(by S. Miyauchi, Professional Engineer, Doctor of Engineering, JSME Fellow)
China civilization which has advanced so early has many world's first technologies such as the Great Canal (2,000km from Beijing to Guangzhou), a lock, a large-scale dam like Dujiang Yan (BC251 of Qin dynasty), an arc bridge like Anji Bridge (605), a junk (watertight bulkhead, junk rig), cast iron, porcelain, paper, gunpowder, a compass, a stirrup, a crossbow, heavy cavalry and civil service examination (科挙). Japan introduced these since Yayoi era (BC3C to 3C). For example, Daisenryou Mausoleum which is world’s three biggest mausoleum with Giza Pyramid and Mausoleum of First Emperor of Qin was built in early 5C. It is 486m in total length and 36m in height. In addition, till 3C rice farming which need advanced irrigation technology spreaded out to Aomori (North end of Honshu Island, Northern latitude 40 ° 42 '). Agriculture tools (hoes and plows) mass-produced by cast iron might be used for these.
