5 per cent of all international students and nearly 70 per cent of graduate students.
According to Japan Student Services Organisation (JASSO), Japan hosted a record 408,069 foreign students as of May this year – surpassing the government’s target of 400,000, which had originally been set for 2033.
The increase also marked a strong recovery after the Covid-19 pandemic, when foreign student numbers fell from about 310,000 in 2019 to around 230,000 in 2022.
According to JASSO, Chinese students were the largest group with 131,097 students, followed by Nepal (100,239), Vietnam (43,366) and students from South and West Asia, including Sri Lanka, also increased.
