The result in Chiba
The 64th olympiad was held in Chiba in July 2023 with 618 contestants. Each sat two papers on consecutive mornings, three problems in four and a half hours per paper, with every problem marked out of seven.
Bae's official entry carries no partial scores at all: 7, 7, 7, 7, 7, 7. The others who matched it were Haojia Shi and Chunji Wang of China, David-Andrei Anghel of Romania and Derek Liu of the United States. A maximum cannot be beaten, so the five share first place and the gold medals that come with it.
Korea's run of maximums
Across the olympiads examined for this file, South Korea produced a perfect paper in three separate years: Youngjun Cho at Bath in 2019, Bae at Chiba in 2023, and Hyeonjun Lee at Shanghai in 2026. For a country with six places a year, that is a high strike rate at the very top of the scale.
It is also consistent with Korea's standing in the unofficial country table, which is simply the sum of a team's six individual scores. Nations that finish near the top do so by having no weak paper rather than by having one spectacular one, and a 42 inside a strong team is worth the maximum on both counts.
What a seven costs
The marking convention at the olympiad is strict and public. Coordinators read a written proof and award points for complete, checkable reasoning; a correct answer with an unjustified step does not receive full marks, and an elegant idea that runs out of time before the argument closes may receive one or two.
This is why perfect scores are rare even among contestants who solve every problem in their heads. A 42 certifies not only that six problems were solved but that all six solutions were written out completely inside the four and a half hours available for each paper.
How rare five is
Five perfect papers out of 618 is a little under one per cent of the field. The figure swings with the difficulty of the problems: ten contestants reached 42 in Oslo in 2022, six in Bath in 2019, seven in Shanghai in 2026, and exactly one in Bath in 2024.
The medal ratios do not swing. Olympiad regulations cap medals at half the field and award gold, silver and bronze in roughly a one to two to three ratio, which places gold at about one contestant in twelve. Perfect scorers sit in a far smaller category that the rules do not define at all.
What is documented, and what is not
Documented by the competition's own database: the year, the host city, the size of the field, the country represented, the per-problem scores, the total, the rank and the medal.
Not documented anywhere in this file: his age or date of birth, which is why no birth year is given here; his school; his home city; any later olympiad result; and anything about his studies since 2023. No Korean press coverage naming him was collected for this page, so nothing from it is repeated here.
| Person | Country | Milestone | Age / Stat |
|---|---|---|---|
| Junhwi Bae | South Korea | A perfect 42/42 at the International Mathematical Olympiad, 2023 | — |
| Colin Shanmo Tang | United States | A perfect 42/42 at the International Mathematical Olympiad, 2019 | — |
| Youngjun Cho | South Korea | 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 | — |
What is documented — and what is not
✓ Documented
- Scored 42/42 at IMO 2023 in Chiba for South Korea
- Ranked joint first with a gold medal
- Seven points on each of the six problems
- One of five perfect papers among 618 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 Junhwi Bae
What did Junhwi Bae achieve?
A perfect 42 out of 42 for South Korea at the 2023 International Mathematical Olympiad in Chiba, with joint first place and a gold medal.
How old is Junhwi Bae?
No age or date of birth appears in the sources used here.
How many contestants scored 42 in 2023?
Five, out of 618.
Who else wrote a perfect paper that year?
Haojia Shi and Chunji Wang of China, David-Andrei Anghel of Romania and Derek Liu of the United States.
How often does South Korea produce a perfect score?
In the years covered by this file, three times: 2019, 2023 and 2026.
Is Junhwi Bae 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 Junhwi Bae now?
The sources used here do not say.
Quick quiz: how well do you know Bae’s story?
Which country did Junhwi Bae represent?
What was his score at IMO 2023?
How many perfect papers were written that year?
Sources
- IMO 2023 individual results — International Mathematical Olympiad (official), 2023
- Junhwi Bae - IMO contestant results — International Mathematical Olympiad (official), 2023
Checked by the Geniuses.club editorial team. Ages are given as of September 2026.
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