Their universal healthcare system helps of course. As does a healthy national diet that features green tea, seafood and seaweed among other nutrient-packed fare.

In his 2009 TED talk, National Geographic’s Dan Buettner made reference to the health-giving benefits of ikigai, as he talked about the secret of people who live to be 100 year old or older.

“They [the Japanese] have vocabulary for sense of purpose, ikigai,” he said. “You know the two most dangerous years in your life are the year you're born, because of infant mortality, and the year you retire. These people know their sense of purpose, and they activate in their life, that's worth about seven years of extra life expectancy.”

Want to know more? Put a pre-order on these two books - Ikigai: The Japanese Secret to a Long and Happy Life by Héctor García and Francesc Miralles and The Little Book of Ikigai by neuroscientist Ken Mogi, both coming out this autumn.

Images: Getty

This Japanese formula for happiness is intriguingly simple