Seoul (AFP) - Survivors from one of South Korea's worst maritime disasters were among hundreds of thousands of high school students across the country who sat the high-pressure annual college entrance exam on Thursday.
Preparation for the crucial exam starts from primary school, and the relentless pressure to score well has been blamed for everything from early burnout to teenage depression and suicide.
In an ultra-competitive society, the test plays a large part in defining the students' adult lives, holding the key to a place at a top university and the elevated social status, as well as job and even marriage prospects that go with it.
More than 630,000 students turned out for the exam on Thursday and, as happens every year, the entire country went into hush-mode for the duration.
The extraordinary measures taken to ensure nothing affects the student's concentration include a 35-minute suspension of all aircraft takeoffs and landings at South Korean airports to coincide with the main language listening test.
The Transport Ministry said 69 scheduled flights had to be readjusted because of the suspension with four domestic flights cancelled for the day.
All arriving flights that are in the air must maintain an altitude exceeding three kilometres until given permission to land.
The exam is a stressful rite of passage for any student - but for none more so this year then several dozen students from Danwon High School in Ansan, south of Seoul.
In April last year, 325 of the school's students were on an organised trip to the southern resort island of Jeju when the passenger ferry they were in sank.
Only 75 of them survived.
The Sewol ferry disaster stunned the entire nation and a shrine to the dead erected near the Danwon school became an unofficial memorial to the tragedy.
Most of the surviving students were in the same grade and took part in Thursday's exam - seen off at the test centres by their anxious parents.
"After what happened she became quite withdrawn and shunned people as well as her studies," Jang Dong-Won, 46, said of his daughter.
"But she somehow pulled herself out of it, and ended up hitting the books hard, staying late at school to study with her classmates," Jang said.
The survivors were offered a dispensation to apply to colleges without taking the exam, but most declined, despite the difficulties they had getting back into the gruelling study routine the test demands.
Public offices and major businesses, as well as the stock markets, opened an hour later than usual Thursday to help keep the roads relatively clear and ensure the students arrived on time for the exam which began at 8:40am (2340 GMT).