Xiamen Yansen Olympic Mathematics Training Center, Xiamen Ocean Science Union. There are many famous mathematical competition training institutions in Xiamen, including Xiamen Yansen Olympiad Training Center, Xiamen Ocean Discipline Alliance, Xiamen Chiba Olympiad Training Center and Xiamen Yu Hui Olympiad Training Center. These institutions are all specialized in learning mathematics. Xiamen, called "Xiamen" or "Heron" for short, also called Ludao, is a prefecture-level city, a sub-provincial city, a city with separate plans and a class I big city under the jurisdiction of Fujian Province. It is located between 24 23 ′-24 54 ′ north latitude and east longitude117 52 ′-118 26 ′ east coast of Fujian province.