A photographed image of a unified university entrance exam question may have been leaked via a video calling app during testing earlier this month, prompting police to investigate the incident as a case of suspected cheating, sources close to the matter said Wednesday.

The incident came to light after a man who identified himself as a University of Tokyo student notified exam authorities that he had received the image of the question on a world history test via the Skype internet telephony app when the examination took place on Jan. 15, the sources said.

Photo taken on Jan. 26, 2022, shows a world history test paper from the unified university entrance exam. (Kyodo)

According to the man, he was asked to "try to solve" the problem by a person he got acquainted with through a tutoring service website, the sources said. He received the image several times and sent back an answer, they said.

The website service operator said the person in question registered with the tutoring service as a second-year high school student in December, asking university students to send contact information and requesting trial lessons.

The man later found out that the question was actually used in the exam and reported the incident to the authorities, the sources said. The National Center for University Entrance Examinations and the education ministry are also examining the incident.

Students take the unified university entrance exam in Tokyo on Jan. 15, 2022. (Kyodo)

"There is a possibility that cheating occurred on the world history test but we cannot give details as we are currently confirming the facts," a center official said.

The man later got a text message from the person asking to also answer literature questions, although he did not actually receive any questions, according to the sources.

According to the center, examinees are told to leave their smartphones and digital devices in their bags during testing.

Following the exam, there were some online posts pointing to the leak of a question.

The unified university entrance exams were held on Jan. 15 and 16, with the testing of geography, history and civics, including the world history exam, conducted from 9:30 a.m. to 11:40 a.m. on the first day.

A total of 417,259 people took the geography, history and civics test, accounting for 78.7 percent of the exam applicants.

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