As in other countries of the ancient world, there was no single chronological system in China. Since the 1st millennium BC. e. the dates were designated according to the years of the Van (supreme ruler) reign, therefore the establishment of an absolute chronology sometimes encounters significant difficulties. Thus, modern researchers differently date the Zhou conquest, which led to the fall of the Yin state: this event belongs to some historians to 1122 BC, others to 1066, 1050 or 1027 BC. Only since 341 BC. quite reliable chronology begins in the history of ancient China.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.