Step into a Hong Kong supermarket today and you’ll find few limits on what you can buy. Want mangoes in winter or cruciferous vegetables in summer? No problem, thanks to globalisation and advances in refrigeration and greenhouse technology. With everything available year-round, the traditional concept of seasonality has lost much of its original meaning, often reduced to a cliché in the marketing of new restaurants.

Far from a passing fad, this astronomical and natural calendar – which outlines China’s “micro-seasons” – was, until around a century ago, the world’s longest-running culinary philosophy, defining Chinese agriculture and eating habits.