It is worth being specific first, because the danger with a birthplace story is that the birthplace becomes the subject and the dead become background. They were not background. Between April 1975 and January 1979 the population of Phnom Penh was marched out of the city at gunpoint and dispersed into rural cooperatives. People worked the rice fields on rations that did not sustain them and died of starvation, untreated malaria and exhaustion. Teachers, monks, doctors, clerks, anyone who spoke French, anyone denounced by a neighbour — they were taken to security centres, interrogated and killed, and their families were killed with them on the principle that a grievance should not be left alive to grow. Cambodians alive today are the children and grandchildren of people who buried siblings in unmarked ground and could not say so out loud for years. That is what the number means.

The family Saloth Sar was born into was not poor, and the fact matters. His father, Loth — later Saloth Phem — farmed nine hectares of rice land and kept several draft cattle, which in a Cambodian village of the 1920s made him a substantial man. Their house was among the largest in Prek Sbauv, and at harvest he hired poorer neighbours to work land he did not need to work himself. His mother, Sok Nem, was known locally as a devout Buddhist and was well regarded for it. Sar was the eighth of nine children, seven boys and two girls; three died young, ordinary arithmetic for a rural family of that era. Those three have no biographies. They are recorded, as village children usually are, only as a subtraction.

The family had a connection that ran straight to the top of the country. Sar's cousin Meak was a consort of King Sisowath Monivong and later taught in the royal ballet, and when Sar was six he was sent from the village to live with her in Phnom Penh. He never really came back. Eighteen months went by as a novice monk at Vat Botum Vaddei; in 1935 he entered École Miche, a Roman Catholic primary school; in 1942 he went to boarding school at Collège Preah Sihanouk in Kampong Cham. He failed the entrance examinations for Lycée Sisowath in 1947 and studied carpentry at the École Technique instead, which in 1949 won him a government scholarship to France, and from 1950 to 1953 he studied radio-electrical engineering in Paris. A palace consort, a French Catholic school, a state scholarship, three years in Europe. Every rung of that ladder was one his movement would later treat as a capital offence in others.

The revolution Pol Pot led was made in the name of the poor peasant — the landless, the labourer, the fisherman. Prek Sbauv had those people. They were the neighbours his father paid by the day, working ground the family owned. When the cooperatives came, the villages of the central plain were not spared on the strength of being rural. The Khmer Rouge broke up families, seized harvests, abolished money and markets, and enforced quotas the land could not meet, and the peasants in whose name all of it was done went hungry alongside everyone else. Whatever the man born here believed he was doing for people like his neighbours, what he actually did to them is a matter of record.

Even his birthday resists settlement. The date usually given is 19 May 1925. French colonial administrative records list 25 May 1928 — a three-year discrepancy of the kind common when rural births were registered late, or by a schoolmaster's guess. His biographer Philip Short argues for March 1925 on other evidence. That a regime obsessed with records and confessions produced a leader whose own birth date cannot be pinned down is an irony worth noting once, then leaving alone.

Very little, is the honest answer. Prek Sbauv is a fishing village indistinguishable from a hundred others on the same water, and nothing in nine hectares of rice land or a pious mother or a childhood spent mostly elsewhere accounts for what followed. The village did not make him; it merely happened to be where he started. What it does offer is scale. Stand on the bank at Prek Sbauv, look at ten houses and a few boats, and hold that against a death toll of nearly two million, and the disproportion is the whole point. Ordinary places produce ordinary lives. Once in a very long while they produce something the rest of the country spends generations recovering from, and the place itself goes on fishing, because what else is it supposed to do?