While walking in a park in Tokyo last weekend, an old Japanese man, standing with a stick and carrying a Canon camera with a long lens, motioned me to step backwards. When I decided to turn away, he waved at me to come forward. Pointing to something in the woods, he whispered in my ear that there was a special bird in the trees. He showed me the photos of birds and flowers he had shot in the park. He said he visits the place, which, with its plants carrying name plates, is designed to teach children about nature, twice a week with his camera and a lunch-box. He said it takes him two hours by subway and bus to get to the park from his home.

Most of his photos were out of focus, but his passion touched my heart.

Whenever I go to parks in the Japanese capital, I often encounter energetic, gray-haired amateur photographers and painters.

Japanese believe that a sense of purpose or a reason to jump out of bed each morning, known as ikigai in Japan, helps them live a long, healthy life. Iki means "life", and gai "to be worthwhile".

The Japanese have an average life expectancy of 83.7 years old, outliving the rest of the global villagers. Their women, in particular, are incredibly resilient with an average life span of 86.8 years, ranking second after Hong Kong, according to the World Health Organization.

Two writers, Hector Garcia and Francesc Miralles, explored the secrets behind the art of Japanese staying young while growing old, including doing interviews in Okinawa, which has the largest population of centenarians in the world.

In their coauthored book Ikigai: The Japanese Secret to A Long and Happy Life, Garcia and Miralles say nurturing friendships, eating light meals, getting enough rest and doing regular, moderate exercise are all part of the equation of good health, but at the heart of the joie de vivre that inspires the centenarians to keep celebrating birthdays and cherishing each new day is ikigai.

One thing I notice in Japan is how active people remain after they retire. In fact, many Japanese people never really retire. They keep doing what they love for as long as their health allows.

A friend of mine, Michio Hamaji, worked in Middle East before retiring. Now the 70 something man is freelancing as a consultant for two companies. I wonder where his energy comes from.

Japanese men, who are the breadwinners of their families, are remote persons who disappear in the morning and reappear late at night. Jeff Kingston, director of Asian Studies of Temple University's Tokyo Campus, said they can find the transition away from being worker drones very difficult because they haven't nurtured networks outside of their jobs and are often strangers in their neighborhoods and, in some cases, their families.

The issue for Japanese is too much work. Government data show that about 4.3 million people, or 8 percent of the Japanese labor force, worked more than 60 hours a week last year. With a standard workweek of 40 hours, those workers are putting in more than 20 hours of overtime a week.

Despite the culture of working long hours, which drives some people to commit suicide, most Japanese survive and live a long life. Studies have found that purposefulness is one of the strongest predictors of longevity and passion brings meaning to life.

Ken Mogi, a neuroscientist and writer, argues in his 2017 book, The Little Book of Ikigai: The Essential Japanese Way to Finding Your Purpose in Life, that it doesn't matter whether "you are a cleaner of the famous Shinkansen bullet train, the mother of a newborn child or a Michelin-starred sushi chef'－if you can find pleasure and satisfaction in what you do and you're good at it, congratulations you have found your ikigai".

Ikigai hides in everyone. Have you found yours?

The author is China Daily Tokyo bureau chief.?