From the BBC:

Four Japanese rules to live past 100

Okinawa, long known as the island of the immortals, is home to the highest concentration of centenarians in Japan. The village of Kitanakagusuku ranks first in Japanese women's longevity. What is it about this island that makes its inhabitants live a longer and happier life?

Video by: Shiho Fukada and Keith Bedford

The rules have been variously described as exercise, diet, and socializing (5:08, 5:25), or diet, physical activity, self-help, and a mutual help system (3:00), not to mention Ikigai (spiritual health or a personal mission).