In the foothills of Mount Kagami, bordering the long beach of Matsubara, this magnificent forest of black pines dates from the 17C. Some 500 metres wide and 5km long with a surface area of 240 hectares, it counters erosion by blocking the wind and strong tides in the bay. Formerly called Matsubara Nisato, "the forest of a million trees" by the feudal lord of Karatsu, it acquired its current name, Niji-no-Matsubara "pine forest of the rainbow" during the Meiji Period.