Chinese philosopher and novelist Lin Yutang shrewdly noted in My Country and My People (1935) that “patriotism is simply nostalgia for the foods of one’s childhood”. Hong Kong’s ongoing fondness for the humble sweet potato, in all its delicious variations, further validates this simple, yet potent, truth. Many botanical introductions across maritime Asia came as a direct result of the 16th century Portuguese voyages of global exploration, trade and conquest. Sweetcorn and maize, tomatoes, guavas and – most notably – the chilli; none of these now-universal food plants existed anywhere in Asia until European settlers introduced them. Unlike the common potato – another botanical migrant from Central America – sweet potatoes can tolerate poor soils and humid, subtropical conditions, and thus became more widely cultivated. While the Portuguese were responsible for the wider dissemination of these species, the first introductions usually came via the Spanish, who brought seeds and tubers across from Mexico to the Philippines on their annual silver bullion transports from Acapulco to Manila. From the Philippines, these new crops spread into southern China via Macau, and – less widely recognised – Amoy. Chinese trading settlements existed in Luzon long before the first Spanish arrival, in 1521, and regular voyages between Fujian and the Philippines introduced numerous plant species into China over the next century. Introduction of maize and sweet potatoes did much to stave off hunger in large parts of China with limited arable land and – as the 18th century ended – rural unrest due to overpopulation. Throughout history, armed uprisings, peasant revolts and revolutionary movements have found their genesis in grave human misery, as chronic hunger steadily became acute starvation. When people feel they finally have nothing left to lose except their lives – which famine will soon deprive them of anyway – violent social unrest inevitably erupts. The French revolution offers but one well-documented example. Solid academic arguments suggest that the Manchu regime in China, which finally collapsed in 1911, survived for about a century longer than it might otherwise have done due to the widespread introduction into desperately poor rural areas of “New World” food crops. “No rice to eat, eat sweet potatoes!” is a common Cantonese saying, wryly quoted by an older generation who lived through the Japanese occupation. From urban Hong Kong’s earliest years, there has never been an adequate supply of locally produced rice to meet demand, which made the colony a net importer of rice, mainly from Southeast Asia. As shipping disruptions became more widespread during the latter stages of World War II, largely due to the American submarine blockade, rice became scarce, and correspondingly expensive; sweet potatoes were a widely available substitute. Wartime deprivation connotations aside, sweet potatoes were once widely grown as pig food; for that reason, they can be psychologically unappealing to people from impoverished rural backgrounds, who – as material prosperity advances – come to feel that they should eat something “better” as part of their daily diet. The great divide: Hong Kong’s harbour has long set the boundary for a tale of two cities Charcoal-roasted until they are soft and fragrant, sweet potatoes remain a popular Hong Kong street food, especially in the cooler months, and can usually be purchased alongside roasted chestnuts and baked quail eggs. Chunks of sweet potato poached in watery broth with ginger and rock sugar are a perennially popular Cantonese homestyle dessert. Sweet potato tops are an easily grown leaf vegetable, and can be prepared in numerous tasty ways. During the Pacific war, military prisoners of war and civilian internees in Japanese camps in various parts of East Asia cultivated the sweet potato on available scraps of land, mainly for the additional vitamins supplement that the fast-growing, easily harvested leaves provided. In Taiwan, this vegetable is more commonly known as “ground melon leaf”, and it has become increasingly popular both there and in Hong Kong for its health-giving properties.