It is just after sunset and hundreds of people have gathered around the docking bays of Minamiboso on the southern edge of Chiba Prefecture. As men bang away on taiko drums, dozens of women emerge from a hilltop shrine. Dressed head-to-toe in white outfits and wearing goggles on their heads, they carry lit bamboo torches and walk, two-by-two, toward the docks. These are ama (female divers), and as they wade into the water to form a circle, onlookers watch in near silence — save for the sound of digital and analog shutters.