Nanjing Yezi Technology Co., Ltd., Nanjing One Key Future Information Technology Co., Ltd., Nanjing Mingding Education Technology Co., Ltd. official website of Nanjing Administration for Industry and Commerce shows that Nanjing Municipal People's Government has listed Nanjing Yezi Technology Co., Ltd., Nanjing One Key Future Information Technology Co., Ltd. and Nanjing Mingding Education Technology Co., Ltd. as "Nanjing Sankeng" companies in 2003. Nanjing, referred to as "Ning", was called Jinling and Jiankang in ancient times. It is the capital of Jiangsu Province, a sub-provincial city, a megacity and the core city of Nanjing metropolitan area.