TOKYO -- A string of characters suggestive of the 1989 Tiananmen Square massacre was temporarily embedded in the source code of the University of Tokyo graduate school's website, possibly restricting views from China, the Mainichi Shimbun has learned.

Interviews with university officials and others revealed on Dec. 6 that the string was five kanji letters meaning "six four Tiananmen" -- possibly referring to the June 4, 1989, massacre of civilians by the People's Liberation Army in Beijing.

According to archived data on the internet, the character string was found in the code of the website that the Department of Computational Biology and Medical Sciences of the university's Graduate School of Frontier Sciences had set up in the 2023 academic year. One was in the top page of the English version of the site, and the other in the page showing admissions information. The character string embeds were not there as of the summer of 2023, but were confirmed in November that year.

The string was apparently aimed at inhibiting Chinese students' entry into the school, and the university has launched an in-house investigation, calling the discovery "very regrettable."

Source code is a website's blueprint, and if specific character strings are written into them as keywords, it makes it easier for the sites to be found in some search engines. According to IT industry insiders, if keywords associated with the Tiananmen Square massacre are embedded in source code, it may cause the websites to be rejected by China's censorship system and made inaccessible there.

The university has already changed its system to make it impossible to embed such keywords, and is probing who entered them into the source code.

The university's public relations division told the Mainichi Shimbun, "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 enroll.' 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."

According to publicly available data released by the university, the number of foreign students at the institution has been on the rise year by year. As of May 2024, there were 5,104 foreign students enrolled, roughly 2.4 times the figure in 2004. Of those, 66.5% were Chinese. The proportion increases at the graduate school to 69.4%, including those in professional degree programs.

(Japanese original by Kanami Ikawa, Buntaro Saito and Sahomi Nishimoto, Tokyo City News Department)