Li Chang Yen

In the novel The Big Four, Li Chang Yen (AKA Number One) is the Chinese leader and mastermind of the group the Big Four. Poirot call him as "my great opponent".

Hastings and Poirot first hear about Li Chang Yen from Mayerling, a British secret service agent whom they found dying in Poirot's bedroom. He told them that Li is the brains, the motive force of the Big Four. More background cames from John Ingles, a retired civil servant and expert on China. Ingles had actually met Li once. He says he is the controlling brain in the East. Going further he talks about a belief held by some that there is a person behind the scenes bent on causing the disintegration of civilisation motivated by a lust for power and supremacy. Prominent political firgures in the limelight are merely puppets of him. Ingles is convinced Li is that person. He is said to have access to unlimited amounts of money for bribery and propaganda and also control over some scientific invention of great power. Despite all this, Li is hardly known in public--he seldom leaves his palace in Peking.

People who spoke against Li in public mysteriously died. One Chinese chemist who wanted to tell Mr Ingles about experiments Li had ordered on humans. The chemist sought refuge with Ingles but died when Ingles' house mysteriously burnt down. Throughout the novel (or short story series), Li was believed to have been behind the deaths of several key individuals who threatened to expose him or the Big Four. One was an old seaman Jonathan Whalley who said "the Big Four" was after him (what he knew or did to be killed for is not explained). Another is Mr Paynter, a traveller and writer who was writing a book "The Hidden Hand in China". He was poisoned and the manuscript stolen.

Despite Li's involvement in the Big Four, he is never seen throughout the book. And despite the mystery surrounding him and his preference to act behind the scenes, he is the only one of the Big Four whose identity is known at the beginning of Poirot's investigations. The others would not be known until almost the end of the book. At the end Poirot reads in a newspaper that Li had committed suicide. Presumably he had taken his life when he heard about how the Big Four and his colleagues had been eliminated. Poirot remarked that it was fated that he and Li were not to meet.