TOKYO (THE YOMIURI SHIMBUN/ASIA NEWS NETWORK) - Thirty people who would have passed entrance exams to Osaka University in February 2017 were instead considered to have failed due to a mistake in a physics question and how it was marked, the university said.

Osaka University was twice told by people outside the university that the question contained an error, but failed to take appropriate corrective steps. It was only after the error was pointed out for a third time that the university examined the matter.

That took about six months from the time the university was first clearly notified by a third party, until it realised the entrance exams contained an error.

The university in Suita, Osaka Prefecture, said all 30 people will be recognised as having passed the test, and those who wish to switch to the university can start attending classes as first-year or second-year students from April.

Some of these 30 people are reportedly attending other universities or university preparatory schools, so Osaka University will pay compensation and reparations for the extra tuition and other expenses incurred by these students, the university announced on Saturday (Jan 6).

The physics question was included in the general entrance exams for six schools, including engineering and science. Nine students who would have passed the exams for the schools of engineering, engineering science, and science, which were their top preference, have since started studying at their second choice.

Osaka University will allow these students to change to their first preference.

The university immediately sent letters notifying the students they had passed, after completing the review of the marking and its admission decisions.

According to the Education, Culture, Science, Sports and Technology Ministry, the case is of an unusual scale among entrance exam mistakes committed in recent years by national universities.

"The university should have systematically detected and dealt with the error much sooner," said education ministry official Taizo Yamada, who is in charge of university entrance exams.

Osaka University has been urged to examine the cause of the error thoroughly and take steps to prevent it from happening again.

According to the university, 19 of the 30 students sought to enter the engineering school; four for the science school; two each for the medicine, pharmaceutical sciences, and engineering science schools; and one for the dentistry school.

In total, 3,850 students took the physics exam.

The error affected two questions about sound waves. One question involved a mathematical formula and had three right answers, but only one was graded as correct. The other question required a numerical value that depended on the answer from the first question.

Doubts about this exam question were first raised in June 2017 by attendees at a meeting of an association for physics education. The association, which comprises high school teachers and others, was examining Osaka University's entrance exam.

At the meeting, it was pointed out there could be several correct answers. A School of Science professor from the university, who was responsible for writing the exam questions, was at the meeting and said there was only one correct answer.

In August, a third party sent an e-mail to the science school and suggested the question might contain an error. But the professor and other university representatives sent the same explanation to the sender via its Admissions Office.

On Dec 4, when another person explained in detail why the question was flawed, four different professors joined in to look at the case. They then discovered the error.

At a press conference, Osaka University executive vice-president Tadashi Kobayashi said the delay in discovering the mistake was due to "the person responsible for writing the question having a preconceived notion that they were right".

To prevent similar mistakes, Mr Kobayashi said the university will check questions during the compilation process and recheck them after an exam. It will also set up an exam question verification committee headed by an executive vice-president.

Osaka University president Shojiro Nishio said: "We'll give the utmost consideration to the students who took the exams, and wholeheartedly deal with each one while considering their individual circumstances."