Chronology with superscript denotion of 1 had been validated to the year of 1134 BC for the start of Zhou Dynasty per Sima Qian's Shi Ji. Year 1122 BC was commonly treated as the year when Shang Dynasty ended. Using the first full year as the reign for a new dynasty, Zhou Dynasty counts 1121 BC as the first year of existence. In ancient times, two derivations had been used to determine the exact year Shang Dynasty ended. Ancient Scholar Liu Xin derived 1122 BC, while some others, including Seng Yixing's version in "New History of Tang Dynasty", derived 1111 BC instead. See Zhou Dynasty for a list of Zhou kings.
 
Chronology with superscript denotion of 2 was the result of the Chinese research project which, started in 1995, had been reported to have pushed the exact date to the year 2070 BC as the starting point for Xia Dynasty. Do note that "Chinese Research Project" was heavily influenced by politics and government than a serious academic research.
 
Chronology with superscript denotion of 3 was from China The Beautiful