The problem that cost him 2024
Kano's scoresheet in Bath reads 7, 7, 2, 7, 7, 7. Five of the six problems were fully solved and fully written; the third was marked two out of seven, which in olympiad terms means real progress that did not close into a proof.
That single deduction was the difference between fourth place and the top of the table. 2024 was the hardest paper in this record: of 609 contestants, only Haojia Shi of China reached the maximum, and 37 was enough for fourth in the world.
The perfect paper
The 2025 olympiad drew 630 contestants to the Sunshine Coast in Australia. Kano's line in the results is six sevens: 42 out of 42, rank 1, gold. Four others matched him, Ivan Chasovskikh, Warren Bei of Canada, and Leyan Deng and Hengye Zhang of China.
Coming back a year after a near miss and removing the gap is the pattern selectors look for. Olympiad problems are not repeated and cannot be revised for; what improves is a contestant's ability to close an argument under time, which is exactly what the two scoresheets, read side by side, record.
Japan at the olympiad
Japan has been a consistent presence near the top of the country standings and hosted the competition itself in 2023, at Chiba. In the years examined for this file, Yuya Oki wrote a perfect Japanese paper at Oslo in 2022 and Kano wrote the next one in 2025.
National teams are capped at six contestants, so a country's standing is a sum of six scores and a perfect paper is a sixth of the team's ceiling. Japanese teams have tended to score evenly rather than rely on a single star, which makes a maximum a visible event in the country's coverage of the competition.
How the marking works
Six problems are set across two mornings, three per paper, four and a half hours each. Every problem is marked out of seven by coordinators who read the written proof and award credit for complete reasoning only, which is why partial scores like Kano's two in 2024 are common.
Medals are then awarded to no more than half the field, in roughly a one to two to three ratio of gold to silver to bronze, so gold falls to about one contestant in twelve. A 42 is outside that framework altogether: it is simply the ceiling, and everyone who reaches it shares first place.
What is documented, and what is not
Documented by the olympiad's official database: both years, both host cities, the field sizes, Japan as his country, the per-problem scores, the totals, the ranks and the medals.
Not documented: his age or date of birth, which is why no birth year appears here; his school or city; the Japanese characters for his name, which the research file flags as unconfirmed; and anything he has done since the 2025 competition.
| Person | Country | Milestone | Age / Stat |
|---|---|---|---|
| Satoshi Kano | Japan | A perfect 42/42 at IMO 2025 after fourth place in the world in 2024 | — |
| 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 2025, joint first with a gold medal, for Japan
- Scored 37/42 at IMO 2024 for fourth place overall
- 2024 per-problem scores were 7, 7, 2, 7, 7, 7
- One of five perfect papers among 630 contestants in 2025
? Unverified, disputed or wrong
- No age, date of birth or school in these sources
- The Japanese spelling of his name is unconfirmed
- Nothing documented about his studies or career
Questions people ask about Satoshi Kano
What did Satoshi Kano achieve?
A perfect 42 out of 42 for Japan at the 2025 International Mathematical Olympiad, after finishing fourth in the world in 2024 with 37 points.
How old is Satoshi Kano?
No age or date of birth appears in the sources used here.
What was his 2024 scoresheet?
7, 7, 2, 7, 7, 7. Almost all of the shortfall came from the third problem.
How many perfect papers were written in 2025?
Five, out of 630 contestants.
Where was the 2025 olympiad held?
On Australia's Sunshine Coast.
Is Satoshi Kano on Wikipedia?
No standalone article is recorded for him in this file.
How is his name written in Japanese?
The Japanese spelling is not confirmed in the sources used here.
Where is Satoshi Kano now?
The sources used here do not say.
Quick quiz: how well do you know Kano’s story?
What did Satoshi Kano score at IMO 2025?
Which problem cost him marks in 2024?
Which country does he compete for?
Sources
- IMO 2025 individual results — International Mathematical Olympiad (official), 2025
- IMO 2024 individual results — International Mathematical Olympiad (official), 2024
Checked by the Geniuses.club editorial team. Ages are given as of September 2026.
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