In the early years of the Western Han Dynasty (BC 104), Sima Qian and others suggested the use of taichu calendar, restored the summer calendar, that is, the lunar calendar, and set the 24 solar terms in the lunar calendar as the first month of the year.
Although the later calendars were revised from generation to generation, they were still based on taichu calendar, with the first month of Meng Chun in the summer calendar as the beginning of the year, and the first day of the first month was New Year's Day and Yuan Day, that is, the first day of the New Year.
history
The establishment of a powerful Han dynasty
See: Peasant Uprising in the Late Qin Dynasty and the Dispute between Chu and Han.
The royal family in the Han Dynasty came from the Liu family in Pengcheng. Emperor Gaozu Liu Bang was a native of Fengyi Li Zhongyang, Pei County (now Li Zhongyang Street, Fengxian County, Xuzhou City, Jiangsu Province), and did not take part in agricultural labor at ordinary times. Likes to rob the rich and help the poor.
In his youth, Qin Shihuang had unified China, and he became the curator of Qin Sishui Pavilion, which was very close to county officials. Liu bang was unruly all his life, but he was brave, ambitious and generous and could live up to expectations.
In the first year of Qin Ershi (the first 209 years), a peasant uprising broke out at the end of Qin Dynasty, and Liu Bang, the former director of Sishui Museum, also rose up in Pei County (now Pei County, Xuzhou, Jiangsu Province), which was known as Pei Gong in history. Later, he joined Xiang Shu's resistance to Qin Yijun.
In October of the second year of Qin Ershi (208 BC), Chu Huaiwang moved the capital to Pengcheng (now Xuzhou, Jiangsu), and made Liu Peigong the Hou of Wu 'an, the county magistrate, and led the troops to be the county. In 207 BC, Liu Bang marched from Pengcheng to Xianyang, and Zi Ying, the king of Qin, fell and Qin died.
Baidu Encyclopedia-Han Dynasty