Heukseok High School in Heukseok-dong, Dongjak-gu, Seoul, is scheduled to open in March 2026. It will be the first high school to open in 29 years since Chung-Ang University High School transferred to Gangnam-gu in 1997. In the meantime, students in Heukseok-dong had to commute to schools such as Gyeongmun High School and Dongjak High School, 2–3 kilometers away in a straight line. Against this backdrop, local residents have high expectations for the new Heukseok High School.
But ahead of the opening, debate is swirling in Dongjak-gu over the class size per grade at Heukseok High School. Heukseok-dong residents argue that the school's enrollment should be increased, while parents at nearby schools worry about disadvantages if students transfer out to Heukseok High School. The change reflects the growing importance of "number of students" by school under the five-tier grading system for school records and the high school credit system that took effect this year.
The issue began when the Seoul Metropolitan Office of Education set Heukseok High School's class size at 156 students per grade. Under the five-tier grading system, only the top 10% receive a first-tier grade. Even if Heukseok High School fills all seats, calculations suggest the number of first-tier students may fall short of 17.
The impact is greater for inquiry subjects with fewer enrollees. For example, if 30 students take a science subject at Heukseok High School, only up to the top three in the entire school can receive a first-tier grade.
One might think a second-tier grade would be fine. The problem is that with the shift from a nine-tier to a five-tier system, the cumulative share up to the second tier has widened from 11% to 34%. Put simply, unless a student is in the first tier, it may be difficult to get into universities in Seoul.
In particular, starting with the 2028 academic year, major universities including Seoul National University have decided to reflect school records even in regular admissions. That is why both students and parents are more sensitive to the number of students.
The number of students is also connected to the high school credit system, under which students choose and take subjects themselves. The more students there are, the more diverse elective courses a school can offer.
Lim Sung-ho, head of Jongno Academy, said, "In college admissions, the number of high school students is a key factor that determines how many receive a first-tier school record," adding, "The number of students is also important in the high school credit system for schools to offer a variety of elective courses."
Heukseok-dong residents argue that Heukseok High School's enrollment should be raised to the level of nearby high schools. As of 2024, the average number of students per grade at high schools in Seoul is about 217, and the average in Dongjak-gu is around 247. Heukseok High School's per-grade capacity of 156 is relatively small.
A parent living near Heukseok High School, identified as A, said, "Student numbers will keep declining, and I'm even considering moving to another area because of grade tiers." A third-year student at Chung-Ang University Middle School, a girl surnamed Kim, 15, also said, "With only 156 students per grade, it's too few to expect a normal evaluation, so I hesitate to apply."
Lee Hee-won, a Seoul Metropolitan Council member for Dongjak-gu's 4th constituency (People Power Party), said in a phone interview with ChosunBiz, "We asked the education office to add two classes at Heukseok High School to secure at least more than 200 students per grade," adding, "You need more than 200 so that, under the five-tier system, there will be about 20 students in the first tier."
As Heukseok High School expands its capacity, nearby schools could see their student numbers fall. According to the Seoul Metropolitan Office of Education, placement at general high schools in the second admission round is divided into three stages: ▲ Stage 1 (20% of capacity), in which students choose schools from across Seoul; ▲ Stage 2 (40%), in which they choose within the school district based on the student's residence; and ▲ Stage 3 (40%), in which students not placed in stages 1 or 2 are assigned by computer lottery considering commuting convenience.
As a new school, Heukseok High School is unlikely to receive many stage 1 applicants, so a significant number of students are expected to enroll through stages 2 and 3. Currently, the total number of third-year students at Dongyang Middle School and Chung-Ang University Middle School near Heukseok High School is 339. If Heukseok High School's assigned headcount increases by 50–100, nearby high schools could see their student numbers decrease by that amount.
From the perspective of surrounding schools that suddenly face a "zero-sum game," expanding Heukseok High School's capacity is hardly welcome. A second-year student at Gyeongmun High School, a boy surnamed Park, 17, said, "Our first-year juniors already have fewer students than other grades, and if Heukseok increases its capacity, the number of first-tier students will drop further."
A first-year student at Seomun Girls' High School, a girl surnamed Kim, 16, also said, "Because of transfers and other reasons, the total number of students has fallen since we enrolled," adding, "If the headcount drops further, it seems we'll be at a disadvantage in school records."
While discussing the request to increase Heukseok High School's capacity positively, the Seoul Metropolitan Office of Education said it would also consider the positions of nearby schools. An education office official said, "We are working to fill a per-grade capacity close to 200 students at Heukseok High School," adding, "Since applications were accepted through the 5th, we are comprehensively reviewing the number of students and classes at nearby schools."