The result
The IMO's official database records Cho's 2019 entry as seven points on each of the six problems: 42 in total, rank 1, gold medal. Contestants sit two papers on consecutive mornings, three problems in four and a half hours each, and every problem is marked out of seven by coordinators who check each step of the written argument.
Because the maximum is a ceiling rather than a race, all perfect papers share first place. Cho's name therefore appears at the top of the 2019 list alongside five others: Baiting Xie and Zhizhen Yuan of China, Jan Fornal of Poland, and Colin Shanmo Tang and Daniel Zhu of the United States.
Korea at the olympiad
South Korea sends a full team of six to the IMO each year and has been a fixture near the top of the country standings. Cho's perfect paper in 2019 was its only maximum that year, and the country repeated the feat at the next editions in this record: Junhwi Bae scored 42 at Chiba in 2023 and Hyeonjun Lee did so at Shanghai in 2026.
Three perfect Korean papers across four of the olympiads examined here is a strong rate for a six-place team, and it reflects a national selection system that runs through camps and internal olympiads long before anyone boards a plane.
How difficult the 2019 paper was
The number of perfect scores is the quickest measure of a year's difficulty. Bath produced six in 2019. Oslo produced ten in 2022. Bath again in 2024 produced exactly one, when Haojia Shi of China was the only contestant in the world to finish on 42.
That volatility is by design. The problem selection committee aims for a spread in which the easiest problem is accessible to most of the field and the hardest is solved by a handful, so the position of the top of the table moves year to year while the medal ratios stay fixed.
What the record holds
Everything on this page comes from the olympiad's own results database, a primary source maintained by the competition. It gives the host city, the size of the field, the country represented, the per-problem scores, the total, the rank and the medal.
It gives nothing else. There is no age, no date of birth, no school and no photograph in the record for Youngjun Cho, which is why this page carries no birth year and makes no claim about his life outside the examination hall.
What is not known here
No later IMO appearance for Cho appears in the results consulted for this page, and the competition is limited to students in secondary education, so an olympiad career is short by definition.
Where he studied afterwards, what he works on and whether he stayed in mathematics are all outside this file. Pages that answer those questions without naming a source are constructing a life rather than reporting one, which is a particular risk with contestants whose only public record is a row of numbers.
| Person | Country | Milestone | Age / Stat |
|---|---|---|---|
| Youngjun Cho | South Korea | A perfect 42/42 at the International Mathematical Olympiad, 2019 | — |
| Colin Shanmo Tang | United States | A perfect 42/42 at the International Mathematical Olympiad, 2019 | — |
| Galiia Sharafetdinova | Russia | A perfect 42/42 at the International Mathematical Olympiad, 2022 | — |
| Ihor Pylaiev | Ukraine | A perfect 42/42 at the International Mathematical Olympiad, 2022 | — |
| Quy Dang Ngo | Vietnam | A perfect 42/42 at the International Mathematical Olympiad, 2022 | — |
What is documented — and what is not
✓ Documented
- Scored 42/42 at IMO 2019 in Bath for South Korea
- Ranked joint first with a gold medal
- Seven points on each of the six problems
- One of six perfect papers among 621 contestants
? Unverified, disputed or wrong
- No age, date of birth or school in these sources
- No later IMO appearance recorded
- Nothing documented about his studies or career
Questions people ask about Youngjun Cho
What did Youngjun Cho achieve?
A perfect score of 42 out of 42 for South Korea at the 2019 International Mathematical Olympiad in Bath, with a gold medal and joint first place.
How old is Youngjun Cho?
No age or date of birth is published in the sources used here.
How many perfect scores were there in 2019?
Six, out of 621 contestants.
Was he the only Korean with a perfect score that year?
Yes, in the 2019 results consulted for this page.
What is the highest possible IMO score?
42, from six problems worth seven points each.
Is Youngjun Cho on Wikipedia?
No standalone article is recorded for him in this file.
Did he compete at the IMO again?
No later appearance appears in the results used here.
Where is Youngjun Cho now?
The sources used here do not say.
Quick quiz: how well do you know Cho’s story?
Which country did Youngjun Cho represent?
What was his score at IMO 2019?
Which Korean contestant scored 42 in 2023?
Sources
- IMO 2019 individual results — International Mathematical Olympiad (official), 2019
- Youngjun Cho - IMO contestant results — International Mathematical Olympiad (official), 2019
Checked by the Geniuses.club editorial team. Ages are given as of September 2026.
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