The Chinese sexagenary cycle, also known as the Stems-and-Branches, is a cycle of sixty terms used for reckoning time. It appears as a means of recording days in the first Chinese written texts, the Shang oracle bones of the late second millennium BC. Its use to record years began around the middle of the 3rd century BC. The cycle and its variations have been an important part of the traditional calendrical systems in Chinese-influenced Asian states, particularly those of Japan, Korea, and Vietnam. This traditional method of numbering days and years no longer has any significant role in modern Chinese time keeping or the official calendar. However, the sexagenary cycle is still used in names of many historical events, like Chinese Xinhai Revolution and Japanese Boshin War. It also continues to have a role in contemporary Chinese astrology and fortune telling.