🇬🇧 Alex Chui

Alex Chui was born in Hong Kong and began his Olympiad career there. In 2020 he made his debut on the Hong Kong team at the International Mathematical Olympiad and took a silver medal — a respectable result for a first appearance, and one that would have been a career highlight for most competitors. The following year, still representing Hong Kong, he converted that silver into gold.

In 2022 he moved to England and to Tonbridge School in Kent, and switched allegiance to the United Kingdom team. What followed was one of the most sustained runs of excellence in the history of school-age competition mathematics: three further golds and another silver across the next four Olympiads, each earned against the strongest sixth-form mathematicians on the planet.

The scale of that achievement is easy to under-read. The IMO is a two-day examination of six problems, three per day, four and a half hours per paper, each problem marked out of seven. The problems are not difficult in the way school examinations are difficult; they are designed so that a substantial fraction of the world's best young mathematicians will fail to solve any of them completely. Consistency at this level is close to impossible, because a single unlucky problem can cost a medal. Chui was never once outside the medals in seven attempts.

The finale came at IMO 2026, hosted in Shanghai — a return to China for a competitor born there. Chui scored 42 out of 42: every problem solved completely, no partial credit anywhere. Only six other contestants out of 666 managed the same. His result helped the United Kingdom to joint eighth place overall, with three golds among the British team.

Dr Geoff Smith, Chair of Trustees at the United Kingdom Mathematics Trust and one of the most experienced Olympiad organisers in the world, described the result as astonishing. 'The dazzling performance of the British pupils at IMO 2026 will lift the spirits of everyone who celebrates excellence in education and problem solving,' he said. 'They all did well, but Alex Chui's achievement in becoming the most decorated IMO contestant of all time is astonishing.'

With that final gold, Chui overtook Canada's Zhuo Qun Song — also Chinese-born — as the most successful participant in the competition's history. Song had won five golds; nobody had ever won seven medals of any colour. Because IMO eligibility ends when a competitor leaves secondary school, the record is unusually resistant to being broken: a challenger would need to qualify for a national team at eleven or twelve and then medal every single year without exception.

Owen Elton, Tonbridge's head of mathematics, framed the ending as the only one that fitted. 'It is fitting that Alex has capped his unprecedented IMO career with a perfect score,' he said. 'The only competitor ever to have won seven medals, he is likely to sit atop the Hall of Fame for decades. We, in Tonbridge School's maths department, are absolutely thrilled for him, wish him luck as he goes up to Cambridge, and will keep a keen eye out for his future mathematical contributions.'

What makes Chui interesting is not raw calculating speed — the quality Olympiad mathematics rewards is closer to invention. Competitors are handed problems nobody has seen before and given four and a half hours to construct an argument that a hostile marker cannot break. Seven years of medalling means seven years of walking into that room and reliably producing original proofs under time pressure, as a schoolboy, against the best in the world.

He goes up to Cambridge with a record that will be quoted in Olympiad circles for a generation. The history of the IMO is, in retrospect, a reasonable predictor of research mathematics: Terence Tao won IMO gold at thirteen, Grigori Perelman took a perfect score in 1982, and Maryam Mirzakhani won two golds before her Fields Medal. Chui's mathematical life has barely begun; the medals are the prologue.

It is worth being precise about what the International Mathematical Olympiad actually is, because the name misleads. It is not a quiz. Each country sends a team of six secondary-school students, who sit two four-and-a-half-hour papers of three problems each, drawn from algebra, combinatorics, geometry and number theory. The problems are chosen by an international jury specifically so that a complete solution requires an idea the contestant has never been taught. Marks are awarded out of seven per problem, and partial credit is famously grudging.

In 2026 the competition drew 666 contestants. Roughly half go home without a medal at all. Gold is awarded to about the top one-twelfth. Against that distribution, seven appearances producing seven medals — five of them gold — is not a run of form; it is a decade-long refusal to have an off day at the one moment each year when an off day costs everything.

The Olympiad has also become an unusually reliable early indicator. Its alumni include a striking share of the last four decades of Fields Medallists, and the competition's Hall of Fame doubles as a watch-list for research mathematics. Chui arrives at Cambridge already at the top of it.