In an Indian home, where the elderly intone, "Jug, jug jiyo", you know that blessings for a long life have been preferred over happiness. But, on the Japanese island of Okinawa, longevity never required godly intervention. It enjoys the highest average number of centenarians in the world—24.55 people over the age of 100 for every one lakh inhabitants. The women live even longer. Back in 2015, the island caught the attention of Spaniards Héctor García and Francesc Miralles. The result of their journey there is the new bestselling global rage, Ikigai: The Japanese Secret to a Long and Happy Life (Penguin Random House).

Barcelona-based Miralles first heard about the "immortal" and "incredibly joyful" Okinawans from his friend García, who had married a woman from the island. "We knew there was something more interesting at work," he says in a telephonic interview. The two decided to undertake a year-long psychological investigation on the island. "We observed how they [the residents] lived, related to each other, and what their general philosophy of happiness was. During interviews, they mentioned the word ikigai, once too often," he remembers. The book, originally written in Spanish, attempts at unravelling this mysterious idea that has even found a fan in American talk show host and philanthropist Oprah Winfrey.