Twenty boys from various Cambodian provinces were selected as the first class to attend the College Norodom Sihanouk in 1942. All of them were to be boarders. Saloth Sar was chosen as part of the contingent from Kompong Thom. Unfortunately, the date of his move to Kompong Cham is unknown, so it is impossible to say if he saw the anti-French demonstration in Phnom Penh on July 20, 1942, a demonstration that was quickly absorbed into Cambodian nationalist mythology. It was the most important political event in Cambodia in the early 1940s and the first mass outburst against the French in over twenty years.

In September 1941, just before Sihanouk’s coronation, Admiral Decoux agreed to permit Japanese troops to station themselves in Indochina; in exchange, Japan would allow France to retain administrative control. Encouraged by Japan’s triumphant occupation of most of Southeast Asia in the first four months of 1942, and perhaps supported psychologically and financially by Japan’s secret police, some Cambodians saw the situation as an opportunity to put pressure on the French for political concessions. In July 1942, two Cambodian monks were arrested by the French for preaching anti-French sermons to the local militia. In their haste to bring the monks to justice, the French failed to have them removed from the sangha, and this sacrilege infuriated Buddhists in Phnom Penh. On July 20, Son Ngoc Thanh and Pach Chhoeun organized a demonstration that involved more than five hundred monks and perhaps as many civilians. Led by Chhoeun, the group marched on the office of the French chief administrator (resident supérieur). Thousands—including the French police—watched from the sidewalks of the city’s major boulevard. The Japanese, to Thanh’s chagrin, gave the demonstrators no support. When Chhoeun presented a petition to the French authorities, he was arrested and bundled off to prison. Over the next few days, a handful of his colleagues were rounded up. Thanh went into hiding and soon escaped to Battambang, where he petitioned the Japanese emperor to be allowed to live in Japan. Permission arrived several months later, and Thanh spent the last two years of the war living in Tokyo under an assumed name.