 The system mainly refers to Japanese system.The measurement refers to the traditional size of a Japanese flooring mat called a Tatami mat (made of woven dried grass) which were positioned to completely cover the floor of traditional Japanese homes, therefore it became a convenient measurement tool as the mats size was standardized hundreds of years ago.In Taiwan the measurement units are pronounced in Taiwanese Hokkien and Hakka before the World War II and adopted by the Mandarin speaking immigrants from China in 1949.