Police are investigating allegations of widespread cheating among students taking a key South Korean exam.
The exam is seen as so important, mothers pray for their children
Scores of students are suspected of using their mobile phones to receive texted answers, while others have confessed to candidate substitution.
Education is a national obsession in South Korea, and many people believe the results of the College Scholastic Ability Test determines future success.
Police said many texts on the day of the test, 17 November, were suspicious.
They said some of these only consisted of numbers from 1-5, The Korea Herald reported.
The exam in question is mostly multiple-choice, and is taken by 600,000 students across the country.
Some students have reportedly admitted cheating, and one report said that the total number of people involved could be 300.
"It is mainly due to pressure to do well in a test that will decide their lives forever," said Jung Bong-mun, an Education Ministry official.
The cheating taps into both a belief in good education - as emphasised by the country's Confucian tradition - and technological prowess.
Three quarters of South Korea's population have at least one mobile phone.