The sequence of development of culture or the relationship between events that represent culture can be established only when events can be placed in proper time.Chronology, the study of events in time frame, is hence the central theme of archaeologist, like the geologist who deals with the story of earth history.The deposit thus occurring forms layers depending on the nature of the material brought in by the people inhabiting the area.According to this method, the upper deposits are younger and the lower deposits are older.In May 2003, the National Museum of Japanese History (NMJH) announced, that the beginning of Yayoi period dates back to 500 years earlier than it had previously been thought; charred remains stuck to pottery samples had been analysed by AMS 14C dating (HARUNARI et al. A few archaeologists accepted the new dating right away, while many scholars expressed critical opinions.Especially the archaeologists in the Kyūshū region, who had been playing a leading role in the dating of Yayoi period, strongly rejected it.The emergence of man through the process of biological and cultural evolution is a story of long span of time.For the archaeologist and the prehistorian who deals with that long history of man, time is the most important consideration.
But, even when the scientific methods of absolute dating are available, this method of dating has not lost its importance, as many a time we have to depend solely on relative dating.
Even when the absolute dates are available, we have to supplement the information with relative dating.
The various methods of relative dating are; This method depends on the common observation that the height of the habitational area increases as the people continue to live at the same place.
On the other hand, absolute dating includes all methods that provide figures about the real estimated age of archaeological objects or occupations.
These methods usually analyze physicochemical transformation phenomena whose rate are known or can be estimated relatively well.