Overview: On this week's "journeys in japan," we visit Karatsu city in Saga prefecture. The area, which looks out to the sea, is blessed with a warm climate. People here have long enjoyed marine sports. A legendary French diver had strong ties with the sea of Karatsu. Jacques Mayol was the first man in the world to free dive to 100 meters. And it was a childhood encounter with a dolphin off the coast of Karatsu that inspired him to dive. Our reporter Ian Thomas Ash investigates the diver's deep connection to Karatsu. (Excerpt)