The Japanese word ikigai (生き甲斐) combines iki, meaning 'life,' with gai, meaning 'worth' or 'value.' Together they point to the reason you get out of bed each morning — your personal sense that life is worth living. Unlike sweeping concepts such as 'life purpose,' ikigai can be something modest and immediate: tending a garden, perfecting a recipe, or simply sharing tea with a neighbor.

The authors discovered this concept during research visits to Okinawa, a Japanese island chain famous for producing more centenarians per capita than almost anywhere on Earth. Residents there rarely retire in the Western sense; they keep doing what gives their days meaning well into their nineties and beyond. That continuity, the authors argue, is itself part of why they live so long.

Importantly, ikigai is not a destination you reach once and possess forever. It is an ongoing orientation — a daily practice of noticing and nurturing the things that make you feel alive. Losing touch with it, studies suggest, is genuinely dangerous: research cited in the book links a lack of ikigai to higher rates of cardiovascular disease and early death.