This is how Japan wakes up. It's called Radio Taiso — Exercise Radio in English — a simple yet dynamic way to start the day. Japanese radio plays music every morning at 6:30 to accompany basic instructions for calisthenics, and millions perform in the choreography: in parks, workplaces, schools — and at home. Radio Taiso has an almost 100-year history, formally introduced in 1928 and coinciding with the enthronement of Emperor Hirohito. The tradition endures because the exercises are suitable for all ages and capabilities, and easily accessible. We're talking about basic exercise movements: reach to the sky to limber up, twist at the torso, bend at the hips, swing the arms and get the shoulders loose, or jump or run in place. Exercisers can make it as strenuous as they wish, and it's over in just 10 minutes, all done to the rhythm of a soft piano melody. Japan has one of the longest lived populations on earth, and this ritual is credited for promoting physical and social wellbeing.…